Neonatal Conjunctivitis

Etiology

The age of the baby is an important clue towards the etiology of neonatal conjunctivitis; however, bacterial infections can occur anytime. The following is a summary of occurrences and causes.[6][7][8][5][8]

• First 24 hrs of life: Chemical causes like silver nitrate drops or from prophylactic medicines like erythromycin drops and gentamicin drops.
• 24 to 48 hrs of life: Bacterial causes are most likely (Neisseria gonorrhoeae is the most common cause, Staphylococcus aureus).
• 5 to 14 days of life: Chlamydia trachomatis
• 6 to 14 days of life: Herpes keratoconjunctivitis
• 5 to 18 days: Pseudomonas aeruginosa 

Epidemiology

The incidence of infectious neonatal conjunctivitis ranges from 1% to 2%.

The epidemiology of neonatal conjunctivitis changed when silver nitrate solution was introduced in the 1800s to prevent gonococcal ophthalmia. Chlamydia is the most common infectious agent that causes ophthalmia neonatorum in the United States, where 2% to 40% of neonatal conjunctivitis cases are caused by Chlamydia.

In contrast, the incidence of gonococcal ophthalmia neonatorum has been reduced dramatically and causes less than 1% of cases of neonatal conjunctivitis.[5]

Pathophysiology

Neonates are at higher risk of conjunctivitis due to many predisposing factors, such as:

• Decreased tear production
• Lack of IgA in tears
• Decreased immune function
• Absence of lymphoid tissue in conjunctiva
• Decreased lysozyme activity

Risk factors include premature rupture of membranes, prolonged delivery, prematurity, poor prenatal care, maternal STI, mechanical ventilation, poor hygiene conditions, history of midwife assistance, and HIV-infected mothers.

Neonates at higher risk of congenital lacrimal duct obstruction include those with Down syndrome, Goldenhar Syndrome, clefting syndromes, midline facial anomalies, hemifacial microsomia, and craniosynostosis.[5]

Histopathology

Conjunctival studies will reveal the following for each of the following organisms:

• Chemical conjunctivitis: Negative gram stain with few polymorphonuclear cells.

• Gonococcal conjunctivitis: Gram-negative, kidney-bean shaped, intracellular diplococci on culture with specific media.

• Chlamydial conjunctivitis: Basophilic intracytoplasmic inclusions in epithelial cells on gram stain. 

• Herpetic conjunctivitis: Multinucleated giant cells on gram stain.

History and Physical

A purulent discharge, edema, and erythema of the lids and hyperemia of the conjunctiva are suggestive of conjunctivitis. Discharge can be purulent in bacterial conjunctivitis and watery in viral etiology. Gonorrhea has a profuse, purulent discharge, Pseudomonas has a greenish discharge, and chlamydia can be watery, followed by purulent and bloody discharge.

Laterality, unilateral conjunctivitis is most often seen with S. aureus, P. aeruginosa, Herpes simplex, and adenovirus. Bilateral conjunctivitis is seen with infection caused by N. gonorrhea or by use of ocular prophylaxis. Chlamydia usually develops in one eye but affects the other after 2 to 7 days.

The physical exam should include evaluation for red reflex, ulcerations (corneal and conjunctival), and adenopathy. One should also rule out signs of respiratory and systemic infection.

A history of sexually transmitted infection in the mother increases the risk of chlamydia and gonorrhea. Neonatal conjunctivitis is frequently diagnosed in neonates born to HIV-infected mothers.[5]

Evaluation

Differential diagnosis includes eye discharge that can be conjunctivitis or congenital lacrimal duct obstruction. Other diagnoses may be ocular foreign body, orbital or preseptal cellulitis, entropion, trichiasis, eye trauma (corneal abrasion following delivery), dacryocystitis, keratitis, subconjunctival hemorrhage (breakage of vessels during delivery), congenital anomalies of nasolacrimal system, corneal epithelial disease, neonatal abstinence, and congenital glaucoma.

Physical exam should evaluate for periorbital edema and adenopathy. Examine both eyes/eyelids for swelling and edema, and check conjunctiva for injection (congestion of blood vessels) and chemosis (conjunctival swelling). Check for ulcerations and the presence of red reflex. A purulent discharge, edema, and erythema of the lids, as well as injection of the conjunctiva, are suggestive of bacterial conjunctivitis.

Lab studies include Gram stain and culture to check WBC and bacteria, as well as sensitivity and culture of the bacteria isolated (chocolate agar and Thayer-Martin media for gonorrhea and blood agar for another medium). A Giemsa stain should be done for chlamydial suspicion. However, chlamydia is now more commonly diagnosed via nucleic acid amplification tests (NAATs), which are less expensive and require less labor than traditional viral cultures. Of note, newborns with suspected C. trachomatis infection should have samples drawn from both the conjunctivae and oropharynx. Because C. trachomatis is an obligate intracellular organism, swabs should not only be taken from eye discharge but should also include conjunctival epithelial cells if possible.

No imaging and other studies are usually needed, but a fluorescein dye disappearance test can be done to rule out nasolacrimal duct obstruction.[5]

Treatment / Management

General factors important in management include the following:

• Avoid cross contamination by frequent hand washing and wearing gloves
• Irrigate the eye with sterile isotonic saline
• Systemic treatment is required for staphylococcal, gonococcal, Chlamydia, Pseudomonas, and herpetic conjunctivitis
• Avoid eye patching
• Consider pediatric infectious disease and/or pediatric ophthalmology consult
• Chemical conjunctivitis usually resolves within 24 to 72 hours and may be helped with lubrication and artificial tears

Gonococcal conjunctivitis: a medical emergency. Because of PCB resistance, third-generation cephalosporins are the first line antibiotics. It can happen even with appropriate prophylaxis infants delivered to mothers with positive maternal gonococcal infection.[9][10][11][12][13][5][13](B3)

• Ceftriaxone 25-50mg/kg intravenous or intramuscular x 1 dose
• The alternative is cefotaxime single dose of 100 mg/kg
• Isolate the infant during the first 24 hours of parenteral antibiotic therapy
• Test for concomitant HIV and syphilis
• Evaluate for disseminated disease (arthritis, meningitis, sepsis, anorectal infection)
• Consider treating for chlamydia due to the high rate of concomitant infection
• Keep a low threshold to evaluate for systemic infection (sepsis, meningitis)
• Ophthalmology consult since gonococcal conjunctivitis can lead to perforation and blindness
• Irrigate the eyes with normal saline at frequent (1 to 2 hour) intervals
• Topical antibiotics are not necessary

Chlamydial conjunctivitis: Recommended prophylaxis does not prevent chlamydial conjunctivitis, and topical treatment is ineffective and unnecessary but may be used as an adjunct to oral therapy. Topical therapy for chlamydial conjunctivitis is generally not effective and has a high failure rate because C. trachomatis is known to colonize the nasopharynx and can thus spread into the lungs if not adequately eradicated.

Erythromycin x 14 days or azithromycin 20 mg/kg/day x 3 days is the recommended treatment. However, the American Academy of Pediatrics still recommends erythromycin because other treatments are not well studied.

A second course is usually required since 1 in 5 cases recur after antibiotic therapy. Pyloric stenosis has been seen in infants less than six weeks old treated with erythromycin.

For infants born to mothers with chlamydia exposure, there is no prophylaxis recommended, but it is important to educate the family to monitor for infection, including pneumonia.

Herpetic conjunctivitis: Administer topical vidarabine or trifluridine five times a day for ten days and evaluate and treat for systemic herpes; an ophthalmology consult is indicated. Systemic treatment with acyclovir is also indicated for SEM (skin, eye, and mucosa) and central nervous system infection. Ophthalmologic evaluation is recommended as retinopathy, cataracts, and chorioretinitis can develop.

Isolation: Isolation of a patient is recommended for Pseudomonas, herpes, and gonococcal conjunctivitis.

Lacrimal Duct Obstruction: Most clear spontaneously without treatment. If the problem does not resolve and symptoms persist (usually after 6 to 7 months), the infant should be evaluated by an ophthalmologist.

Differential Diagnosis

• Bacterial keratitis

• Dacryocystitis

• Fungal keratitis

• Herpes simplex virus keratitis

• Nasolacrimal duct obstruction and epiphora

• Orbital cellulitis

• Preseptal cellulitis

• Primary congenital glaucoma

• Secondary congenital glaucoma