Syphilis remains highly sensitive to antibiotics such as penicillin, a short course of which is sufficient to treat all stages of the disease. Serology is the mainstay of diagnosis. Serologic tests for syphilis include nontreponemal antibody tests and antitreponemal antibody tests. Nontreponemal tests measure antibody to cardiolipin, an antigen that is present in both host tissues and the treponemal cell wall. These antibodies are detected by the rapid plasma reagin (RPR) and Venereal Disease Research Laboratory (VDRL) tests. Nontreponemal antibody tests are usually positive by 4 to 6 weeks of infection and are strongly positive in the secondary phase of infection. However, nontreponemal antibody test results may revert to negative during the tertiary phase or, conversely, may on occasion be persistently positive in some patients after successful treatment. Two additional points regarding nontreponemal antibody tests deserve emphasis:
Nontreponemal antibody test results often are negative during the early stages of disease, even in the presence of a primary chancre. If there is a high degree of suspicion, these tests should be repeated in a few weeks.
As many as 15% of positive VDRL test results are unrelated to syphilis. These false-positive results, which may be acute (transient) or chronic (persistent), increase in frequency with age and are associated with a variety of conditions, including the antiphospholipid antibody syndrome (Chapter 4).
Treponemal antibody tests also become positive within 4 to 6 weeks after an infection but (unlike those for nontreponemal antibody tests) they usually remain positive indefinitely, even after successful treatment. Historically, treponemal antibody tests have been used to confirm the diagnosis of syphilis in those with a positive nontreponemal antibody test. However, thanks to recent test improvements, some centers have reversed this algorithm and now use treponemal antibody tests for screening and nontreponemal antibody tests to confirm the diagnosis. As with all serologic tests for infection, certain pitfalls must be considered when interpreting these tests, including the timing of the test relative to the infection (e.g., too early for an antibody response to have been mounted) and the confounding influence of altered immunity, particularly in those who are HIV-infected.
http://ebooksmedicine.net
SyphilisiscausedbyT. pallidum andhasthreestages.
Primarysyphilis:Apainlesslesioncalledachancre developsontheexternalgenitaliaalongwithregionallymphnodeenlargement.
Secondarysyphilis:Generalizedlymphadenopathyandmucocutaneouslesionsthatmaybemaculopapularortaketheformofflatraisedlesionscalledcondylomata lata.
Tertiarysyphilis:Maycauseproximalaortitisandaorticinsufficiency;mayinvolvethebrain,meninges,andthespinalcord;ormaycausefocalgranulomatouslesionscalledgummas inmultipleorgans.
Congenitalsyphilisiscausedbymaternaltransmissionofthespirochetesduringvaginalbirth,mostlyduringtheprimaryandsecondarystagesofdiseaseinthemother.Itmayleadtostillbirthorcausewidespreadtissueinjuryinliver,spleen,lung,bones,andpancreas.
Mostsyphiliticlesionsdemonstrateproliferativeendarteritisandaplasmacell–richinflammatoryinfiltrate.Gummashaveacentralareaofnecrosissurroundedbylymphoplasmacyticinfiltrates,activatedmacrophages,andfibrosis.
Thediagnosticmainstayisserologictesting.Nontreponemalantibodytests(VDRLandRPR)areusuallypositiveinearlydisease,butmaybenegativeinadvanceddisease.Treponemespecificantibodytestresultsbecomepositivelaterandremainpositiveindefinitely.