NATURAL HISTORY & PRINCIPLES OF DIAGNOSIS & TREATMENT
Syphilis is a complex infectious disease caused by Treponema pallidum, a spirochete capable of infecting almost any organ or tissue in the body and causing protean clinical manifestations (Table 34–1). Transmission occurs most frequently during sexual contact (including oral sex); sites of inoculation are usually genital but may be extragenital. The risk of acquiring syphilis after unprotected sex with an individual with infectious syphilis is approximately 30–50%. Rarely, it can also be transmitted through nonsexual contact, blood transfusion, or via the placenta from mother to fetus (congenital syphilis). The immunologic response to infection is complex, but it provides the basis for most clinical diagnoses. The infection induces the synthesis of a number of antibodies, some of which react specifically with pathogenic treponemes and some with components of normal tissues (see below). If the disease is untreated, in most cases these immune reactions fail to eradicate existing infection and may contribute to tissue degeneration in the late stages. Patients treated early in the disease are fully susceptible to reinfection.
Table 34–1.Stages of syphilis and common clinical manifestations. |Favorite Table|Download (.pdf) Table 34–1. Stages of syphilis and common clinical manifestations.
The natural history of acquired syphilis is generally divided into two major clinical stages: early (infectious) syphilis and late syphilis. The two stages are separated by a symptom-free latent phase during the first part of which (early latency) infectious lesions can recur. Infectious syphilis includes primary lesions (chancre and regional lymphadenopathy) appearing during primary syphilis, secondary lesions (commonly involving skin and mucous membranes, occasionally bone, central nervous system [CNS], or liver) appearing during secondary syphilis, relapsing lesions during early latency, and congenital lesions. The hallmark of these lesions is an abundance of spirochetes; tissue reaction is usually minimal. Late syphilis consists of so-called benign (gummatous) lesions ...