SYPHILIS SEROLOGY

SYPHILIS SEROLOGY

 

A. Human syphilis is caused by the spirochete Treponema pallidum. Antibodies against treponemal

antigens and nontreponemal cardiolipin antigens (Wasser-mann antigens) develop

and elicit a cell-mediated and humoral Ir, which results in the formation of immune complexes.

B. Disease. Sexual contact with infected persons is the most common form of transmission

of human syphilis. Transmission through blood or blood-product transfusion can occur

but is rare now because of effective pretransfusion testing. In addition, syphilis can be

passed from an infected pregnant woman to her fetus. There are four clinical stages of

disease.

1. Primary (early) syphilis. Inflammatory lesions (chancres) appear 2 to 8 weeks

after infection and last for 1 to 5 weeks. Serum tests for syphilis are positive

in 90% of patients after 3 weeks. The antibodies that develop are predominantly

IgM.

2. Secondary syphilis usually occurs 6 to 8 weeks after chancres first appear. This stage

is characterized by a generalized rash, and secondary lesions may develop in the eyes,

joints, or central nervous system (CNS). These lesions are highly contagious, but heal

spontaneously within 2 to 6 weeks. Serologic tests are positive in secondary syphilis.

Antibodies are mostly IgG.

3. The latent stage of syphilis is contagious and is generally considered to begin after

the second year of infection. There are no clinical symptoms, although serologic tests

are still positive. After 4 years, syphilis is not usually contagious; however, the disease

may still be transmitted from mother to fetus.

4. Tertiary syphilis is characterized by granulomatous lesions known as gummata. These

lesions may develop in skin, mucous membranes, joints, muscles, and bones, causing

little or no clinical problems. Approximately 80% of patients experience CNS involvement,

which can result in paralysis or dementia. Approximately 10% of patients develop

cardiovascular problems, which can result in aortic aneurysm.

C. Congenital syphilis. Syphilis can be transmitted to a fetus after the 18th week of gestation.

Treatment of the infected mother before the 18th week will prevent infection; treatment

after the 18th week will cure it.

 

D. Treatment. Syphilis is easily and effectively treated. Penicillin is the drug of choice, although

tetracycline or erythromycin can also be used. Treatment may or may not result in

serologic tests becoming nonreactive, depending on the stage of the disease at the time of treatment.