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Ophthalmia Neonatorum
Key Concepts
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Ophthalmia neonatorum is conjunctivitis in the first month of life.
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Chemical etiologies present in the first 24–48 hours after birth.
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Gonococcal etiologies present in the first 2–5 days after birth.
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Chlamydial infections are the most common, presenting 5–14 days after birth.
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Early diagnosis by clinical suspicion and culture is imperative.
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Early treatment is imperative to prevent local and systemic disease, which can be blinding and severe.
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Prophylaxis remains critical in reducing disease.
Ophthalmia neonatorum, or neonatal conjunctivitis, is defined as any inflammation of the conjunctiva during the first month of life. It is characterized by injection and swelling of the eyelids and conjunctiva, coupled with purulent discharge in which one or more polymorphonuclear cells are seen per high-power field on a Gram-stained conjunctival smear. Neonatal conjunctivitis manifests as a diffuse, often hyperacute conjunctivitis with a papillary reaction. A follicular response is not seen prior to 6–8 weeks of life and is therefore not a helpful finding in establishing a differential diagnosis. It can result from toxic chemical exposure to silver nitrate prophylaxis or from infectious etiology (bacterial, chlamydial, viral, or fungus). The severity of the inflammatory response depends on the inciting agent, and the sequelae can range from self-limited hyperemia and chemosis to corneal perforation, symblepharon formation, and adnexal scarring and blindness. The reported incidence ranges from 1.6% to 2% of newborns, depending on the socioeconomic character of the area. The epidemiology of neonatal conjunctivitis improved when silver nitrate solution was introduced in the 1800s to prevent gonococcal ophthalmia.
Pathogenesis and Assessment of Risk
Understanding the incubation times of the different etiologic agents can be useful clinically; however, the onset of neonatal conjunctivitis postpartum can be affected by many other factors and should only be used as a guideline ( Table 40.1 ). All infants delivered vaginally are exposed to many different bacteria. Isenberg and colleagues cultured the conjunctiva of 100 eyes of newborns within 15 minutes of delivery. (Bacteria were isolated from 75% of the 100 eyes that were cultured.) Microaerophilic bacteria including Lactobacillus species and diphtheroids accounted for 62% of all bacteria isolated, whereas true anaerobes including Bifidobacterium species, Propionibacterium acnes , and Bacteroides species accounted for 28%. However, these organisms rarely cause neonatal conjunctivitis. Aerobic bacteria accounted for only 10% of all bacteria isolated. Staphylococcus epidermidis was the most common aerobic organism followed by Corynebacterium , Streptococcus species, and Escherichia coli . The conjunctival bacteria of infants born by vaginal delivery reflect the bacterial flora of the vagina.
TABLE 40.1
Time of Onset Can Aid in Diagnosis
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The risk of developing neonatal conjunctivitis can be dependent on several factors ( Table 40.2 ). In cases of premature rupture of membranes or during a difficult delivery, the infant may have prolonged exposure to infectious agents. Premature rupture of membranes allows retrograde spread of organisms to the conjunctiva and cornea. Prolonged intrauterine exposure to infectious organisms may be largely responsible for the errors in relating the time of onset of neonatal conjunctivitis to the etiologic agent. Any trauma to the ocular tissues during delivery may further facilitate invasion by infectious organisms. Epithelial trauma may result from abrasions, exposure, or secondary to chemical prophylaxis, particularly with silver nitrate. Neisseria gonorrhoeae is an important exception to the rule that epithelial trauma predisposes to infection, because this organism is capable of penetrating intact epithelium.
TABLE 40.2
Assessment of Risk of Bacterial Neonatal Conjunctivitis
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Concomitant infection of C. trachomatis and N. gonorrhoeae must be considered. |
HIV , Human immunodeficiency virus; STI , sexually transmitted infection.
The neonate’s immune system is immature, which increases the susceptibility to infection. Inadequate antibody synthesis is largely compensated by the passive transfer of maternal IgG. However, local secretory IgA is lacking unless the infant ingests breast milk. In most premature infants and in 20% of full-term infants, the tear secretory rate is abnormally low. Lysozyme, which catalyzes the breakdown of bacterial cell membranes, has a higher concentration in tears than in serum. However, the concentration of lysozyme in tears is decreased in premature infants compared to full-term infants and adults.
After birth, a caregiver who has a “cold sore” or who harbors bacteria in the nasopharynx can inadvertently infect a neonate. Prolonged neonatal intensive care increases the potential of nosocomial infection.
The Role of Sexually Transmitted Diseases
The increasing prevalence of sexually transmitted disease accounts for the finding that Chlamydia trachomatis is now the most common cause of infectious neonatal conjunctivitis in industrialized countries. In the United States, over 1.4 million new infections were reported in 2013. Whereas chlamydial infections are common in higher socioeconomic groups, gonorrhea is seldom encountered. When students were screened at private colleges, chlamydial infection exceeded gonococcal infection by a factor of 5- to 10-fold in symptomatic men or in asymptomatic women having routine pelvic examinations. In contrast, in urban venereal disease clinics, chlamydial and gonococcal infections occur at the same rate. The most important factor for C. trachomatis infection is age. Younger women have the highest infection rates. In the United States, it is estimated that 5% of pregnant women have cervical chlamydial infection, placing their infants at risk. Approximately 60% of infants exposed to C. trachomatis during birth contract the infection. The incidence of neonatal conjunctivitis caused by C. trachomatis is between 5 and 60 per 1000 live births in the United States and as high as 80 per 1000 live births in Kenya.
In the United States, 333,004 gonococcal infections were reported in 2013, with similar incidence reported over the prior 10 years. , The incidence of gonococcal neonatal conjunctivitis is 0.3 per 1000 live births in the United States, whereas in Kenya the incidence is 40 per 1000 live births. More than 50% of the infants with neonatal conjunctivitis in Kenya were found to be co-infected with both N. gonorrhoeae and C. trachomatis . A study conducted in Kenya suggested that 42% of neonates exposed to N. gonorrhoeae during delivery developed gonococcal conjunctivitis.
Causes of Neonatal Conjunctivitis
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