Conjunctivitis of the newborn

Prophylaxis

Credé first described the use of ocular prophylaxis in newborns. The widespread use of prophylaxis resulted in a great reduction in conjunctivitis-related blindness, but unfortunately ophthalmia neonatorum-related corneal scarring remains a leading cause of childhood blindness in developing countries.

Types of prophylaxis include silver nitrate 1%, povidone-iodine 2.5%, erythromycin ointment 0.5%, and tetracycline ointment 1%. These agents are meant to be administered to the inferior conjunctival fornix of both eyes within 1 hour of an infant’s delivery. Silver nitrate is the agent most likely to cause a chemical conjunctivitis. Silver nitrate and tetracycline have demonstrated equal efficacy (83%−93%) in the prevention of gonococcal ophthalmia neonatorum. In a randomized controlled trial of 3117 Kenyan newborns, povidone-iodine 2.5% was more effective than erythromycin or silver nitrate for prophylaxis of infectious conjunctivitis (13.1% vs. 17.5% vs. 15.2%). In a smaller trial involving 410 Israeli newborns, the rate of infectious conjunctivitis appeared higher with povidone-iodine (10.4%) than with tetracycline (5.4%), but the difference failed to reach statistical significance ( P = 0.052); as expected, povidone-iodine was more likely to cause a chemical conjunctivitis than tetracycline (5% vs. 0%). When using povidone-iodine, care should be taken to use a prep solution and not a scrub formulation, which causes significant chemical conjunctivitis and even corneal decompensation.

In the United States, erythromycin 0.5% is used as the topical prophylactic agent. During an erythromycin shortage in 2009, the Centers for Disease Control recommended topical azithromycin 1% solution, or, if unavailable, topical gentamicin 0.3% or tobramycin 0.3% ointments. However, azithromycin is approximately 10 times more costly than povidone-iodine prepared by a hospital pharmacy, and topical gentamicin can cause periocular ulcerative dermatitis and should be avoided altogether.

Term colostrum shows insufficient antibacterial activity to be used as prophylaxis for neonatal conjunctivitis, and term milk shows no inhibitory activity.

Chemical Conjunctivitis

Chemical conjunctivitis develops within 1−2 days after the administration of a topical agent and is bilateral. It is most common following prophylaxis with silver nitrate. Gram stain shows leukocytes but no organisms. Conservative management typically results in gradual resolution of symptoms within a couple of days, though sometimes a mild ophthalmic topical steroid can be useful in hastening resolution.

Chlamydial Conjunctivitis

The prevalence of Chlamydia trachomatis among pregnant women ranges from 2% to 20%; the higher rates are among younger women and those without prenatal care. The likelihood that an infant born to a mother with untreated C. trachomatis infection develops symptomatic conjunctivitis ranges from 20% to 50%.

Chlamydial conjunctivitis ( Fig. 12.1A ) typically develops 5−14 days after delivery, but can present earlier. Though more common among infants born vaginally, it can follow cesarean section delivery. The conjunctivitis can be unilateral or bilateral, with mucopurulent discharge and possible pseudomembrane (and rarely true membrane) formation. Untreated, the conjunctivitis resolves after weeks to months, but can cause conjunctival and corneal scarring, which can be blinding. Furthermore, if left untreated, it is contagious, posing a public health threat to others.

Classically, the diagnosis is made by isolating Chlamydia via culture obtained by scraping the palpebral conjunctiva for epithelial cells. Intracellular inclusions can be demonstrated on Giemsa stain. Recently, polymerase chain reaction (PCR) detection was found to have higher sensitivity (100%) and similarly high specificity (95%) compared with culture and Giemsa stain, and may be superior in mild disease.

Chlamydial conjunctivitis is associated with systemic disease, including otitis media, nasal congestion, and pneumonitis occurring later, at 4–12 weeks of life. Chlamydial conjunctivitis is treated with oral erythromycin (50 mg/kg divided into 4 daily doses) for 14 days. Asymptomatic infants born to mothers with untreated C. trachomatis infection are not treated prophylactically, in part because erythromycin use in the first two weeks of postnatal life is associated with increased risk of infantile hypertrophic pyloric stenosis. For infants with conjunctivitis but no sign of pneumonia, systemic erythromycin can be delayed while awaiting confirmatory diagnostic tests for Chlamydia , but the infant should be monitored closely for systemic signs. Oral azithromycin (20 mg/kg daily for 3 days) is an alternative, though experience with its use in neonates is limited. The mother and her sexual partners should be treated with a single dose of oral azithromycin (1 g) and be evaluated for other sexually transmitted diseases. Some areas with a high incidence of trachoma are instituting annual or biannual mass prophylaxis with oral azithromycin to reduce the incidence of C. trachomatis , with moderate success.