Gonococcal Conjunctivitis

Etiology

GC is due to ophthalmic infection with Neisseria gonorrhoeae, a gram-negative diplococcus. In neonates, the transmission of N gonorrhoeae and subsequent development of GC often occurs during delivery and exposure to infectious vaginal secretions. This occurs because the mucosa of the cervix and urethra of infected mothers can act as bacterial reservoirs. Even with delivery via cesarean section, vertical transmission of N gonorrhoeae is still possible. Approximately 10% of neonates exposed to gonorrheal exudates during delivery may go on to develop GC, even with appropriate prophylaxis. In populations other than neonates, transmission can occur via direct sexual contact with infective secretions or indirectly, for example via manual or fomite transmission, though this is thought to be less likely since N gonorrhea does not typically survive more than a few minutes outside the human body. There has also been evidence that suggests that GC could potentially be due to different strains of gonococci that are not associated with sexually transmitted infections.[5][6][7]

Epidemiology

Worldwide, the incidence of gonococcal infection in newborns is less than 1%. Developed countries tend to have lower incidences due to the availability of screening and treatment options. Rates in developing countries are likely to be significantly higher considering the prevalence of gonococcal infection in pregnancy nears 5% in some parts of Africa. In the United States, the incidence of conjunctivitis ranges from 1% to 2% in neonates with the incidence of neonatal GC estimated to be less than 1%. As mentioned previously, in neonates that have appropriate chemoprophylaxis, up to 10% may still develop GC compared to up to 48% of neonates that do not. In the non-neonatal populations, GC is rare. In the United States, sexually transmitted infection surveillance estimates nearly 146 cases of gonorrhea per 100,000 population, but specific estimates of GC have not been well-studied. However, results from a recent study in Ireland estimated that the prevalence of GC was 0.19 cases per 1000 patients evaluated for eye emergencies with the majority presenting in young adult males.

Pathophysiology

The main concept is that N gonorrhoeae can attach to and penetrate the epithelial cells of mucosal surfaces such as the conjunctiva. Once inside, the bacteria can proliferate and induce pro-inflammatory mechanisms. However, there is evidence that N gonorrhoeae have developed methods for evading and even modulating immune responses, which can potentially lead to disseminated infection, for example, bacteremia or meningitis.

History and Physical

Neonatal GC is often acquired during delivery; thus, there usually is a history of suspected or confirmed maternal gonorrheal infection. Bacterial conjunctivitis can occur at any time, but GC is considered in symptomatic neonates after the first day of life, specifically, days 2 to 5, since chemical conjunctivitis (secondary to silver nitrate, antibiotic drops) is often the cause in the first 24 hours. A physical exam may reveal the following:

• Conjunctival injection, chemosis
• Edema of the eyelids
• Mucopurulent discharge
• Tenderness of the globe
• Lymphadenopathy, preauricular

In the non-neonatal population, GC may present with similar symptoms and should at least be considered in sexually active individuals who present with conjunctivitis with or without genital symptoms. Regardless, a detailed sexual history of the mother and non-neonatal cases of conjunctivitis should be obtained to refine the differential diagnoses for conjunctivitis.

Evaluation

For patients presenting with conjunctivitis concerning possible GC, further diagnostics are suggested to confirm the diagnosis. A sampling of conjunctival scrapings or exudative fluid can be sent for the following:

• Gram stains are helpful, as they may reveal gram-negative intracellular diplococci.
• Culture on Thayer-Martin media or chocolate agar for N gonorrhoeae and blood agar for non-gonococcal species is recommended.
• Polymerase chain reaction can also be used to test for N gonorrhoeae as well as Chlamydia trachomatis.
• Screening for other sexually transmitted infections such as the human immunodeficiency virus is also recommended in mothers and non-neonatal cases due to co-infections that can occur with sexually transmitted infections is essential.
• Consideration should also be given to taking genital and throat swabs in patients with risk factors.

Treatment / Management

Due to the progression risk of disseminated gonococcal infection, neonates with GC should be approached as emergent cases that warrant admission and observation. The most effective treatment of GC is prevention, and it is recommended that females be screened for gonorrhea and other sexually transmitted infections if considered high-risk (prior history of sexually transmitted infection, commercial sex workers) and should be appropriately treated. Nevertheless, cases of neonatal GC can occur even with appropriate prophylactic measures. Below is a summary of the recommended therapies.[8][9][10][11](B3)

Neonatal Prophylaxis

• Erythromycin (0.5%) ophthalmic ointment
• Tetracycline (1%) ophthalmic ointment

Symptomatic or High-Risk Neonate 

• Ceftriaxone (25 mg/k to 50 mg/kg, max 125 mg intravenously (IV) or  intramuscularly (IM), single dose, or
• Cefotaxime (100 mg/kg IV/IM), single dose, which may be preferred if available due to the risk of increasing bilirubin levels associated with ceftriaxone
• Hourly saline lavage

Non-Neonate With Symptoms 

• Ceftriaxone (1 gm IM), single dose, and
• Azithromycin (1 gm oral), single dose, which is added on due to the frequent co-infection with Chlamydia trachomatis
• Saline lavage can be considered but is not a necessity

Differential Diagnosis

Differential diagnosis to consider and rule out regarding gonococcal conjunctivitis include the following:

• Adult blepharitis
• Allergic conjunctivitis
• Acute angle-closure glaucoma 
• Chemical burns
• Contact lens conjunctivitis
• Dry eyes
• Epidemic keratoconjunctivitis
• Episcleritis
• Iritis and uveitis
• Pharyngoconjunctivital fever
• Scleritis
• Squamous cell carcinoma
• Subconjunctival hematoma