C. TRACHOMATIS INFECTIONS
TRACHOMA AND ADULT INCLUSION CONJUNCTIVITIS (AIC)
- Trachoma is a chronic conjunctivitis caused by C. trachomatis serovars A, B, Ba, and C. Transmission occurs through contact with ocular discharge from infected pts, which is sometimes transferred by flies.
- AIC is an acute eye infection occurring in adults exposed to infected genital secretions and in their newborns. This infection is caused by sexually transmitted C. trachomatis strains, usually serovars D–K.
Trachoma is a leading cause of preventable infectious blindness, with ∼6 million pts having been affected. In the hyperendemic regions of northern and sub-Saharan Africa, the Middle East, and parts of Asia, the prevalence of trachoma is ∼100% by the third year of life. Reinfection and persistent infection are common.
Both trachoma and AIC present clinically as conjunctivitis characterized by small lymphoid follicles in the conjunctiva; trachoma usually starts insidiously before 2 years of age.
- With progression of trachoma, there is inflammatory leukocytic infiltration and superficial vascularization (pannus formation) of the cornea.
- Scarring eventually distorts the eyelids, turning lashes inward and abrading the eyeball (trichiasis and entropion).
- The corneal epithelium eventually ulcerates, with subsequent scarring and blindness.
- Destruction of goblet cells, lacrimal ducts, and glands causes dry-eye syndrome (xerosis), with resultant corneal opacity and secondary bacterial corneal ulcers.
- AIC is an acute unilateral follicular conjunctivitis with preauricular lymphadenopathy and presents similarly to acute conjunctivitis due to adenovirus or HSV.
- Corneal inflammation is evidenced by discrete opacities, punctate epithelial erosions, and superficial corneal vascularization.
- Left untreated, the disease may persist for 6 weeks to 2 years.
Clinical diagnosis of trachoma is based on the presence of two of the following signs: lymphoid follicles on the upper tarsal conjunctiva, typical conjunctival scarring, vascular pannus, or limbal follicles.
- Intracytoplasmic chlamydial inclusions are found in 10–60% of Giemsa-stained conjunctival smears from children with severe inflammation.
- Chlamydial nucleic acid amplification tests are more sensitive in detecting infection.
- AIC responds to azithromycin (a single 1-g oral dose) or doxycycline (100 mg PO bid for 7 days). Treatment of sexual partners is needed to prevent ocular reinfection and chlamydial genital disease.
C. TRACHOMATIS INFECTIONS
is a sample topic from the Harrison's Manual of Medicine
To view other topics, please sign in or purchase a subscription.
Harrison’s Manual of Medicine 20th edition provides 600+ internal medicine topics in a rapid-access format. Download Harrison’s App to iPhone, iPad, and Android smartphone and tablet. Complete Product Information.