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Conjunctivitis in the Neonatal Period (Ophthalmia neonatorum)
Ophthalmia neonatorum is defined as conjunctivitis occurring within the first month of life. It is the most common eye disease of neonates, with an incidence ranging 1.6%–12%. Incidence is directly related to the prevalence of sexually transmitted infections (STIs) in adults. One hundred years ago, Neisseria gonorrhoeae was the most common pathogen and a major cause of blindness among children. With the advent of Credé prophylaxis (instillation of silver nitrate at time of birth) and changing trends in STIs, Chlamydia trachomatis has become the most common sexually transmitted pathogen. In general, offspring of women who receive prenatal care have a lower incidence of infectious conjunctivitis. In the absence of maternal STIs, neonatal conjunctivitis is acquired postnatally, and bacteria are the most common cause. Etiologic agents are Staphylococcus aureus , Streptococcus pneumoniae , Haemophilus spp., and viridans streptococci ( Fig. 79.1 ). Viruses, with the exception of herpes simplex virus (HSV), are less-common pathogens in this age group.
Unilateral conjunctivitis in newborn 12 hours after vaginal delivery.
Hospital-associated infection can occur in neonatal intensive care units due to S. aureus, gram-negative bacilli (especially Pseudomonas aeruginosa ), and adenovirus. Significant predictors of conjunctivitis include low birth weight, use of ventilator or nasal cannula, and continuous positive airway pressue. Ophthalmologic examination has been associated with nosocomial bacterial conjunctivitis, most notably adenovirus conjunctivitis (sometimes with dissemination and fatal outcome).
Pathogenesis
Microbial pathogens can be transmitted to the eye by a variety of routes. Premature rupture of placental membranes allows the retrograde spread of organisms to the fetal conjunctiva and cornea. Hematogenous spread can occur transplacentally as well. During vaginal delivery, the neonate’s eyes can become infected by contact with infected maternal genital secretions. After birth, caregivers can transmit pathogens to the neonate’s eyes through direct contact or aerosolization.
In addition to the immaturity of the immune system, the neonate has local risk factors for ocular infections. The secretory rate of tears under basal conditions in premature infants is about 20% of that in full-term infants, and the blink frequency is decreased. The concentration of lysozyme—the enzyme in tears that catalyzes the breakdown of the bacterial cell wall—also is diminished in premature infants compared with full-term infants and adults. A final reason for increased susceptibility of the neonatal eye is a lack of secretory immunoglobulin A (IgA) in the tears of neonates.
Etiologic Agents
Differentiating features of etiologic agents of neonatal conjunctivitis are shown in Table 79.1 , and treatment is shown in Table 79.2 .
TABLE 79.1
Differentiating Features of Neonatal Conjunctivitis
| Cause | Time of Onset | Quality of Discharge | Percentage of Cases |
|---|---|---|---|
| Chemical | 24 hours | Serous | Now rare in US |
| Neisseria gonorrhoeae | 2–7 days | Mucopurulent | 1% in developed countries |
| Chlamydia trachomatis | 5–14 days | Mucopurulent | 2%–40% |
| Herpes simplex virus | 6–14 days | Serous | <1% |
TABLE 79.2
Treatment of Neonatal Conjunctivitis
| Cause of Conjunctivitis | Treatment | Additional Management/Treatment |
|---|---|---|
| Neisseria gonorrheae | Ceftriaxone 25–50 mg/kg IV or IM single dose not to exceed 125 mg IM Plus Topical moxifloxacin eyedrops every 4 hours for 3 days |
Perform saline rinse hourly for 12 hours. Monitor bilirubin |
| Chlamydia trachomatis | Erythromycin base or ethylsuccinate orally (50 mg/kg/day in 4 divided doses daily) for 14 days Or Azithromycin orally (20 mg/kg as a single daily dose) for 3 days |
Test and treat mother and all sexual partners 10% of patients may need re-treatment |
| Herpes simplex virus | Acyclovir IV (60 mg/kg/day in 3 divided doses) for 14 days for isolated mucocutaneous infection | Investigate for disseminated and CNS infection |
| Polymicrobial | Topical moxifloxacin eyedrops every 4 hours for 3 days Or Polymyxin/trimethoprim eyedrops every 4 hours for 3 days |
Chlamydia trachomatis
Epidemiology
C. trachomatis is the most common cause of infective neonatal conjunctivitis. Frequency of conjunctivitis reflects the prevalence of maternal genital infections, ranging 18%–23%. The likelihood of transmission from untreated infected mothers to infants ranges 18%–61%.
Clinical Manifestations
Chlamydial conjunctivitis is usually clinically evident within 5–14 days of birth, although it can appear as early as 3 days, especially after premature rupture of membranes, or as late as 60 days. Typical findings are eyelid swelling, erythema, and unilateral or bilateral mucopurulent conjunctivitis; the cornea usually is not involved. On occasion, pseudomembranes and (rarely) true membranes develop. The expected lymphoid follicular response of the conjunctiva does not appear unless the infection persists beyond 6 weeks of age. In treated cases, healing usually occurs without sequelae. Infection in untreated or inadequately treated cases can persist for 2–12 months, and some cases remain clinically apparent for years. Persistent infection can lead to conjunctival scar formation and corneal micropannus.
The major nonocular complication of chlamydial conjunctivitis is pneumonia. Pneumonia develops in 11%–20% of infected infants and typically manifests at 1–3 months of age. Infants usually are afebrile but have nasal congestion, prolonged cough, tachypnea, and rales. Hyperinflation with interstitial or alveolar infiltrates is evident radiographically. Total serum IgG and IgM antibody values are elevated, and eosinophilia sometimes occurs. Antibodies to C. trachomatis are detectable in tears and serum. Although infection usually is self-limited, systemic treatment is recommended because it shortens the duration of ocular and respiratory tract illness and because treatment of ocular infection prevents pneumonia.
Diagnosis
In the past, C. trachomatis conjunctivitis was diagnosed by Giemsa staining of conjunctival scrapings showing blue-stained intracytoplasmic inclusions within epithelial cells. The sensitivity of Giemsa staining ranges widely, 22%–95%, reflecting varied technical and examiner skill. Staining has been replaced by use of nucleic acid amplification test (NAAT) performed on conjunctival swabs. These tests are available widely and provide rapid results with high sensitivity. Organism detection by direct fluorescence has lower sensitivity and is difficult to standardize but is less costly.
Treatment
Systemic therapy for conjunctivitis due to C. trachomatis is recommended in all cases to treat conjunctivitis and to prevent pneumonia. Erythromycin estolate or ethylsuccinate, 50 mg/kg/day in 4 divided doses for 14 days, is curative in about 80% of cases. A short course of azithromycin (20 mg/kg), given as a single dose or daily for 3 days, also may be effective and may be less associated with idiopathic hypertrophic pyloric stenosis. Topical corticosteroid therapy is contraindicated because it can prolong the infection and possibly lead to conjunctival scarring.
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