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Emergency Medicine Atlas > Part 1. Regional Anatomy > Chapter 2. Ophthalmologic Conditions >

Neonatal Conjunctivitis (Ophthalmia Neonatorum)

Associated Clinical Features

Neonatal conjunctivitis is acquired either during birth with passage through the mother's cervix and vagina or from cross infection in the neonatal period. Microbiologic etiologies include Chlamydia trachomatis, viruses (herpes simplex), and bacteria (Neisseria gonorrhoeae, Staphylococcus aureus, Streptococcus pneumoniae, groups A and B streptococci, Haemophilus species, Pseudomonas aeruginosa, and Escherichia coli). Of these, S. aureus is the most frequent and N. gonorrhoeae the most important. Clinical findings in neonatal conjunctivitis include drainage, conjunctival hyperemia, chemosis, and lid edema.

Neisseria gonorrhoeae presents as a hyperacute bilateral conjunctivitis. Distinctive findings include a copious purulent drainage (Fig. 2.1) and preauricular adenopathy. The incubation period, like that for sexually transmitted N. gonorrhoeae, is 3 to 5 days, although the onset may vary. In chlamydial conjunctivitis, the incubation period is 5 to 12 days. Clinical features of chlamydial conjunctivitis include unilateral conjunctivitis and concomitant otitis media or pneumonia. Herpes simplex conjunctivitis generally begins 2 to 14 days after birth; fluorescein staining demonstrates epithelial dendrites.

Figure 2.1

Neonatal Conjunctivitis (Ophthalmia Neonatorum) Copious purulent drainage in a newborn with neonatal gonococcal conjunctivitis. (Reprinted with permission of the American Academy of Ophthalmology, Eye Trauma and Emergencies: A Slide-Script Program. San Francisco, 1985.)

Differential Diagnosis

Dacryocystitis, corneal abrasions, foreign body, and an obstructed nasolacrimal duct present with redness and tearing. Neonatal glaucoma may also be mistaken for conjunctivitis; findings include eye pain, photophobia, corneal haze, corneal enlargement, and excessive tearing.

Emergency Department Treatment and Disposition

The neonate with conjunctivitis must be evaluated carefully for systemic involvement. With any form of neonatal conjunctivitis, smears and cultures are mandatory and therapy should begin immediately thereafter. Scrapings of the palpebral conjunctiva for cultures and Gram stain are more revealing than examination of the discharge itself. Topical therapy for a neonate whose Gram stain demonstrates gram-negative diplococci includes aqueous penicillin (10,000 to 20,000 U/mL one drop every hour for 6 to 12 h, followed by one drop every 2 to 3 h until resolution). Saline irrigation of the conjunctival cul-de-sac prior to antibiotic instillation may be helpful. Systemic therapy involves intravenous penicillin G (50,000 U/kg/day in two or three doses for 7 days). Pediatric consultation is advised.

Chlamydial conjunctivitis is treated with oral erythromycin estolate. Neonatal bacterial conjunctivitis that is neither gonococcal nor chlamydial may be treated with antibiotic ointment (erythromycin, tetracycline, or gentamicin four to six times a day for 2 weeks) and should be reevaluated in 24 h. Herpes simplex conjunctivitis is treated with intravenous acyclovir and topical trifluorothymidine.

Evaluation of the newborn's parents should be undertaken in neonatal conjunctivitis due to N. gonorrhoeae, Chlamydia, or herpes simplex virus.

Clinical Pearls

1. Neonatal conjunctivitis may be caused by chemical, chlamydial, viral, and bacterial agents.

2. The "rule of fives" is fairly accurate in predicting the most likely bacterial etiology.

0 to 5 days:	N. gonorrhoeae
5 days to 5 weeks:	Chlamydia
5 weeks to 5 years:	Streptococcus or Haemophilus influenzae

3. The cornea should be examined for involvement. Corneal ulcers, perforation, permanent scarring, and blindness can quickly result from gonococcal eye infection in the neonate. It is one of the few urgent conjunctival infections.

4. A detailed maternal history may help with the diagnosis of neonatal conjunctivitis secondary to N. gonorrhoeae, Chlamydia, or herpes.

Bacterial Conjunctivitis

Associated Clinical Features

Bacterial conjunctivitis is characterized by the acute onset of conjunctival injection and mucopurulent drainage. Staphylococcus aureus is the most common causative bacterium. Streptococcus pneumoniae and Haemophilus influenzae occur more frequently in children. The purulent drainage (Fig. 2.2) commonly leads the eyelids to be stuck together on awakening. Lid edema and erythema, chemosis, and superficial punctate keratitis may also be present.

Figure 2.2

Bacterial Conjunctivitis Mucopurulent discharge, conjunctival injection, and lid swelling in a 10-year-old with Haemophilus influenzae conjunctivitis. (Courtesy of Frank Birinyi, MD.)

The most severe form of acute purulent conjunctivitis is associated with Neisseria gonorrhoeae. Infection can be seen in children of any age, including the newborn. Clinical symptoms are hyperacute in onset and include a discharge that is prominent, thick, copious, and purulent. Other findings include marked eyelid swelling, along with tenderness, marked conjunctival hyperemia, pain, chemosis, and preauricular adenopathy. The condition may progress to involve the cornea, because Neisseria species are capable of invading an intact corneal epithelium. Corneal findings include a diffuse epithelial haze, epithelial defects, marginal infiltrates, and peripheral ulcerative keratitis, which can rapidly progress to perforation.

Neonatal conjunctivitis is discussed separately.

Differential Diagnosis

Other etiologies of conjunctivitis (viral, allergic) as well as iritis, glaucoma, scleritis, and foreign body also present as a red eye.

Emergency Department Treatment and Disposition

Treatment involves local hygiene with warm, moist compresses and frequent hand washing, along with broad-spectrum antibiotic drops (10% sulfacetamide, gentamicin, ofloxacin, ciprofloxacin, or trimethoprim/polymyxin B). One drop every 3 h for 7 to 10 days usually results in rapid resolution. If there is no response, cultures and ophthalmologic consultation should be sought.

The treatment of gonococcal conjunctivitis is both systemic (ceftriaxone 25 to 50 mg/kg/day, not to exceed 4 g/day, given in one dose IM for 7 days) and topical (penicillin G 100,000 U/mL one drop every 2 h or bacitracin ophthalmic ointment 500 U/g every 2 h, tapering over 48 h to five times a day). Patients with corneal involvement should receive additional intravenous ceftriaxone (1 g every 12 h). Sexual partners should be advised and evaluated.

Clinical Pearls

1. Worsening symptoms during topical treatment with any antibiotic, particularly Neosporin or a sulfonamide (Sodium Sulamyd), may represent a contact allergic reaction.

2. Conjunctivitis due to N. gonorrhoeae must be considered in the sexually active adult with a prominent, thick, copious, and purulent eye discharge.

3. Neisseria species are capable of invading an intact corneal epithelium.

4. In early or mild cases of bacterial conjunctivitis, symptoms may be limited to mild conjunctival injection without frankly purulent drainage that is evident to the physician. Thus, empiric antibiotic therapy is warranted in most cases of conjunctivitis.

Viral Conjunctivitis

Associated Clinical Features

Viral conjunctivitis is an infection caused most commonly by adenoviruses. Clinical features range in severity but usually are mild and typically include burning or irritation, conjunctival injection, lid edema, chemosis, and a thin, watery discharge. The infection usually begins in one eye, but both eyes generally become involved because of autoinoculation (Fig. 2.3). The palpebral conjunctiva may demonstrate hyperemia and follicles, which are hyperplastic lymphoid tissue appearing as gray or white lobular elevations. The palpebral conjunctiva also may demonstrate papillae. Papillae are seen in many acute inflammatory diseases, secondary to a hyperplastic conunctival epithelium being thrown into numerous folds and projections. Clinically, papillae give the palpebral conjunctiva a velvety appearance. Preauricular adenopathy may be present. Severe cases may demonstrate focal or diffuse subconjunctival hemorrhages as well as pseudomembranes. A punctate keratitis may appear several days after the onset of symptoms, followed several weeks later by subepithelial infiltrates. The visual acuity and pupillary reactivity are normal.

Figure 2.3

Viral Conjunctivitis Note the classic asymmetric conjunctival injection. Symptoms first developed in the left eye, with symptoms spreading to the other eye a few days later. A thin watery discharge is also seen. (Courtesy of Kevin J. Knoop, MD, MS.)

Pharyngoconjunctival fever, usually caused by adenovirus type 3, is highly infectious and should be considered if there is fever, upper respiratory tract infection (cold, flu, or sore throat), and preauricular adenopathy. It is seen predominantly in the young and institutionalized, with epidemics occurring in families, schools, and military camps.

Epidemic keratoconjunctivitis is discussed separately.

Differential Diagnosis

Similar symptoms are seen in allergic and bacterial conjunctivitis and other causes of a red eye, such as scleritis, glaucoma, and iritis. Less common diagnoses include preseptal cellulitis and dacryoadenitis.

Emergency Department Treatment and Disposition

Many cases are self-limited and mild. Cool compresses are helpful. Meticulous hygiene (hand washing by the family and instrument cleaning by medical personnel) is necessary to prevent spread. Because the signs and symptoms of viral conjunctivitis do not always suffice to distinguish it from bacterial conjunctivitis, antibacterial eye drops are usually prescribed. Antivirals are ineffective against adenovirus. Topical steroids should be avoided. Symptoms may persist for several weeks; follow-up is indicated if symptoms have not begun to resolve within 4 to 7 days.

Clinical Pearls

1. Adenoviruses are the most common cause of acute conjunctivitis. However, a complete eye examination is necessary to rule out other more serious causes of a red eye before the diagnosis of viral conjunctivitis is made.

2. Adenovirus most commonly demonstrates a follicular conjunctivitis. Papillae may also be seen on the palpebral conjunctiva.

3. Pharyngoconjunctival fever should be considered in the setting of fever, upper respiratory tract infection, and conjunctivitis.

Epidemic Keratoconjunctivitis

Associated Clinical Features

Epidemic keratoconjunctivitis (EKC) is a severe and highly contagious adenovirus infection involving the conjunctiva and cornea. Viral transmission usually occurs through direct or indirect contact with the ocular secretions of infected individuals. The incubation period after exposure is about 8 days. Initial symptoms include watery or mucopurulent discharge, foreign-body sensation, and mild photophobia. Clinical findings include edema of the eyelids, chemosis, marked diffuse conjunctival hyperemia, subconjunctival hemorrhage, and a follicular and papillary conjunctival reaction (Fig. 2.4). Pseudomembranes overlying the palpebral conjunctiva and tender preauricular nodes may be present. A painful keratitis, typically involving the central cornea, develops in about 80% of patients, usually around the eighth day. The keratitis initially appears as fine punctate epithelial lesions that stain with fluorescein (Figs. 2.5, 2.6). These lesions coalesce and continue to stain with fluorescein. By the end of the second week, the keratitis is replaced by white macular, subepithelial infiltrates located in the central cornea. These lesions no longer stain with fluorescein. They may cause a significant decrease in vision and photophobia for months and even years, but they eventually resolve spontaneously. These subepithelial infiltrates are believed to result from a host immune response rather than from active viral replication.

Figure 2.4

Epidemic Keratoconjunctivitis (EKC) Diffuse injection of the bulbar conjunctiva is seen in addition to a papillary reaction of the palpebral conjunctiva—a classic finding in EKC. (Courtesy of Katrina C. Santos.)

Figure 2.5

Epithelial Keratitis This usually develops after 5 to 7 days and is seen as a fine punctate abrasion pattern over the cornea. (Courtesy of Katrina C. Santos.)

Figure 2.6

Fluorescein Stain This demonstrates epithelial keratitis from the prior photo. (Courtesy of Katrina C. Santos.)

Symptoms usually begin unilaterally in young adults during the fall and winter months. Bilateral involvement may develop 4 to 5 days later, with less severe symptoms in the second eye, probably due to partial immune protection of the host. There are few to no systemic complaints. Thus, in patients with systemic complaints and associated fever, upper respiratory tract infection, pharyngitis, otitis media, and diarrhea, the diagnosis is more likely to be pharyngoconjunctival fever, which is also caused by an adenovirus. Pharyngoconjunctival fever is seen predominately in the young, with epidemics occurring in families and schools.

Differential Diagnosis

Other viruses and causes of red eye (bacterial conjunctivitis, iritis, scleritis, glaucoma, herpetic infection) need be considered.

Emergency Department Treatment and Disposition

Although EKC may be severe, the condition is self-limited and therapy is mainly palliative. Cool compresses, topical vasoconstrictors (Vasocon), and dark sunglasses provide symptomatic relief. Antibiotics and antivirals are ineffective. However, topical broad-spectrum antibiotic drops are usually prescribed, since it is difficult to distinguish viral from bacterial conjunctivitis. In the presence of pseudomembrane formation, topical broad-spectrum antibiotic ointments may be prescribed to lubricate and protect the cornea. The use of topical corticosteroids is controversial. They may have a role in patients with marked symptoms such as severe conjunctival pseudomembrane formation, severe foreign-body sensation, or reduced visual acuity secondary to epithelial or subepithelial keratitis. Although topical steroids do provide effective symptomatic relief, they have no beneficial therapeutic effect on the ultimate clinical outcome. Patients with EKC should limit their exposure to others for 2 weeks after the onset of the disease and use separate linens.

Clinical Pearls

1. A nonspecific adenoviral conjunctivitis will resolve in 10 to 14 days; a virulent adenovirus causing EKC will peak in 5 to 7 days and may last 3 to 4 weeks.

2. Frequent hand washing and the use of separate linens is advised for patients and family members to reduce exposure.

3. Pharyngoconjunctival fever should be considered if there is an associated fever and upper respiratory tract infection.

4. EKC may be nosocomially transmitted by tonometry (the footplate of the Schiøtz tonometer, the prism of the applanation tonometer), contaminated solutions (topical anesthetics), and the physician's fingers. Regular hand washing by the physician and patient and careful cleaning (using alcohol or Dakin's solution followed by rinsing) and sterilization of instruments are therefore important. Adenovirus can be recovered for extended periods of time from these surfaces.

Allergic Conjunctivitis

Associated Clinical Features

Allergic conjunctivitis is a recurrent condition whereby airborne allergens precipitate hypersensitivity reactions in the conjunctiva. Potential allergens include pollens (ragweed, grasses, trees, weeds), animal dander, mold, and dust. Itching is the hallmark symptom. Allergic conjunctivitis is usually transient and self-limited and is seasonal if it is due to pollens. However, it can present as a single acute episode if the allergen is animal dander, mold, or dust. There may be a personal or family history of atopy, eczema, asthma, and allergic rhinitis (hay fever). Ocular allergic conditions are more common in males and tend to commence in the first or second decade of life.

In addition to the hallmark symptom of itching, associated clinical features include conjunctival injection and edema, burning, discharge (clear, white, or mucopurulent), and chemosis (swelling of the bulbar conjunctiva). Chemosis may be marked and may actually balloon beyond the lids. Small to medium-sized papillae (hyperplastic conjunctival epithelium thrown into numerous folds and projections) appear as small elevations on the palpebral conjunctiva (Fig. 2.7) and give the tissue a velvety appearance. Pallor of the palpebral conjunctiva may be present due to edema. The eyelids may be red and swollen.

Figure 2.7

Allergic Conjunctivitis Conjunctival injection, chemosis, and a follicular response in the inferior palpebral conjunctiva in this patient with allergic conjunctivitis secondary to cat fur. (Courtesy of Timothy D. McGuirk, DO.)

Vernal conjunctivitis is an infrequent but serious form of allergic conjunctivitis that mainly affects young males (4 to 16 years of age) during the warm months or in tropical climates. Again, a family or personal history of atopy is common. In addition to a hereditary predisposition, exogenous factors play a role in the severity and likelihood of this disease. The Middle East and North Africa, with arid areas and wind and dust storms, have the highest incidence of vernal conjunctivitis. Symptoms of vernal conjunctivitis are similar to those of allergic conjunctivitis but greater in degree. Itching is intense, and a vigorous knuckle rubbing is a typical observation. Giant, raised, pleomorphic papillae ("cobblestones") are seen over the upper tarsal plate (but rarely over the lower tarsal plate) and are pathognomonic for the disease (Fig. 2.8). The drainage of vernal conjunctivitis is also pathognomonic and is characteristically tenacious, copious, thick, and ropy. Corneal findings include a sterile ulcer (well delineated with an oval or shield shape and no surrounding haze or iritis), Horner-Trantas dots (raised white limbal infiltrates), and superficial punctate keratopathy.

Figure 2.8

Vernal Conjunctivitis The tarsal conjunctiva demonstrates giant papillae and a cobblestone appearance pathognomonic for vernal conjunctivitis. (Courtesy of William Beck.)

Differential Diagnosis

Other etiologies of a red eye (scleritis, iritis, glaucoma, bacterial conjunctivitis) should be considered.

Emergency Department Treatment and Disposition

The severity of the allergic condition is directly proportional to the level and duration of the allergen exposure. Therefore, initial therapy is primarily aimed at identification and elimination of the allergen. Avoiding animal dander, using air conditioners with appropriate filters, limiting time outdoors (to avoid pollen-bearing wind), or the use of goggles or glasses outdoors will improve the condition.

Topical tear substitutes (four to eight times a day) are effective in diluting or washing away the allergen. For mild allergic conjunctivitis, H₁ antihistamine-vasoconstrictor combinations successfully alleviate itching, redness, and swelling. Vasocon-A (one to two drops every 3 to 4 h) is effective and contains an antihistamine (0.5% antazoline) and a vasoconstrictor (0.05% naphazoline). Olopatadine (0.1%, one to two drops bid) is an antihistamine with mast cell–stabilizing properties that also relieves the itching and redness effectively. Mild topical steroids are an option after consultation with an ophthalmologist for those cases where all other modalities have been explored. A short course of prednisolone (0.12%) two to three times a day is unlikely to result in any ocular complications.

Additional therapeutic agents for vernal conjunctivitis include cromolyn sodium solution 4% (one to two drops every 4 to 6 h), aspirin (650 mg four times a day orally), and cold compresses. Topical cyclosporine (0.5%) may be useful in resistant cases of vernal conjunctivitis.

Clinical Pearls

1. Itching is the hallmark symptom of ocular allergy.

2. Removal of the offending allergen, if possible, is the first step in the treatment of allergic conjunctivitis. The patient is usually the best source for identifying the allergen to which he or she is sensitive.

3. Vasocon-A and olopatadine are effective in treating allergic conjunctivitis.

4. Topical corticosteroids may be used in severe cases but should be prescribed only with ED ophthalmology consultation. Complications include glaucoma, cataract formation, secondary infection, and corneal perforation.

5. Vernal conjunctivitis affects mainly children and adolescents; it peaks in the warmer months.

6. Evert the upper lid to appreciate the giant conjunctival papillae in vernal conjunctivitis. Their cobblestone appearance is pathognomonic.

Hordeolum/Chalazion

Associated Clinical Features

A hordeolum is an acute purulent infection and a localized abscess involving the meibomian glands, the glands of Zeis, or the glands of Moll (Fig. 2.9). Staphylococcus aureus is the most frequent isolate. An external hordeolum (stye) involves an eyelash follicle and the adjacent glands of Zeis or Moll (Fig. 2.10). An internal hordeolum involves the meibomian glands within the tarsal plate. A chalazion is a chronic localized lipogranulomatous inflammation that results from the obstruction of the meibomian glands. A chalazion may evolve from a hordeolum but usually arises spontaneously secondary to blockage or obstruction of the gland. The impacted secretions of the gland are then extruded into the surrounding tissues, producing a foreign-body reaction to sebum and a lipogranulomatous inflammation. Chalazia are commonly seen in the ED (Fig. 2.11).

Figure 2.9

Eyelid Anatomy Anatomic structures related to eyelid pathology.

Figure 2.10

Hordeolum Focal swelling and erythema at the lid margin are seen in this hordeolum. (Courtesy of Frank Birinyi, MD.)

Figure 2.11

Chalazion This chalazion shows nodular focal swelling and erythema. (Courtesy of Frank Birinyi, MD.)

Common signs and symptoms include pain, focal swelling, edema, erythema, and tenderness. In the case of an external hordeolum (stye), an abscess localizes around the root of an eyelash, followed by necrosis of the skin and spontaneous evacuation of the abscess at the lid margin. An internal hordeolum, produced by obstruction of the meibomian duct with associated bacterial infection, demonstrates a localized inflammation of the tarsal plate. In the case of a chalazion, focal inflammation may cause pointing of the lesion either anteriorly (toward the skin of the eyelid) or posteriorly (toward the tarsal conjunctiva) (Figs. 2.12, 2.13). A chalazion may become sufficiently large as to press on the globe and cause astigmatism (corneal distortion that prevents focus). A chronic chalazion may appear as focal lid swelling without associated signs of inflammation.

Figure 2.12

Chalazion This chalazion is in an early stage. Lid swelling is evident, with pointing of the chalazion to the inner tarsal conjunctiva. (Courtesy of Kevin J. Knoop, MD, MS.)

Figure 2.13

Chalazion Pointing of the chalazion to the tarsal conjunctiva is more evident with slight lid eversion. (Courtesy of Kevin J. Knoop, MD, MS.)

There may be associated marginal blepharitis (Fig. 2.14) (a chronic low-grade inflammation of the lid margins with crusts around the lashes) or acne rosacea (a dermatologic condition with facial hyperemia, acneiform lesions, hypertrophy of sebaceous glands, and rhinophyma).

Figure 2.14

Blepharitis Inflamed, erythematous eyelid margins consistent with blepharitis. (Courtesy of Kevin J. Knoop, MD, MS.)

Differential Diagnosis

Sebaceous cell or squamous cell carcinoma should be suspected in older patients with recurrent or persistent lesions. Preseptal cellulitis should be considered if the entire lid is erythematous and edematous. Pyogenic granuloma has a similar appearance but includes hypertrophic tissue as well as a vascular core, and it bleeds easily. Dacryocystitis should be considered if the lesion involves the medial aspect of the lower lid.

Emergency Department Treatment and Disposition

The clinical course of a hordeolum may be self-limited, with spontaneous drainage of the abscess and resolution within 5 to 7 days. Treatment for both hordeola and chalazia includes warm compresses 2 to 4 times a day for 15 min. Warm compresses help to localize the infection and inflammation and may expedite spontaneous drainage. Systemic antibiotics are unnecessary unless there is a significant cellulitis. Topical antibiotic ointment cannot directly affect the inflammation inside the gland but is an adjunctive therapy to decrease the local bacterial flora. The application of a broad-spectrum antibiotic ointment, such as bacitracin or erythromycin, every 3 h to the conjunctival sac is effective. If the mass persists beyond 3 to 4 weeks or if the lesion is sufficiently large to distort vision, referral to the ophthalmologist should be made for incision and curettage or intralesional corticosteroid injection. Gentle scrubbing of the eyelids and lashes may be indicated if marginal blepharitis is noted.

Clinical Pearls

1. Chalazia are often found in patients with marginal blepharitis, probably because the orifices of the meibomian gland are blocked by the blepharitis infection.

2. Excisional biopsy is indicated for recurrent chalazia to exclude malignancy.

Dacryocystitis

Associated Clinical Features

Dacryocystitis, an inflammation of the lacrimal sac, is usually secondary to obstruction of the nasolacrimal duct. Hallmark findings are tearing (epiphora) and discharge. Acute dacryocystitis is associated with pain, swelling over the lacrimal sac (Fig. 2.15), erythema, and tenderness. Mucopurulent discharge may be expressed from the punctum when pressure is applied over the lacrimal sac. In adults, acute infection is due to Staphylococcus aureus or occasionally beta-hemolytic streptococci.

Figure 2.15

Dacryocystitis Swelling and erythema over the medial lid and lacrimal sac developed in this 10-year-old patient with streptococcal pharyngitis. (Courtesy of Kevin J. Knoop, MD, MS.)

In the newborn, 4 to 7% have a closed nasolacrimal passage. In these cases the duct usually opens spontaneously within the first month. Dacryocystitis is uncommon but may nevertheless develop, and aggressive treatment is required to avoid orbital cellulitis. Haemophilus influenzae is the most common organism isolated. Organisms usually seen in chronic dacryocystitis include Streptococcus pneumoniae or, rarely, Candida albicans.

Dacryocystitis is uncommon in the intermediate age groups unless it follows chronic sinusitis, facial trauma, or (rarely) neoplasm.

Differential Diagnosis

Chalazion, facial and orbital cellulitis, canaliculitis, canalicular stenosis, sinus tumors, ethmoid sinusitis, and mucoceles have similar features.

Emergency Department Treatment and Disposition

Acute dacryocystitis usually responds to oral antibiotics (amoxicillin-clavulanate), warm compresses, and gentle massage. Topical antibiotics may be used in chronic cases. Nonurgent ophthalmology or otolaryngology referral is required for definitive treatment—relief of the obstruction by dacryocystorhinostomy. In febrile and ill-appearing patients with acute dacryocystitis, hospitalization for intravenous antibiotics (cefuroxime) is indicated.

In infants with chronic dacryocystitis, both topical and oral antibiotics may be used. Referral is indicated if signs do not regress by 6 to 9 months of age or if acute dacryocystitis develops.

Clinical Pearls

1. The swelling is localized to the extreme nasal aspect of the lower lid and is usually unilateral.

2. The diagnosis of acute dacryocystitis may be confirmed by pressure on the lacrimal sac and the expression of purulent material from the punctum. The lacrimal sac and lacrimal fossa are situated in the inferior medial aspect of the orbit, not on the side of the nose.

3. The incidence follows a bimodal distribution. Dacryocystitis usually occurs in infants or persons over 40 years of age.

Dacryoadenitis

Associated Clinical Features

Dacryoadenitis is an uncommon condition involving inflammation of the lacrimal gland. Most acute cases are associated with systemic infection, although this may not be readily apparent. Findings are localized to the outer one-third of the upper eyelid and include fullness or swelling, conjunctival chemosis, and injection laterally (Fig. 2.16), erythema, and tenderness. A characteristic "S"-shaped deformity with mechanical ptosis of the upper lid is seen. The lacrimal gland may be palpable. Painful ophthalmoparesis and diplopia may be present secondary to involvement of the adjacent lateral rectus muscle.

Figure 2.16

Dacryoadenitis Unilateral localized swelling and chemosis are present laterally secondary to inflammation of the lacrimal gland. (Used with permission from the American Academy of Ophthalmology: External Disease and Cornea: A Multimedia Collection. San Francisco, 1994.)

Conditions associated with dacryoadenitis include sarcoidosis and Sjögren's syndrome. Infectious causes are more frequent; they include gonorrhea and mumps. Lacrimal gland masses, including lymphoma and epithelial tumors, may be neoplastic.

Differential Diagnosis

Chalazion, conjunctivitis, preseptal cellulitis, orbital cellulitis, and lacrimal gland tumor are other conditions to consider.

Emergency Department Treatment and Disposition

In the setting of acute bacterial infection, oral antibiotics (amoxicillin-clavulanate) are given for mild to moderate cases. In moderate to severe infections, intravenous antibiotics (ticarcillin-clavulanate) may be necessary. Viral dacryoadenitis (mumps) is treated with cool compresses and analgesics (acetaminophen); it resolves spontaneously without sequelae. Nonemergent ophthalmology follow-up is appropriate. Patients should be instructed to return to the ED urgently for symptoms suggestive of orbital cellulitis (decreased ocular motility or proptosis).

Clinical Pearls

1. The swelling is usually unilateral and localized over the lateral one-third of the upper lid. It imparts an "S"-shaped curve to the lid margin.

2. In children, acute dacryoadenitis is most often seen as a complication of mumps with accompanying bilateral parotid swelling.

3. Approximately half of lacrimal gland masses are inflammatory; the other half are neoplastic.

Pinguecula/Pterygium

Associated Clinical Features

A pinguecula (Latin: pinguecula meaning fatty) is a common degenerative lesion of the bulbar conjunctiva. It appears as a light brown or yellow-white amorphous conjunctival tissue adjacent to the limbus, usually nasally (Fig. 2.17). A pinguecula is usually asymptomatic and generally does not require treatment. It may become episodically inflamed, gradually enlarge over time, or become a pterygium.

Figure 2.17

Pinguecula A small area of yellowish "heaped up" conjunctival tissue is seen adjacent to the limbus on the nasal aspect. (Courtesy of Kevin J. Knoop, MD, MS.)

A pterygium (Greek: pterygion meaning a wing-like thing) is a benign proliferation of fibrovascular tissue. It originates within the bulbar conjunctiva and extends onto the peripheral cornea. Early in its course a pterygium may be indistinguishable from a pinguecula. It may then enlarge to progressively encroach onto the cornea and visual axis. Typically a pterygium assumes a triangular configuration, with the apex of the lesion directed toward the pupil (Fig. 2.18). Growth occurs from this apex. Risk factors include exposure to ultraviolet light (sunlight), wind, and dust. Pterygia and pingueculae are generally seen in older individuals living in warmer areas with high levels of sunlight. Like pingueculae, pterygia are more likely to involve the nasal portion of the bulbar conjunctiva. Pterygia may be asymptomatic or become inflamed, giving rise to mild symptoms of irritation and foreign-body sensation. Decreased visual acuity may develop if the visual axis is involved or if the lesion induces astigmatism (irregular corneal curvature resulting in refractive error).

Figure 2.18

Pterygium This pterygium appears as a raised vascular triangular area of bulbar conjunctiva that encroaches on the cornea. (Courtesy of the Department of Ophthalmology, Naval Medical Center, Portsmouth, VA.)

Differential Diagnosis

A pseudopterygium may have a similar appearance. A pseudopterygium is a fibrovascular scar arising in the bulbar conjunctiva and extending onto the cornea. It is the result of previous ocular inflammation (e.g., chemical burns, trauma, and infection). Episcleritis, corneal ulcer, and conjunctival neoplasm should be considered in the differential diagnosis.

Emergency Department Treatment and Disposition

A patient with mild disease can be treated with artifical tears or a topical vasoconstrictor (Vasocon). In more severe cases, topical steroids may be prescribed after consultation. Nonemergent referral to an ophthalmologist is appropriate. Excision of a pinguecula (or pterygium) is indicated if the lesion interferes with contact lens wear, becomes chronically inflamed, or constitutes a cosmetic problem. Pterygia are excised if they cause persistent discomfort, encroach significantly on the cornea to involve the visual axis, or restrict the movement of extraocular muscles.

Clinical Pearls

1. Pterygia and pingueculae are usually found on the nasal conjunctiva, adjacent to the limbus, in the horizontal meridian.

2. Pterygia are a particular problem in sunny, hot, dusty regions. Eye protection (goggles, sunglasses) helps to reduce the irritation.

Scleritis

Associated Clinical Features

Scleritis is a destructive and serious inflammation involving the sclera. The sclera is the tough, flexible white outer covering of the eye, composed of collagen and elastic fibers. The onset of scleritis is gradual. Pain, tearing, and photophobia are prominent features. The pain, frequently severe, may awaken the patient at night. It may radiate to the forehead, temple, brow, or jaw. Ocular movement is usually painful.

Patients with scleritis have an intensely red eye with a violaceous or purple hue, secondary to engorgement of the deep vessels of the episclera (Fig. 2.19). The blood vessels of the conjunctiva and superficial episclera are also commonly involved. Sectorial (versus diffuse) scleritis may mimic episcleritis. However, in scleritis, the globe is tender to palpation and the deep episcleral vessels do not move when the overlying tissues are moved with a cotton-tipped applicator, nor do they blanch with topical phenylephrine (2.5%). The normal radial vascular pattern of the episcleral vessels is lost. Scleral edema may be seen with slit-lamp biomicroscopy. (After the topical application of phenylephrine, the slit-lamp light beam appears to bow forward as the beam makes its excursion across the scleral surface.) Corneal involvement, iritis (with cells and flare in the anterior chamber) and decreased visual acuity frequently accompany scleritis. In patients with a previous history of scleritis, the uveal layer may be visible ("uveal show") in areas where scleral tissue has been lost.

Figure 2.19

Scleritis A prominent generalized vascular injection is present. These vessels do not move when the overlying conjunctiva is moved with a cotton-tipped applicator. (Courtesy of Thomas F. Mauger, MD.)

Scleritis is associated with a number of autoimmune and infectious conditions; rheumatoid arthritis is the most common. Scleritis occurs more frequently in women and in the fourth to sixth decades of life.

Differential Diagnosis

Other causes of a red eye (conjunctivitis, iritis, episcleritis, trauma, glaucoma) should be considered. Scleritis may be confused with an inflamed pinguecula, pterygium, foreign body, or tumor.

Emergency Department Treatment and Disposition

Ophthalmology consultation and systemic therapy are required. Oral nonsteroidal anti-inflammatory drugs (NSAIDs) are recommended. Systemic steroids are added if oral NSAIDs are ineffective or for severe scleritis. Topical steroids and NSAIDs are occasionally effective. Immunosuppressive therapy (cyclophosphamide, methotrexate, azathioprine) is sometimes required, especially for progressive cases. Appropriate treatment of associated systemic autoimmune disease is also important. The intraocular pressure should be measured, since secondary glaucoma is associated with scleritis.

Clinical Pearls

1. Scleritis—unlike episcleritis, which may be self-limited—is destructive and threatens the patient's vision.

2. The eye is usually exquisitely tender, and patients frequently complain of severe pain. Episcleritis, on the other hand, is rarely associated with significant pain or tenderness.

3. Scleritis may be the presenting sign of a systemic disease. Rheumatoid arthritis is the most common.

Episcleritis

Associated Clinical Features

Episcleritis is a common, benign, and frequently recurring inflammatory disease of the episclera; it typically affects young adults. The episclera is a thin layer of vascular elastic tissue overlying the primarily avascular sclera and is partly responsible for scleral nutrition. Tenon's capsule, a superficial layer within the episclera, acts as a synovial membrane for smooth movement of the eye. Episcleral vessels are large, run in a radial direction, and can be seen beneath the conjunctiva. Two separate vascular plexuses are found within the episclera. The superficial episcleral plexus is inflamed in episcleritis. These vessels blanch with the use of topical 2.5%phenylephrine drops. Vessels in the deep episcleral plexus, on the other hand, are associated with scleritis and remain dilated after the use of such drops.

Patients may complain of mild pain, foreign-body sensation, mild tenderness, irritation, photophobia, and excessive lacrimation. The affected eye appears normal except for nodular (or, rarely, diffuse) pink or bright red conjunctival and episcleral inflammation from dilation of the vessels in the superficial episcleral vascular plexus (Fig. 2.20). Visual acuity is normal. There is no history of trauma or purulent discharge.

Figure 2.20

Episcleritis A localized area of hyperemia consistent with episcleritis is seen in the lower lateral quadrant of the eye. (Courtesy of Thomas F. Mauger, MD.)

Episcleritis is usually an isolated condition and the etiology is unknown. It has been associated with gout, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, and herpes zoster.

Differential Diagnosis

Other considerations include conjunctivitis and other causes of a red eye, such as iritis, acute glaucoma, trauma, corneal ulcer, scleritis, pinguecula, and phlyctenule (similar to episcleritis except that a nodule is present in the center of the lesion).

Emergency Department Treatment and Disposition

In mild cases, the condition is self-limited and may resolve spontaneously after 1 to 2 weeks. Artificial tears and topical vasoconstrictors (Naphcon) may be used. In those cases associated with rheumatoid arthritis or systemic lupus erythematosus, oral NSAIDs are recommended. Topical NSAIDS have not been shown to be effective. Ophthalmology referral is appropriate for confirmation and treatment.

Clinical Pearls

1. It is important to distinguish between episcleritis and scleritis, because the latter is an extremely serious problem that threatens the patient's vision.

2. While other causes of a red eye demonstrate a generalized redness, episcleritis is usually localized.

3. Dilated vessels in the superficial episcleral plexus will blanch with topical 2.5% phenylephrine. This test helps to distinguish between episcleritis and scleritis.

4. Episcleritis is unilateral two-thirds of the time and is seen in young and middle-aged adults. The gender incidence is equal.

5. Topical corticosteroids are not indicated in episcleritis. Although they may be effective temporarily, their use prolongs the natural history of resolution.

Acute Angle Closure Glaucoma

Associated Clinical Features

Glaucoma comprises a heterogeneous group of disorders causing optic nerve damage, usually in association with elevated intraocular pressure (IOP). It is a major and preventable cause of blindness. In angle closure glaucoma (ACG), the elevated IOP is due to an outflow obstruction of aqueous humor from the anterior chamber. Aqueous humor is initially produced by the ciliary body and first enters the posterior chamber. It then passes between the posterior surface of the iris and the anterior surface of the lens to enter the anterior chamber. After circulating within the anterior chamber, the aqueous humor leaves through the trabecular meshwork of the anterior chamber angle to enter Schlemm's canal. In ACG, the peripheral iris covers this trabecular meshwork, the angle is "closed," and aqueous outflow is blocked. Normal IOP is 10 to 21 mmHg; it rises to 50 to 100 mmHg in ACG.

There are several anatomic and physiologic factors that play a role in ACG. In the most common type of ACG, a major role is played by relative pupillary block. As the lens slowly enlarges due to normal development and aging, more of the lens's anterior surface makes contact with the iris's posterior surface. This increases the relative block of aqueous humor flow from the posterior chamber through the pupil to the anterior chamber. As a result, an increased pressure differential develops. The increased pressure in the posterior chamber causes the iris to bulge anteriorly ("iris bombé"). This bulging of the iris is maximal when the pupil is in the middilated position, generally 3 to 6 mm in diameter. The major factor that seems to predispose to an acute attack of ACG is prolonged, stationary middilation of the pupil. This sustained middilation can be seen with prolonged awake exposure to dim light or darkness with relaxation of the sphincter muscle, topical or systemic pharmacologic therapy that dilates the pupil, or prolonged severe emotional stress with secondary dilation due to adrenergic stimulation of the dilator muscle.

ACG presents as an acutely inflamed eye. Eye pain or headache varies in severity. Nausea and vomiting are common and may be the presenting complaints. As the IOP reaches the range of 50 to 60 mmHg, fluid is forced into the normal cornea, resulting in corneal edema. Because of this, patients may report blurred vision and rainbow-colored halos around lights. Clinical findings on examination include tearing, conjunctival injection with a perilimbal ("ciliary") flush, a cloudy ("steamy") cornea (Fig. 2.21), a nonreactive and middilated pupil (Fig. 2.22), mild anterior chamber inflammation, and increased intraocular pressure. Also, the anterior chamber is shallow. This is demonstrated by a penlight held laterally and directed nasally (Fig. 2.23). In an eye with a normal anterior chamber, the entire iris will be illuminated by the penlight. In an eye with a narrow angle or shallow anterior chamber, a shadow is cast on the nasal side of the iris secondary to the forward bowing of the iris. Alternatively, slit-lamp biomicroscopy may also be used to assess the anterior chamber's depth. Funduscopic examination demonstrates optic cupping only if there is preexisting glaucoma.

Figure 2.21

Acute Angle Closure Glaucoma The cornea is edematous, manifest by the indistinctness of the iris markings and the irregular corneal light reflex. Conjunctival hyperemia is also present. (Courtesy of Kevin J. Knoop, MD, MS.)

Figure 2.22

Acute Angle Closure Glaucoma Note the cloudy or "steamy" appearance of the cornea and the midposition pupil. Conjunctival hyperemia is not as evident. (Courtesy of Gary Tanner, MD.)

Figure 2.23

Penlight Test A penlight, held laterally and directed nasally, projects a shadow on the nasal side of an iris with a shallow anterior chamber. This patient presented with acute angle closure glaucoma. (Courtesy of Alan B. Storrow, MD.)

Tonometers available in the ED for measurement of IOP include the air-puff noncontact tonometer, the Schiøtz tonometer, the Tono-Pen, and the applanation tonometer. Tactile tonometry, using the examiner's fingers to ballot the globe, can easily detect ACG in patients with markedly elevated IOP.

Differential Diagnosis

Similar conditions include temporal arteritis, acute iritis, ulcer, and other causes of a red eye (conjunctivitis, trauma, scleritis, keratitis, foreign body).

Emergency Department Treatment and Disposition

ACG requires emergent ophthalmology consultation. Treatment is directed at reducing the IOP. Aqueous outflow is increased by the use of topical miotics (pilocarpine 1 or 2%, one drop every 5 min x 2. If the pupil does not respond, one drop every hour x 4 should be administered.) Topical miotics such as pilocarpine stimulate miosis to pull the peripheral iris taut, away from the trabecular meshwork. If the pupil does not respond within 5 to 10 min (or if it is not expected to respond because the IOP is greater than 50 to 60 mmHg or the attack is many hours old), other medications with a different mechanism of action to decrease the IOP should be administered. Decreased production of aqueous is accomplished with the use of a topical beta blocker (timolol maleate, 0.5%, one drop every 12 h) or an alpha-adrenergic agonist (apraclonidine, 1%, one drop every 12 h). Acetazolamide, a carbonic anhydrase inhibitor, can also be given (500 mg PO or 500 mg IV if the patient is nauseated or vomiting). The goal of these medicines, which decrease the production of aqueous, is to rapidly lower the IOP to less than 40 to 50 mmHg so as to allow for reperfusion of the pupillary sphincter, thereby permitting the muscle to respond to pilocarpine. Osmotic agents may also be used. Oral agents are tried first; if they are unsuccessful or if the patient is nauseous, systemic intravenous agents may then be used. Oral agents include glycerol (1.0 to 1.5 g/kg in a 50% solution). In diabetics, since glycerol can cause hyperglycemia, oral isosorbide can be substituted (1.5 to 2.0 g/kg). Intravenous agents include mannitol (20% solution, 2 g/kg given over 30 min). Hyperosmotics realize their maximal reduction within 45 to 60 min. A final agent to consider for use in ACG is the prostaglandin derivative latanoprost (0.005%, one drop once daily in the evening). Its mechanism of action is increased uveal-scleral outflow, acting to increase aqueous outflow through nontrabecular meshwork pathways.

Corneal indentation may be used in situations where the IOP is 50 mmHg or greater and topical miotics are ineffective secondary to ischemia of the iris constrictor. Indentation of the cornea displaces the aqueous to the peripheral anterior chamber, temporarily opening the angle. Corneal indentation is performed with topical anesthetics and any smooth instrument such as the Goldmann applanation prism. The prism is held with the fingers and firm pressure is applied for 30 s. This may successfully decrease the IOP and abort the attack; if the IOP has been of long standing, however, it is more likely to be unsuccessful.

The definitive treatment of ACG is laser peripheral iridectomy, usually done after the IOP normalizes.

Clinical Pearls

1. ACG may be inadvertently precipitated in the ED patient treated for corneal abrasion with a cycloplegic (cyclopentolate). Therefore the depth of the anterior chamber should always be evaluated in ED patients receiving cycloplegics.

2. In light of the associated severe headache and vomiting, patients with ACG may easily be misdiagnosed as having a migraine headache or a central nervous system (CNS) catastrophe.

3. The unaffected eye will also have a narrow anterior chamber. The presence of a shallow anterior chamber in only one eye casts doubt on the diagnosis of ACG, since ACG is the result of an anatomic configuration that is almost always bilateral.

4. Patients with ACG may be able to recall a previous (milder) attack that they felt was a migraine or some other type of headache.

5. The elevated IOP in acute ACG can be reduced pharmacologically by three mechanisms: first, by opening the closed angle with miotics; second, by reducing aqueous formation with beta blockers, alpha agonists, and carbonic anhydrase inhibitors; and third, by reducing the aqueous volume within the eye using osmotic agents.

Anterior Uveitis (Iritis)

Associated Clinical Features

The uvea is the middle layer of the eye and is composed of the iris, ciliary body, and choroid. Uveitis refers to inflammation within the uvea, and anterior uveitis localizes the inflammation to the anterior chamber, iris, ciliary body, and anterior vitreous.

In many cases of anterior uveitis, no definitive diagnosis can be made. A significant number, however, are associated with medically treatable systemic diseases. The list is extensive and includes inflammatory disorders (juvenile rheumatoid arthritis, rheumatoid arthritis, sarcoidosis, Behçet's disease, Sjögren's syndrome), conditions associated with HLA-B27, (ankylosing spondylitis, inflammatory bowel disease, Reiter's syndrome), and infectious diseases (tuberculosis, toxoplasmosis, herpes simplex, herpes zoster, cytomegalovirus, syphilis, AIDS). Finally, lymphoma and Kawasaki's disease may also manifest as an anterior uveitis. Therefore aggressive attempts to determine the underlying cause of the uveitis are warranted.

Clinical features of anterior uveitis include conjunctival hyperemia, hyperemic perilimbal vessels ("ciliary flush") (Fig. 2.24), decreased visual acuity, photophobia, miosis, pupillary irregularities (secondary to the formation of anterior or posterior synechiae), iris nodules, tearing (particularly when exposed to bright lights), and pain. A hypopyon (a layer of white blood cells in the dependent portion of the anterior chamber) may be seen (Fig. 2.25). The slit-lamp examination may demonstrate cells and flare. Cells refers to the finding of inflammatory cells seen in the anterior chamber, having the appearance of dust in a sunbeam (Fig. 2.26); flare is light scatter secondary to inflammatory cells and proteins circulating within the aqueous and anterior chamber and has the appearance of a headlight in fog (Fig. 2.27). Other significant slit-lamp findings in anterior uveitis include keratic precipitates, which are agglutinated inflammatory cells adherent to the posterior corneal endothelium (Fig. 2.28). Keratic precipitates appear either as fine gray-white deposits or as large, flat, confluent areas with a greasy surface ("mutton fat"). The intraocular pressure (IOP) may be elevated secondary to inflammatory debris within the trabeculae, obstructing outflow, or the IOP may be decreased secondary to decreased production of aqueous humor by the inflamed ciliary body.

Figure 2.24

Anterior Uveitis Marked conjunctival injection and perilimbal hyperemia ("ciliary flush") are seen in this patient with recurrent iritis. (Courtesy of Kevin J. Knoop, MD, MS.)

Figure 2.25

Hypopyon A thin layering of white blood cells is present in the inferior anterior chamber. (Used with permission from Spalton DJ, Hitchings RA, Hunter PA (eds): Atlas of Clinical Ophthalmology, 2d ed. Mosby-Wolfe Limited, London, UK, 1994.)

Figure 2.26

Anterior Chamber Cells Cells in the anterior chamber are a sign of inflammation or bleeding and appear similar to particles of dust in a sunbeam. They are best seen with a narrow slit-lamp beam directed obliquely across the anterior chamber. (Used with permission from Spalton DJ, Hitchings RA, Hunter PA (eds): Atlas of Clinical Ophthalmology, 2nd ed. Mosby-Wolfe Limited, London, UK, 1994.)

Figure 2.27

Anterior Chamber Flare Flare in the anterior chamber represents an elevated concentration of plasma proteins from inflamed, leaking intraocular blood vessels. Flare seen in a slit-lamp beam appears similar to a car headlight cutting through the fog. (Used with permission from Spalton DJ, Hitchings RA, Hunter PA (eds). Atlas of Clinical Ophthalmology. Mosby-Wolfe Limited, London, UK, 1984.)

Figure 2.28

Keratic Precipitates Deposits of cells on the endothelial layer of the cornea are seen in these photographs. (Used with permission from Spalton DJ, Hitchings RA, Hunter PA (eds): Atlas of Clinical Ophthalmology, 2nd ed. Mosby-Wolfe Limited, London, UK, 1994.)

Differential Diagnosis

Other conditions presenting with a red eye include glaucoma, conjunctivitis (bacterial, viral, allergic), scleritis, episcleritis, keratitis, and corneal ulcer. A hypopyon can also be seen with severe corneal ulcerations and penetrating trauma to the anterior chamber.

Emergency Department Treatment and Disposition

In light of the common association of anterior uveitis with systemic disease, the evaluation of a uveitis patient in the ED is a systemic evaluation. The history should focus on rheumatic illness, dermatologic problems, bowel disease, infectious exposures, and sexual history. This history forms the basis for the subsequent physical examination and laboratory testing.

Treatment of the anterior uveitis itself is nonspecific. Topical cycloplegics (atropine) and corticosteroids may be prescribed in conjunction with the ophthalmologist. Although nonspecific, this therapy will greatly reduce the amount of scarring. Antibiotics are not usually prescribed or helpful unless there is a bacterial origin. Prompt ophthalmology follow-up is important if steroids are prescribed.

Clinical Pearls

1. Key diagnostic features of anterior uveitis are a miotic pupil, ciliary flush, and the finding of cells and flare in the anterior chamber.

2. When cells and flare are visualized in the anterior chamber using the slit lamp, the cells look like dust particles in a sunbeam, and the flare (the slit-lamp beam) looks like a headlight cutting through fog.

3. Inflammation of the anterior uveal tract (iris or ciliary body) produces the clinical symptom of photophobia.

4. The presence of anterior uveitis requires a search for associated systemic illness.

5. Topical analgesics (tetracaine, proparacaine) do not significantly ameliorate the pain of anterior uveitis, unlike the case with many of the common conditions seen in the ED, such as corneal abrasions.

6. The discharge associated with anterior uveitis is watery or nonexistent. A purulent discharge suggests an infectious condition such as conjunctivitis or keratitis.

Herpes Zoster Ophthalmicus

Associated Clinical Features

Herpes zoster ophthalmicus develops secondary to activation of latent varicella zoster virus within the trigeminal ganglion. Neuronal spread of the virus through the ophthalmic division of the trigeminal nerve results in crops of grouped vesicles in a dermatomal distribution (Fig. 2.29).

Figure 2.29

Herpes Zoster Ophthalmicus A healing vesicular rash in the distribution of the ophthalmic division (V1) of the trigeminal nerve is present in this 72-year-old diabetic patient. The presence of the lesion on the tip of the nose (Hutchinson's sign) increases the risk of ocular involvement. (Courtesy of Frank Birinyi, MD.)

Almost any ophthalmic abnormality in both the anterior and posterior segments of the eye may be seen with herpes zoster ophthalmicus. The most common corneal lesion is punctate epithelial keratitis, in which the cornea has a ground-glass appearance because of stromal edema. Pseudodendrites are also very common. Pseudodendrites form from the deposition of mucus, are usually peripherally located and stain moderately to poorly with fluorescein. Pseudodendrites may be differentiated from the dendrites of herpes simplex infection in that the pseudodendrites lack the rounded terminal bulbs at the end of the branches and are broader and more plaque-like. When they are wiped from the cornea, a layer of intact epithelium may remain, unlike the full-thickness epithelial defect seen with herpes simplex. The third most common corneal lesion—after punctate epithelial keratitis and pseudodendrites—is that of anterior stromal infiltrates. These are seen between the second and third weeks after the acute disease and are felt to be an immune response to viral antigen diffusing into the anterior stroma. They may be single or multiple.

Corneal anesthesia or hypoesthesia is a frequent complication of herpes zoster keratitis. Some 60% of patients will recover essentially normal sensitivity within 2 to 3 months. In about 25%, however, the anesthesia is permanent.

The anterior uvea is commonly involved in herpes zoster ophthalmicus and is second only to the cornea in frequency of involvement. Anterior uveitis may develop early or years after the acute disease—and independent of corneal pathology. Clinical findings range in severity and include ciliary flush, miosis, pain, cells and flare in the anterior chamber, photophobia, visual decrease, keratic precipitates (agglutinated inflammatory cells adherent to the posterior corneal endothelium), and anterior and posterior synechiae (adhesions from the iris to the cornea anteriorly or to the lens posteriorly).

Conjunctivitis is also extremely common; it is characterized by a watery discharge. Follicles (hyperplastic lymphoid tissue that appears as gray or white lobular elevations, particularly in the inferior cul-de-sac) and regional adenopathy may or may not be present.

Differential Diagnosis

Keratitis secondary to herpes simplex may also present with rash, red eye, and dendriform corneal lesions. Ocular complications of herpes zoster ophthalmicus may follow the rash by many months to years; they have a highly variable presentation that can mimic almost any ophthalmic disease.

Emergency Department Treatment and Disposition

In patients with epithelial defects, topical broad-spectrum antibiotics should be administered bid to prevent secondary infection. Oral valacyclovir (1 g three times a day for 7 days), famciclovir (500 mg three times a day for 7 days), or acyclovir (800 mg five times a day for 10 days) is beneficial, particularly if given within 72 h of onset. Topical antivirals are clinically ineffective. Cycloplegics (cyclopentolate) are used if an iritis is present. Artificial tears and ointment may be recommended to the patient as necessary. Nonnarcotic and narcotic analgesics may be prescribed. An ophthalmology consult is appropriate.

Steroids in the past (before acyclovir) were among the mainstays of treatment. However, steroids have proved less successful than systemic acyclovir, famciclovir, and valacyclovir. Also arguing against steroid use is the risk of systemic dissemination of the herpes zoster virus should the zoster be an early presenting sign of immunosuppression. Therefore systemic steroids are largely out of favor.

Clinical Pearls

1. Nearly two-thirds of patients with herpes zoster ophthalmicus develop ocular lesions; thus careful eye examination with corneal staining should be performed to rule out corneal involvement.

2. Patients with skin lesions on the tip of the nose (Hutchinson's sign) are at higher risk for ocular involvement with herpes zoster. The sensory innervation to both the eye and the tip of the nose is supplied by the nasociliary branch of the ophthalmic division of cranial nerve V. This sign, however, is highly variable in its reliability. The eye may be involved without nasal involvement.

3. Corneal hypoesthesia and the appearance of dendrites with fluorescein staining are seen in both herpes zoster ophthalmicus and herpes simplex keratitis.

4. The severity of the cutaneous disease does not necessarily correlate with the severity of the ocular disease.

5. The prognosis is good, and recurrences—unlike those for herpes simplex keratitis—are rare.

Ocular Herpes Simplex

Associated Clinical Features

Ocular herpetic disease may be neonatal, primary, or recurrent. Neonatal ocular herpes develops secondary to passage through an infected birth canal. Usually (80%) is herpes simplex virus (HSV) type 2. Most frequently the infection is a conjunctivitis, often associated with a keratitis. Fetal monitoring with a scalp electrode is associated with an increased risk for neonatal HSV infection.

Primary ocular herpes is an acute first HSV infection of a nonimmune host. It may present as blepharitis (vesicles on an erythematous base), conjunctivitis, or keratoconjunctivitis. Clinical disease may be seen 3 to 9 days after exposure. Patients with keratoconjunctivitis commonly have significant periorbital skin involvement. They note pain, irritation, foreign-body sensation, redness, photophobia, tearing, and occasionally decreased visual acuity. Follicles and preauricular adenopathy may be seen. Initially the keratitis is diffuse and punctate. After 24 h, fluorescein stain appears as either serpiginous ulcers without clear-cut branching or multiple diffuse microdendritic epithelial defects. True dendritic ulcers are rarely seen in primary disease.

The most likely clinical scenario facing the ED physician in cases of ocular herpes simplex is that of recurrent disease. Recurrences may be triggered by immunosuppression, fever, ultraviolet light exposure, trauma, systemic illness, stress, or menstruation. In recurrent disease, keratoconjunctivitis (Fig. 2.30), blepharitis, or iritis is seen, and the cornea is more likely to be involved (Fig. 2.31). With blepharitis and recurrent HSV disease, vesicles are grouped in focal clusters, with significantly less skin involvement than that seen in primary herpes. In those patients with recurrent HSV and keratoconjunctivitis, signs and symptoms include a watery discharge, conjunctival injection, irritation, blurred vision, and preauricular lymph node involvement. Corneal involvement initially may appear punctate but evolves into a characteristic dendritic keratitis (Figs. 2.32, 2.33). Dendritic ulcers may be single or multiple. Their linear branches classically end in bead-like extensions called terminal bulbs. These are best seen with rose Bengal stain, which stains the epithelial defect as well as the infected cells surrounding the defect (Fig. 2.34). Fluorescein dye demonstrates primarily the corneal defect; punctate staining may be appreciated over the surrounding damaged epithelium. In addition to the dendritic pattern, fluorescein staining may instead take on a geographic appearance. This is particularly true when topical steroids have been (incorrectly) prescribed. Most patients (80%) with herpes simplex keratitis have decreased or absent corneal sensation in the area of the dendrite or geographic ulceration. Uninvolved areas of the cornea may retain normal sensation.

Figure 2.30

Herpes Simplex Keratitis This 23-year-old has a history of ocular herpes infections since childhood. Grouped vesicles on an erythematous base with mild lid swelling are seen. The conjunctiva is mildly hyperemic. (Secondary impetigo may be present.) (Courtesy of Frank Birinyi, MD.)

Figure 2.31

Herpes Simplex Keratitis A slit-lamp view of unstained dendritic lesions. (Courtesy of Lawrence B. Stack, MD.)

Figure 2.32

Herpes Simplex Keratitis A large dendritic lesion after fluorescein staining. The patient had been diagnosed with "pink eye" in a prior visit. (Courtesy of Kevin J. Knoop, MD, MS.)

Figure 2.33

Herpes Simplex Keratitis A magnified view via slit-lamp biomicroscopy shows the classic terminal bulbs pathognomonic for ocular HSV infection. (Courtesy of Department of Ophthalmology, Naval Medical Center, Portsmouth, VA.)

Figure 2.34

Herpes Simplex Keratitis Fluorescein (left) and rose Bengal (right) stains demonstrate characteristic dendritic patterns. Whereas fluorescein staining is used to detect epithelial defects, rose Bengal staining additionally demonstrates degenerating or dead epithelial cells and is particularly good for demonstrating the club-shaped terminal bulbs at the end of each branch. (Used with permission from the American Academy of Ophthalmology: External Disease and Cornea: A Multimedia Collection, San Francisco, 1994.)

Following protracted and repeated episodes of HSV keratitis, corneal lesions occasionally scar, and a permanently decreased visual acuity can result. In some patients, melting and perforation of the cornea ensue secondary to structural damage.

Differential Diagnosis

Other causes of red eye (scleritis, iritis, glaucoma, conjunctivitis) should be considered. A similar fluorescein appearance may be seen with herpes zoster virus, recurrent corneal erosions, or a healing corneal abrasion.

Emergency Department Treatment and Disposition

In neonatal ocular herpes infections, an emergency pediatric or infectious disease consultation is initiated. There is a high association between ocular neonatal HSV infection and potentially lethal systemic or neurologic infection. Therefore acyclovir is given intravenously. The ocular disease itself may be treated with topical antivirals (idoxuridine, vidarabine, trifluorothymidine).

Treatment of patients (beyond the neonatal period) with primary ocular herpes is usually successful and generally results in healing without scarring. For those with blepharitis or periocular dermatitis, warm wet soaks bid and general good hygiene is recommended. A prophylactic topical antiviral (trifluorothymidine drops five times a day, idoxuridine ointment tid or idoxuridine drops eight times a day) is administered to the adjacent eye until the skin lesions scab and dry. Patients with corneal involvement require a 2- to 3-week course of antiviral ointment or drops (trifluorothymidine 1% nine times a day, or idoxuridine 0.1% either q 1 h by day, q 2 h at night, or 1 drop q 5 min x 5 five times daily). Topical antibiotics bid are also recommended for those with corneal lesions to prevent secondary bacterial infection.

In patients with recurrent disease limited to HSV blepharitis, the lesions are superficial and heal without scarring. The goal of therapy in these patients is to protect the globe with prophylactic antiviral ointment tid or drops five to six times a day until the lesions have scabbed. No clinical trials have demonstrated oral acyclovir to prevent herpetic blepharitis. Nevertheless initiating acyclovir 400 mg PO five times a day for 5 days within 1 h of the first sign of recurrence is recommended and may alleviate some symptoms.

For most patients with recurrent HSV disease and corneal involvement, topical antivirals alone are effective. Trifluorothymidine (1% nine times a day for 14 to 21 days) is recommended. Topical antibiotics are administered bid while a corneal defect is present. Ophthalmology consultation is required.

Clinical Pearls

1. The diagnosis of acute neonatal ocular HSV should be entertained in any infant with nonpurulent conjunctivitis or keratitis.

2. HSV is the most common cause of corneal ulceration and the most common infectious cause of corneal blindness in the western hemisphere.

3. HSV dendrites, when stained with fluorescein, appear as branching lesions with club-shaped or bead-like extensions called terminal bulbs at the end of each branch. In primary HSV disease, however, dendrites are rare. Terminal bulbs are not seen in herpes zoster dendrites.

4. Other patterns of fluorescein staining in HSV infection include a superficial punctate keratitis. This is seen particularly in primary disease and early in the course of recurrent disease.

5. With recurrent attacks, corneal pain may be diminished owing to increasing corneal hypoesthesia.

Corneal Ulcer

Associated Clinical Features

The term corneal ulcer denotes an inflammatory and ulcerative condition. Similar terms include infectious keratitis, bacterial keratitis, and ulcerative keratitis. Etiologies include bacteria (most commonly Staphylococcus, Streptococcus, and Pseudomonas) and viruses (herpes simplex). (Keratitis secondary to herpes simplex is discussed separately.) Bacterial corneal ulcers are commonly associated with extended-wear soft contact lenses and contaminated lens care solutions (Fig. 2.35), whereby minor corneal abrasion or chemical damage permits bacteria to penetrate the cornea. Fungal infection, although rare, should be suspected in cases of ocular trauma involving vegetable matter (a tree branch), chronic corneal disease (herpes keratitis), or cases involving steroid use. Acanthamoeba keratitis is associated with contaminated contact lens solutions.

Figure 2.35

Corneal Ulcer An elliptical ulcer at 5 o'clock near the periphery is seen. This location is atypical for a bacterial ulcer. The patient presented with painful red eyes and normal uncorrected vision, but was a new wearer of soft contact lenses (for cosmesis). Bilateral corneal ulcers were diagnosed, which cleared after treatment with topical cipro-floxacin. The impressive ciliary flush is pathognomonic for corneal (versus conjunctival) pathology. (Courtesy of Kevin J. Knoop, MD, MS.)

Symptoms associated with corneal ulcer include pain, photophobia, decreased vision, discharge, and a foreign-body sensation. The ulcer appears as a corneal stromal infiltrate associated with conjunctival hyperemia (Fig. 2.36), a miotic pupil, and chemosis along with lid edema and erythema. Slit-lamp biomicroscopy demonstrates an epithelial defect with fluorescein uptake. Findings in the anterior chamber include cells (inflammatory cells that look like dust in a sunbeam) and flare (light scatter seen secondary to cells and proteins), keratic precipitates (inflammatory cells that have coalesced and adhered to the cornea), and hypopyon (a layer of white blood cells in the inferior or dependent portion of the anterior chamber).

Figure 2.36

Corneal Ulcer A circular corneal infiltrate is seen at 12 o'clock; conjunctival hyperemia is present. (A rectangular flash reflection is seen at 9 o'clock.) A mild limbal flush is noted superiorly. (Courtesy of Lawrence B. Stack, MD.)

Differential Diagnosis

Other possibilities include a residual corneal foreign body, a rust ring, and a sterile corneal infiltrate (secondary to an immune reaction to contact lens solution or Staphylococcus). Other causes of a red eye (conjunctivitis, glaucoma, scleritis) should also be considered.

Emergency Department Treatment and Disposition

Corneal ulcers should be treated as an ophthalmologic emergency and assumed to be bacterial until proven otherwise. An emergent ophthalmology consult is indicated, and stains and cultures should be obtained as expeditiously as possible before antibiotic treatment has commenced. Intensive topical treatment is the most effective way to treat corneal infections. Fortified (concentrated) cephalosporins or vancomycin combined with an aminoglycoside may be used every 30 to 60 min. A fluoroquinolone may be used as a single agent for mild cases of infectious keratitis. Clinical improvement is usually noted after 2 to 3 days of therapy; the frequency of antibiotic instillation can then be tapered. Subconjunctival injections of antibiotics every 12 to 24 h are used in severe cases. Systemic antibiotics are not usually used except in cases where the organism may have extended to the sclera (Pseudomonas) or if there is a high risk of concurrent systemic disease (Neisseria, Haemophilus). Cycloplegics (atropine) are usually recommended if there is an accompanying iritis. Epithelial debridement may be beneficial. Steroids and an eye patch are contraindicated in the initial management. A contact lens wearer must discontinue contact lens wear.

Clinical Pearls

1. A bacterial corneal infection must be treated as an ophthalmologic emergency.

2. Corneal injury, including recent contact lens procedures, is a risk factor for the development of a corneal ulcer.

3. Pseudomonas aeruginosa is capable of destroying the cornea within 6 to 12 h. It should be suspected by its aggressive course, thick yellow-green or blue-green tenacious, mucopurulent exudate, and ground-glass edema surrounding the ulcer.

4. Acanthamoeba, a ubiquitous protozoan, should be suspected in contact lens wearers with contaminated lens solutions or who swim wearing their contact lenses. These patients characteristically have pain out of proportion to their clinical findings.

5. Infectious ulcers tend to develop centrally, away from the vascular supply and immune system of the limbus, but they can also be peripheral.

Anisocoria

Associated Clinical Features

Anisocoria is unequal pupil size. In room lighting, the normal diameter of pupils is 3 to 5 mm. Pupil size is larger in childhood and smaller with age. Anisocoria of 1 to 2 mm may be a normal finding, and is found in 5 to 20% of normal individuals. With normal (physiologic) anisocoria, the disparity in pupil size is the same in light as in dark. In addition, the pupils react normally to light and accommodation; they are perfectly round, extraocular movements are intact, and no ptosis or conjunctival injection is present.

Differential Diagnosis

Pupillary inequality is indicative of damage to one of the four iris muscles or their innervation. In order to establish which is the abnormal pupil, pupil sizes in light and dark should be compared. Anisocoria increases in the direction of action of the paretic iris muscle. If the iris sphincter muscle is paretic, its weakness will be accentuated in bright light, since reflex constriction is impaired. Conversely, if the iris dilator muscle is paretic, the anisocoria will be accentuated in darkness.

The most serious causes of anisocoria are neurogenic. In the setting of trauma, severe headache, or following intracranial surgery, anisocoria and a third-nerve palsy with ptosis, extraocular muscle palsies, and a nonreactive pupil are early signs of an aneurysm or an expanding supratentorial mass with tentorial herniation.

Other causes of anisocoria with an abnormally large pupil include an acute Adie's pupil, eye drops (atropine, phenylephrine, naphazoline), inadvertent contamination from a scopolamine patch, and ocular trauma with damage to the iris sphincter (Fig. 2.37). A patient with an Adie's pupil may note that he or she cannot focus with one eye, although the appearance of a dilated pupil is more likely to prompt the ED visit. An Adie's pupil is dilated secondary to impairment in the postganglionic nerve supply to the iris sphincter. Causes include orbital trauma, infection, herpes zoster, diabetes, autonomic neuropathies, and Guillain-Barré syndrome, but in most instances the cause is unknown. Although an Adie's pupil is initially dilated, it may become miotic over time. A dilated pupil that is secondary to atropine eye drops does not react to light. Sympathomimetics eye drops such as phenylephrine, on the other hand, dilate the pupil, but the pupil still has some response to light. In addition, the conjunctiva may be blanched and the lid retracted. The slit-lamp examination helps to differentiate drug-induced dilation from dilation secondary to Adie's pupil. When dilation is drug-induced, the entire sphincter muscle is affected, whereas in Adie's, a segmental palsy is seen. (Segmental palsy is best appreciated with slit-lamp biomicroscopy. The curvature of the pupillary margin in those sections of the iris with palsy appears flatter. In addition, active pupil constriction is not radially symmetric.) The patient with ocular trauma and damage to the iris sphincter may show, on slit-lamp examination, evidence of a torn iris, an irregularly shaped pupil, hyphema, or lens dislocation.

Figure 2.37

Normal Anisocoria Marked chronic anisocoria secondary to prior trauma. (Courtesy of Kevin J. Knoop, MD, MS.)

An abnormally small pupil may be secondary to Horner's syndrome (see Fig. 2.38), chronic Adie's pupil (8 weeks or more after the event), iritis, and eye drops (pilocarpine). Associated clinical findings in Horner's syndrome include mild to moderate ptosis. The patient with iritis usually demonstrates conjunctival injection with a ciliary flush. Unilateral miosis may be transiently observed after ocular injury, followed by the development of mydriasis. Miosis in the setting of ocular trauma is secondary to spasm of the pupillary sphincter muscle.

Emergency Department Treatment and Disposition

The evaluation of anisocoria in the ED is dependent on the clinical presentation. A patient with acute onset of a third-nerve palsy and associated headache or trauma should be aggressively evaluated and treated as a neurosurgical emergency.

Pilocarpine may be helpful to differentiate pharmacologic pupil dilation from other causes of an abnormally dilated pupil, such as Adie's pupil and third-nerve palsy. With low concentrations of pilocarpine (0.125%), an Adie's pupil will constrict significantly more than the unaffected pupil because of denervation supersensitivity. With higher concentrations (1%), a pupil will constrict even if there is a third-nerve palsy. A pupil that fails to constrict with 1% pilocarpine localizes the etiology to the iris sphincter muscle itself. In this situation, the most likely diagnosis is the use of topical anticholinergic mydriatics such as scopolamine, atropine, or cyclopentolate. Other problems within the iris sphincter muscle that prevent constriction to 1% pilocarpine include synechiae (causing a mechanically immobile iris) and trauma to the iris muscle.

Clinical Pearls

1. The patient who presents with a dilated pupil should undergo a careful examination for ptosis and abnormal extraocular muscle movements, since their presence suggests compressive damage to the intracranial third nerve by an aneurysm or mass.

2. Pupil sizes in light and dark should be compared. In physiologic or normal anisocoria, the disparity in pupil size is the same in light as in dark. Anisocoria that is greater in the dark suggests that the smaller pupil is abnormal due to paresis of its iris dilator muscle; anisocoria greater in the light suggests that the larger pupil is abnormal due to paresis of its iris sphincter muscle.

3. An old photograph or driver's license viewed with an ophthalmoscope may be helpful to document the prior existence of anisocoria.

4. Some brands of eye makeup contain belladonna alkaloids, which can cause mydriasis.

5. Adie's pupil initially is dilated but may become miotic over time. It is a benign condition that affects young adults, women more often than men.

Horner's Syndrome

Associated Clinical Features

Horner's syndrome consists of loss of ocular sympathetic innervation secondary to a lesion within the sympathetic pathway. This pathway can be interrupted in any location, from the hypothalamus down through the brainstem to the cervical cord, in the apex of the chest, along the carotid sheath, or in the cavernous sinus or orbit. Clinical features include unilateral miosis, along with mild to moderate unilateral ptosis (Fig. 2.38). Slight elevation of the lower lid may also be noted. Light and near reactions are intact. Acutely, conjunctival injection may be present on the affected side, and the intraocular pressure may be reduced. Anhidrosis of the ipsilateral face may be present, and the ipsilateral face may be warm and hyperemic. However, these findings are not present if the interruption of the sympathetic nerve supply occurs in a distal location, such as along the internal carotid artery. This is because vasoconstrictor fibers to the face, along with innervation to sweat glands, travel with branches of the external carotid artery.

Figure 2.38

Horner's Syndrome Unilateral miosis and ptosis are seen in this patient with Horner's syndrome and sarcoma metastatic to the spine. (Courtesy of Frank Birinyi, MD.)

A pupillary finding that is specific to Horner's syndrome is dilation lag. Normal pupil dilation is a combination of sphincter relaxation and dilator contraction, which produces a prompt dilation. A patient with Horner's syndrome, however, has a weak dilator muscle in one iris; as a result, that pupil dilates more slowly than the normal pupil. This anisocoria is maximal after 4 to 5 s. After 10 to 20 s, the anisocoria lessens, owing to the continued relaxation of the iris sphincter. Dilation lag is best seen if the patient is examined in a room where the lights can be turned off and a hand-held light illuminates the eyes from below.

Associated clinical findings are secondary to the neurologic lesion and its location. The causes of Horner's syndrome may involve first-order neurons (stroke or tumor in the hypothalamus and brainstem), second-order neurons (cervical spinal trauma, syringomyelia, cervical chain involvement by a Pancoast tumor, cervical rib, or tumor) or third-order neurons (internal carotid artery dissection, craniofacial or orbital trauma). Second-order neuron involvement may also occur during inadvertent injury from the placement of a central venous line or chest tube.

Horner's syndrome secondary to involvement of third-order neurons is often idiopathic.

Differential Diagnosis

Ptosis is seen in third-nerve palsies. Miosis may be due to eye drops (pilocarpine), iritis, an Argyll-Robertson pupil (a syphilitic pupil that accommodates but does not react), and long-standing Adie's pupil.

Pupillary inequality may be due to physiologic anisocoria.

Emergency Department Treatment and Disposition

Horner's syndrome is often caused by vascular disease, trauma, or tumor. The ED physician should attempt to elucidate associated signs and symptoms that help to localize the lesion. A patient with Horner's syndrome and cranial nerve abnormalities likely has brainstem or intracavernous pathology. Therefore an associated ipsilateral abducens palsy suggests a cavernous sinus lesion, since ocular sympathetics travel with the abducens nerve within the cavernous sinus. Wallenberg's syndrome, infarction of the lateral medulla, should be considered in a patient with numbness in the ipsilateral face and contralateral extremities. These types of patients should undergo computed tomography (CT) or magnetic resonance imaging (MRI).

In the setting of cervical spine trauma, neck immobilization and appropriate imaging studies are instituted. A patient with lung or breast malignancy, risk factors, or local or radicular shoulder pain should initially undergo a chest x-ray to evaluate for chest tumor. A Pancoast tumor is usually caused by bronchogenic carcinoma and may present, as its first sign, as a Horner's syndrome.

Neck pain in association with Horner's syndrome raises the possibility of carotid artery dissection. Third-order neuronal lesions should also be suspected in those who have had neck surgery, such as carotid endarterectomy.

Clinical Pearls

1. Patients with Horner's syndrome demonstrate a narrowed palpebral fissure secondary to a combined upper eyelid ptosis and higher than normal lower eyelid position ("reverse ptosis"). This is due to loss of sympathetic innervation to both Müller's muscle of the upper eyelid and as well as to the inferior tarsal muscle of the lower eyelid.

2. The ptosis of Horner's syndrome is moderate and never complete.

3. Carotid artery dissection should be entertained in the patient with neck pain and an ipsilateral Horner's syndrome.

4. Cluster headaches, with autonomic sympathetic system dysfunction, are capable of producing an ipsilateral Horner's syndrome.

Afferent Pupillary Defect (Marcus Gunn Pupil)

Associated Clinical Features

Pupil size, controlled centrally by the Edinger-Westphal nucleus in the midbrain, is primarily based on the afferent light stimulus transmitted via the anterior visual pathway (Fig. 2.39). These afferents synapse both ipsilaterally and contralaterally within the midbrain, and pupillomotor fibers within the oculomotor nerves exit the midbrain to supply the direct and consensual responses. Even with a unilateral light stimulus, efferents travel to both pupils and, as a result, pupil size is symmetric. Efferents and pupil size are thus dependent upon the anterior visual structures, including the retina, optic nerve, chiasm, optic tract, and midbrain pathways. A defect anywhere along this pathway modulates the strength of the afferent light stimulus. An eye with, for example, retinal or optic nerve disease generates a diminished afferent response because less light is "perceived"; pupil contraction is decreased as a result. However, when the contralateral healthy eye is stimulated with light, the abnormal pupil's consensual response is normal, since the afferent light stimulus is normal. In this situation the diseased eye is said to demonstrate an afferent pupillary defect (APD), also called a Marcus Gunn pupil.

Figure 2.39

Afferent Pupillary Defect Schematic representation of an afferent pupillary defect (APD) due to neurologic lesion in the anterior visual pathway.

A Marcus Gunn pupil is best appreciated by the swinging flashlight test, which discloses differences in afferent stimuli between the two eyes. To perform this, a flashlight is directed onto one pupil and then the other. The normal pupillary response to the flashlight is a prompt constriction. (Generally this is followed by a slight "release" dilation.) Normally the brief interval required to move the light from one eye to the other permits the pupils to begin to dilate. Thus, under normal circumstances, when the light reaches the second eye, constriction can again be observed. In the abnormal situation with a diseased second eye, however, the pupils dilate instead of constrict (Fig. 2.40). This is because this second eye perceives less light than the first, and the midbrain therefore sets pupil size to be larger.

Figure 2.40

Marcus Gunn Pupil These photographs demonstrate an afferent pupillary defect of the left pupil. When the light shines in the affected left eye, the pupils are less constricted than when the light shines in the right eye. Thus, when the light is swung from the right pupil to the left, the pupils appear to dilate. The anisocoria here is subtle. (Courtesy of Frank Birinyi, MD.)

The swinging flashlight test is an extremely useful screening technique and one of the most important assessments for evaluation of optic nerve dysfunction. Although sensitive, the swinging flashlight test is not specific, since the pathology may be anywhere in the visual pathway from the retina to the midbrain. Within the globe, limited pathology such as a cataract or occlusion of a branch retinal vein or branch retinal artery is unlikely to produce a clinically detectable APD. However a detectable APD may be seen in cases of occlusion of the central retinal vein or artery, retinal detachment, or a dense hemorrhage in the anterior chamber or vitreous. An APD in the absence of gross ocular disease indicates pathology elsewhere in the anterior visual pathway, such as a compressive lesion involving the optic chiasm or tract. Typically, however, a positive finding is indicative of optic nerve disease. A Marcus Gunn pupil is best seen in conditions involving the optic nerve, such as ischemic optic neuropathy, optic neuritis (including that seen with multiple sclerosis), retrobulbar optic neuritis, and glaucoma.

In patients with an APD, associated findings may include decreased visual acuity and decreased visual fields. Funduscopic findings may demonstrate the basis for the APD; they include occlusion of a central retinal vein or artery, optic nerve pallor, optic nerve cupping, or severe vitreal hemorrhage.

Differential Diagnosis

An Adie's pupil, more common in young women, shows a diminished or absent reaction to light. It occurs with both direct and consensual response. Acutely, the Adie's pupil is dilated; chronically, it may be constricted. An Argyll-Robertson pupil, seen in neurosyphilis, is usually bilateral and miotic, it does not respond to light stimulation, but it does accommodate.

Emergency Department Treatment and Disposition

The finding of a Marcus Gunn pupil is nonspecific. A funduscopic examination may provide the basis for the APD, and ophthalmic consultation is indicated. If the funduscopic examination is normal, a neurologic evaluation (history, physical examination, and CT scan) is important to assess for treatable conditions. In the absence of gross ocular or neurologic disease, a clinically stable patient may be discharged from the ED with ophthalmology follow-up.

Clinical Pearls

1. Afferent pupillary defects do not cause anisocoria because any change in light input results in a bilaterally symmetric output from the midbrain.

2. Dim room illumination may be helpful in performing the swinging flashlight test. The patient should focus on an object 15 ft away to avoid the pupillary constriction normally seen with accommodation.

3. The normal pupillary response to bright light is an initial constriction followed by a small amount of dilation. In performing the swinging flashlight test, it is important to assess the initial reaction. In the Marcus Gunn pupil, this initial reaction is dilation.

4. A "subjective" APD (as can be seen in mild cases of optic neuritis) is demonstrated when no objective APD is seen but the patient perceives less light in the affected eye and has mildly decreased visual acuity.

5. If an eye is damaged or paralyzed or anisocoria is present, an APD can still be assessed by observing the response of the normal pupil with light that is shined alternately in each eye. As the light shines in the abnormal eye, the normal eye dilates if the abnormal eye "perceives" less light.

Third-Nerve Palsy

Associated Clinical Features

The third cranial nerve controls all extraocular muscles (except the lateral rectus and superior oblique) as well as the levator palpebrae muscle. It also supplies parasympathetic input to the pupillary constrictor and ciliary muscles. Thus symptoms of third-nerve palsy include double vision, droopy lid, an enlarged pupil, and blurred vision at near range. If the ptosis is complete, diplopia may not be recognized. The clinical examination demonstrates a dilated and unreactive pupil, limited extraocular movements, and ptosis (Fig. 2.41). The affected pupil faces laterally (exotropia) secondary to the unopposed action of the lateral rectus.

Figure 2.41

Third-Nerve Palsy This composite shows the classic defects of a third cranial nerve palsy in all fields of gaze. The pupil is dilated. Conjugate eye movement is present in only one position, when the affected eye gazes laterally to the affected side (intact lateral rectus). When gaze is directly ahead, exotropia is seen secondary to the unopposed lateral rectus muscle of the affected side. (Courtesy of Frank Birinyi, MD.)

A third-nerve palsy can result from a lesion anywhere along its anatomic path, which begins in the brainstem nucleus, continues within the subarachnoid space, traverses the cavernous sinus, and terminates within the orbit. Associated signs and symptoms help to delineate a more precise location. An oculomotor palsy with contralateral hemiplegia suggests brainstem involvement. Infarction of the midbrain, involving the third nerve and corticospinal tracts (with contralateral hemiplegia), comprises Weber's syndrome.

In cases of isolated oculomotor palsy, the subarachnoid space is the most likely site of pathology. On leaving the brainstem, the nerve enters the subarachnoid space and travels alongside the posterior communicating artery. A common and extremely important cause for a third-nerve palsy with pupillary involvement is a posterior communicating artery aneurysm at the junction of the posterior communicating and internal carotid arteries. Because of the dorsal and medial location of the parasympathetic fibers (controlling pupillary constriction) within the oculomotor nerve bundle, these fibers are particularly susceptible to compressive lesions, and pupillary involvement often precedes ophthalmoparesis. With uncal herniation, enlarging lesions or edema in the middle fossa or temporal lobe push the medial edge of the uncus toward the midline and over the edge of the tentorium, compressing the underlying third nerve. Other causes of oculomotor dysfunction within the subarachnoid space include compressive neoplasms, inflammatory lesions, and trauma. Typically the trauma is severe enough to cause a skull fracture and loss of consciousness. An oculomotor palsy after minor trauma suggests an underlying mass lesion or aneurysm.

An oculomotor palsy secondary to pathology within the cavernous sinus may be inferred by associated involvement of the other structures within the cavernous sinus itself. These include the trochlear and abducens nerves, the first division of the trigeminal nerve, sympathetics to the eye, and the venous drainage of the eye and orbit. Causes for a third-nerve palsy within the cavernous sinus include neoplasms (pituitary, meningioma, craniopharyngioma, nasopharyngeal, metastatic), compression by carotid artery aneurysm, cavernous sinus thrombosis, and carotid-cavernous fistula. A carotid-cavernous fistula can present abruptly and dramatically as a result of reversal of blood flow in the orbital and ocular venous systems. These patients may complain of a bruit and pain. Clinical findings include pulsatile exophthalmos, elevated intraocular pressure, and chemosis. Vascular findings may be diffuse or localized. Conjunctival vessels are dilated and have a corkscrew appearance. A bruit may be audible by placing the bell of the stethoscope over the closed eyelid. Cavernous sinus thrombosis presents similarly to carotid-cavernous fistula, and the patients commonly have manifestations of sepsis. Within the anterior aspect of the cavernous sinus, the third nerve divides in two. The superior division innervates the levator palpebrae superioris and superior rectus muscles, while the inferior division innervates the medial rectus, inferior rectus, and inferior oblique muscles as well as the parasympathetics (preganglionic to the ciliary ganglion). Therefore third-nerve palsies due to cavernous sinus and orbital lesions are frequently partial, and the pupillomotor fibers may be spared.

Orbital lesions causing third-nerve palsies may be due to inflammation, trauma, neoplasms, and mucoceles. Associated clinical findings include proptosis, visual loss, and sixth-nerve involvement. As noted, an oculomotor palsy secondary to orbital pathology may be partial. In cases of trauma, the slit-lamp examination may demonstrate a tear in the iris sphincter.

An isolated third-nerve palsy is common with diabetic or hypertensive disease. The cause is felt to be microvascular ischemia. In this situation, the palsy rarely affects the pupil ("pupil sparing"). Microvascular third-nerve palsies, especially in diabetics, may be exquisitely painful.

Differential Diagnosis

Unilateral pupil dilation is also seen with minor eye trauma, eye drops (either alpha-adrenergic agents or anticholinergics such as atropine), inadvertent contamination from a scopolamine patch, and an acute Adie's pupil (a dilated and minimally reactive or nonreactive pupil, seen unilaterally and most often in young women). Myasthenia gravis, thyroid disease, temporal arteritis, and orbital inflammatory pseudotumor have similar features. Ptosis is seen in Horner's syndrome.

Emergency Department Treatment and Disposition

The evaluation of a patient with a third-nerve palsy is dependent upon the associated signs and symptoms that help to localize the pathology. In patients with involvement of the brainstem, CT or MRI is indicated. Associated fever, headache, depressed level of consciousness, neck stiffness, or other cranial nerve involvement should prompt consideration for CT scanning and subsequent spinal tap. If cavernous sinus involvement is suspected, MRI with gadolinium is preferred. For orbital pathology, CT scanning with contrast and thin coronal and axial views is recommended.

Of particular concern is the sudden onset of a third-nerve palsy accompanied by "thunderclap" headache, stiff neck, and a depressed level of consciousness. Even those with pupil sparing should be treated as neurosurgical emergencies and require immediate evaluation for an aneurysm or uncal herniation. The workup includes emergent CT or MRI. If subarachnoid hemorrhage is not found and suspicion of aneurysmal leakage remains high, a lumbar puncture should be performed. Options include CT with contrast and magnetic resonance angiography. However, the "gold standard" remains angiography, since small aneurysms can be missed, and even small aneurysms can rupture.

In the setting of head trauma, a patient with third-nerve palsy should undergo measures to reduce the intracranial pressure. These include elevation of the head of the bed, mannitol, and burr holes.

Patients under 50 years of age with isolated third-nerve palsy of any extent should undergo a full neurologic evaluation, including cerebral angiography. For patients older than 50 with vasculopathic risk factors who present with isolated pupil-sparing third-nerve palsies felt to be secondary to an ischemic neuropathy, the minimum ED evaluation should include measurement of the blood pressure and glucose. Such patients may be discharged from the ED provided that they can be observed closely for a week for evidence of pupillary involvement. Microvascular third-nerve palsies can be exquisitely painful and thus may require analgesics for 1 to 2 weeks. The majority of microvascular third-nerve palsies resolve within 3 months.

Clinical Pearls

1. A third-nerve palsy can result from pathology anywhere along its anatomic pathway, beginning with the brainstem, continuing within the subarachnoid space, traversing the cavernous sinus, and terminating within the orbit itself.

2. Patients with the abrupt onset of a "thunderclap" headache and third-nerve palsy require immediate neurosurgical evaluation for an aneurysm. (Posterior communicating artery is a common cause.)

3. In patients over 50 years of age with pupil-sparing third-nerve palsies, the etiology is usually hypertensive or diabetic vascular disease.

4. In the patient who presents with diplopia and possible third-nerve palsy, the ED physician should confirm the binocularity of the diplopia by monocular occlusion. Monocular diplopia is optical in origin.

5. A carotid-cavernous fistula most often (80%) results from trauma. It may be manifest at the time of injury or delayed for days or weeks. The trauma may be trivial in some patients.

Sixth-Nerve Palsy

Associated Clinical Features

The abducens nerve innervates the lateral rectus muscle and is the most common single-muscle palsy. Paralysis produces loss of abduction (Fig. 2.42) and horizontal diplopia. The diplopia is accentuated with gaze toward the affected side. Patients tend to turn their faces toward the affected eye to limit their diplopia. Other eye movements are normal; the lid and pupil are not affected.

Figure 2.42

Sixth-Nerve Palsy Loss of abduction of the left eye is seen in lateral gaze, demonstrating an isolated sixth-nerve palsy. (Courtesy of Frank Birinyi, MD.)

Other associated findings are dependent upon the location of the lesion causing the sixth-nerve palsy. Within the pons, involvement of adjacent structures such as the corticospinal tract results in contralateral hemiparesis. Wernicke's encephalopathy affects the abducens nucleus and manifests as ipsilateral conjugate gaze palsy—i.e., paresis of the ipsilateral lateral rectus and contralateral medial rectus. This occurs because the abducens nucleus comprises two populations of neurons. One group forms the sixth nerve. The other group sends fibers to join the contralateral medial longitudinal fasciculus, with projection to the medial rectus subnucleus.

As the nerve emerges from the pons, the abducens ascends the clivus and is vulnerable to compression by downward or forward movement of the brainstem. In fact, the abducens nerve has the longest intracranial course of any nerve; it is therefore vulnerable to "stretching," resulting in sixth-nerve palsies, unilateral or bilateral, due to elevated intracranial pressure, trauma, neurosurgical manipulation, and cervical traction. Aneurysmal compression is much less common than is seen with third-nerve palsy. Any meningeal process (infectious, inflammatory, or neoplastic) is capable of affecting this portion of the sixth nerve.

Prior to entering the cavernous sinus, the abducens nerve crosses the petrous portion of the temporal bone. Trauma with temporal bone fracture can result in a combination of sixth- and seventh-nerve palsies, including bilateral palsies. Additional clinical findings of a basilar skull fracture include hemotympanum, Battle's sign, and leakage of CSF or blood from the external ear canal.

Pathology within the cavernous sinus can affect, in addition to the abducens nerve, the internal carotid artery, the venous drainage of the eye and orbit, trochlear and oculomotor nerves, the first division of the trigeminal nerve, and the ocular sympathetics. The abducens tends to be particularly involved with vascular lesions within the cavernous sinus because of its adjacent position inferolateral to the carotid. A carotid-cavernous fistula can present abruptly and dramatically as a result of reversal of blood flow in the orbital and ocular venous systems. These patients may complain of a bruit and pain. Clinical findings include pulsatile exophthalmos, elevated intraocular pressure, and chemosis. Vascular findings may be diffuse or localized. Conjunctival vessels are dilated and have a corkscrew appearance. A bruit may be audible when the bell of the stethoscope is placed over the closed eyelid.

Within the orbit itself, isolated involvement of the sixth nerve is rare because of its short course prior to innervating the lateral rectus muscle.

The abducens nerve may be infarcted by microvascular changes secondary to diabetes, hypertension, giant cell arteritis, or arteriosclerosis. In children, a transient sixth-nerve palsy may follow a virus infection.

Differential Diagnosis

Thyroid eye disease, orbital inflammatory pseudotumor, myasthenia gravis, Duane's syndrome (congenital absence of the sixth-nerve nucleus), Parinaud's syndrome (dorsal midbrain syndrome), and medial rectus entrapment secondary to an ethmoid fracture have similar findings.

Emergency Department Treatment and Disposition

The ED evaluation is guided by the associated signs and symptoms. With involvement of the brainstem or cavernous sinus, CT or MRI is indicated. Pathology localized to the subarachnoid space should prompt consideration for CT scanning and subsequent spinal tap.

Children with antecedent viral illness and normal CT scan may be discharged provided that close follow-up is arranged. Children usually recover completely within 4 months. In the elderly, an isolated sixth-nerve palsy is likely ischemic, transient, and not indicative of underlying neurologic disease. In these cases, a glucose and an erythrocyte sedimentation rate (for evidence of giant cell arteritis) are appropriate. Although the palsy generally resolves in 3 to 4 months, these patients should be followed up carefully for the onset of additional neurologic abnormalities.

There is no treatment for the palsy itself except for patching the affected eye if diplopia is bothersome.

Clinical Pearls

1. Isolated sixth-nerve palsy is commonly due to microvascular disease, not an aneurysm.

2. An isolated lateral rectus palsy should not be considered nuclear in origin.

3. A deficit involving a sixth-nerve palsy with an ipsilateral Horner's syndrome is usually localized to the cavernous sinus, since sympathetic fibers, as they traverse from the internal carotid artery to the oculomotor nerve, may briefly accompany the abducens nerve.

4. Basilar skull fractures of the temporal bone are capable of producing a traumatic sixth-nerve palsy, since the nerve passes from the posterior fossa to the cavernous sinus via the petrous ridge.

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