Disorders of the Conjunctiva

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Chapter 618 Disorders of the Conjunctiva

Scott E. Olitsky, Denise Hug, Laura S. Plummer, Merrill Stass-Isern

Conjunctivitis

The conjunctiva reacts to a wide range of bacterial and viral agents, allergens, irritants, toxins, and systemic diseases. Conjunctivitis is common in childhood and may be infectious or noninfectious. The differential diagnosis of a red-appearing eye includes conjunctival as well as other ocular sites (Table 618-1).

Table 618-1 THE RED EYE

Ophthalmia Neonatorum

This form of conjunctivitis, occurring in infants younger than 4 wk of age, is the most common eye disease of newborns. Its many different causal agents vary greatly in their virulence and outcome. Silver nitrate instillation may result in a mild self-limited chemical conjunctivitis, whereas Neisseria gonorrhoeae and Pseudomonas are capable of causing corneal perforation, blindness, and death. The risk of conjunctivitis in newborns depends on frequencies of maternal infections, prophylactic measures, circumstances during labor and delivery, and postdelivery exposure to microorganisms.

Epidemiology

Conjunctivitis during the neonatal period is usually acquired during vaginal delivery and reflects the sexually transmitted infections prevalent in the community. In 1880, 10% of European children developed gonococcal conjunctivitis at birth. Ophthalmia neonatorum was the leading cause of blindness during that period. The epidemiology of this condition changed dramatically in 1881, when Crede reported that 2% silver nitrate solution instilled in the eyes of newborns reduced the incidence of gonococcal ophthalmia from 10% to 0.3%.

During the 20th century, the incidence of gonococcal ophthalmia neonatorum decreased in industrialized countries secondary to widespread use of silver nitrate prophylaxis and prenatal screening and treatment of maternal gonorrhea. Gonococcal ophthalmia neonatorum has an incidence of 0.3/1,000 live births in the USA. In comparison, Chlamydia trachomatis is the most common organism causing ophthalmia neonatorum in the USA, with an incidence of 8.2/1,000 births.

Clinical Manifestations

The clinical manifestations of the various forms of ophthalmia neonatorum are not specific enough to allow an accurate diagnosis. Although the timing and character of the signs are somewhat typical for each cause of this condition, there is considerable overlap and physicians should not rely solely on clinical findings. Regardless of its cause, ophthalmia neonatorum is characterized by redness and chemosis (swelling) of the conjunctiva, edema of the eyelids, and discharge, which may be purulent.

Neonatal conjunctivitis is a potentially blinding condition. The infection may also have associated systemic manifestations that require treatment. Therefore, any newborn infant who develops signs of conjunctivitis needs a prompt and comprehensive systemic and ocular evaluation to determine the agent causing the infection and the appropriate treatment.

The onset of inflammation caused by silver nitrate drops usually occurs within 6-12 hr after birth, with clearing by 24-48 hr. The usual incubation period for conjunctivitis due to N. gonorrhoeae is 2-5 days, and for that due to C. trachomatis, it is 5-14 days. Gonococcal infection may be present at birth or be delayed beyond 5 days of life owing to partial suppression by ocular prophylaxis. Gonococcal conjunctivitis may also begin in infancy after inoculation by the contaminated fingers of adults. The time of onset of disease with other bacteria is highly variable.

Gonococcal conjunctivitis begins with mild inflammation and a serosanguineous discharge. Within 24 hr, the discharge becomes thick and purulent, and tense edema of the eyelids with marked chemosis occurs. If proper treatment is delayed, the infection may spread to involve the deeper layers of the conjunctivae and the cornea. Complications include corneal ulceration and perforation, iridocyclitis, anterior synechiae, and rarely panophthalmitis. Conjunctivitis caused by C. trachomatis (inclusion blennorrhea) may vary from mild inflammation to severe swelling of the eyelids with copious purulent discharge. The process involves mainly the tarsal conjunctivae; the corneas are rarely affected. Conjunctivitis due to Staphylococcus aureus or other organisms is similar to that produced by C. trachomatis. Conjunctivitis due to Pseudomonas aeruginosa is uncommon, acquired in the nursery, and a potentially serious process. It is characterized by the appearance on days 5-18 of edema, erythema of the lids, purulent discharge, pannus formation, endophthalmitis, sepsis, shock, and death.

Diagnosis

Conjunctivitis appearing after 48 hr should be evaluated for a possibly infectious cause. Gram stain of the purulent discharge should be performed and the material cultured. If a viral cause is suspected, a swab should be submitted in tissue culture media for virus isolation. In chlamydial conjunctivitis, the diagnosis is made by examining Giemsa-stained epithelial cells scraped from the tarsal conjunctivae for the characteristic intracytoplasmic inclusions, by isolating the organisms from a conjunctival swab using special tissue culture techniques, by immunofluorescent staining of conjunctival scrapings for chlamydial inclusions, or by tests for chlamydial antigen or DNA. The differential diagnosis of ophthalmia neonatorum includes dacryocystitis caused by congenital nasolacrimal duct obstruction with lacrimal sac distention (dacryocystocele).

Treatment

Treatment of infants in whom gonococcal ophthalmia is suspected and the Gram stain shows the characteristic intracellular gram-negative diplococci should be initiated immediately with ceftriaxone, 50 mg/kg/24 hr for 1 dose, not to exceed 125 mg. The eye should also be irrigated initially with saline every 10-30 min, gradually increasing to 2-hr intervals until the purulent discharge has cleared. An alternative regimen includes cefotaxime (100 mg/kg/24 hr given IV or IM every 12 hr for 7 days or 100 mg/kg as a single dose). Treatment is extended if sepsis or other extraocular sites are involved (meningitis, arthritis). Neonatal conjunctivitis secondary to Chlamydia is treated with oral erythromycin (50 mg/kg/24 hr in 4 divided doses) for 2 wk. This cures conjunctivitis and may prevent subsequent chlamydial pneumonia. Pseudomonas neonatal conjunctivitis is treated with systemic antibiotics, including an aminoglycoside, plus local saline irrigation and gentamicin ophthalmic ointment. Staphylococcal conjunctivitis is treated with parenteral methicillin and local saline irrigation.

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