Thursday, December 23, 2010

Chlamydial & Gonococcal Conjunctivitis

Chlamydial (inclusion) conjunctivitis typically affects sexually active teens and young adults and is the most frequent infectious cause of neonatal conjunctivitis in the U.S. The Centers for Disease Control (CDC) recognizes chlamydia as one of the major sexually transmitted pathogens, estimating approximately three million new cases per year. Women seem to be more susceptible than men. The incidence of infection seems to be directly related to sexual activity and geography, with urban populations having higher incidences. The incidence in pregnant women overall is 4 to 10 percent.

Diagnosis of inclusion conjunctivitis is often difficult. Many times there are little, if any, symptoms. Infants whose mothers have untreated chlamydial infection have a 30 to 40 percent chance of developing neonatal chlamydial conjunctivitis. Systemic signs and symptoms may include a history of vaginitis, pelvic inflammatory disease or urethritis.

Ocular signs and symptoms include the chief complaint that an eye infection has persisted for over three weeks despite treatment with topical antibiotics. Conjunctival injection, superficial punctate keratitis, superior corneal pannus, peripheral subepithelial infiltrates, iritis and follicles (most dense in the inferior cul-de-sac) may all be present. Mucopurulent, stringy or mucus discharge is common. A palpable preauricular node is almost always present.

Gonococcal conjunctivitis, sometimes referred to as hyperacute conjunctivitis, is also a sexually transmitted ocular disease. While sexual contact is the customary route of transmission, even casual interaction with infected individuals has been reported as a cause. Newborn infants may acquire the infection by passing through an infected birth canal. Systemically, gonococcal infections are associated with infection of the urethra, cervix and rectum. Symptoms vary from nothing to discharge and irritation.

This unusually contagious ocular disease typically presents as a hyperacute red eye of less than four weeks duration with foreign body sensation; the eye may be “glued” shut with severe purulent discharge. The conjunctivitis has an incubation period of two to seven days. Conjunctival papillae, superficial punctate keratitis and marked chemosis are almost always present. Subconjunctival hemorrhage (hemorrhagic conjunctivitis), pseudomembrane or true membrane formation and preauricular lymph nodes are usually present. In chronic, recalcitrant or severe cases, peripheral subepithelial corneal infiltrates may occur, leading to marginal ulceration with anterior uveitis.

Chlamydia trachomatis is an intracellular parasite that contains its own DNA and RNA. The sub-group A causes chlamydial infections, the serotypes A, B, Ba and C cause trachoma, and serotypes D through K produce adult inclusion conjunctivitis. The mode of ocular transmission may be hand contact from a site of genital infection to the eye, laboratory accidents, a mother infecting the newborn, shared cosmetics and occasionally an improperly chlorinated hot tub.

Diagnostic testing for chlamydia is expensive and difficult to interpret. The preferred method of identification is to culture the organism. Conjunctival scrapings for Giemsa staining will show intracytoplasmic inclusion bodies in epithelial cells, polymorphonuclear leukocytes and lymphocytes.

The infectious organism in gonococcal conjunctivitis is Neisseria gonorrhoeae, a gram-negative, intracellular diplococcus capable of invading an intact mucosal membrane. Transmission is generally by direct or indirect sexual contact or contact with an infected individual. N. gonorrhoeae’s ability to penetrate an intact corneal epithelium makes the risk of corneal infection and ulceration high.

In treating chlamydial conjunctivitis, many doctors consider oral tetracycline 250 to 500mg q.i.d. for three weeks the treatment of first choice. But since tetracycline must be administered one hour before or after meals to avoid gastrointestinal side effects and interference of dairy products with its efficacy, other oral medications may be more appropriate. Amoxacillin and erythromycin 250 to 500mg q.i.d. for three weeks or doxycycline 100mg b.i.d. for one week are acceptable alternatives.

Currently, the drug of choice is azithromycin (Zithromax). Taken as a 1 gram dose, by mouth, one time, it has been documented as being as effective for the treatment of genital chlamydial infection as doxycycline. Topical therapy is adjunctive and includes erythromicin, tetracycline or sulfacetamide t.i.d. for three weeks as well.

Patients with gonococcal conjunctivitis require immediate conjunctival scrapings for culture and sensitivity testing. Medical management of gonococcal infection begins with an intramuscular loading dose of ceftriaxone 1g. Ideally, the patient should be hospitalized and given one gram of ceftriaxone intravenously within 12 to 24 hours. Following discharge, resume treatment with either erythromicin 250 to 500mg p.o. q.i.d., tetracycline 250 to 500mg p.o. q.i.d. or doxycycline 100mg p.o. b.i.d.

Begin ocular management with saline lavage to clear the mucopurulent debris from the lids and conjunctiva. A topical fluoroquinolone (ofloxacin or ciprofloxacin) is appropriate if corneal infection occurs. However, because gonococcal conjunctivitis does not respond to topical antibiotics, topical therapy is usually not indicated.


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