Serologic tests—both nontreponemal and treponemal—are the mainstays of diagnosis; changes in antibody titers can also be used to monitor response to therapy.
- Nontreponemal serologic tests that measure IgG and IgM antibodies to a cardiolipin-lecithin-cholesterol antigen complex (e.g., rapid plasma reagin [RPR], Venereal Disease Research Laboratory [VDRL]) are recommended for screening or for quantitation of serum antibody. After therapy for early syphilis, a persistent fall in titer by ≥4-fold is considered an adequate response.
- Treponemal tests, including the agglutination assay (e.g., the Serodia TP-PA test), the fluorescent treponemal antibody-absorbed (FTA-ABS) test, and treponemal enzyme or chemiluminescence immunoassays (EIAs/CIAs), are used to confirm results from nontreponemal tests and should not be used as a screening test because of high false-positive rates. Results remain positive even after successful treatment.
- LP is recommended for pts with syphilis and neurologic signs or symptoms, an RPR or VDRL titer ≥1:32, or suspected treatment failure and for HIV-infected pts with a CD4+ T cell count <350/µL.
- - CSF exam demonstrates pleocytosis (>5 WBCs/µL) and increased protein levels (>45 mg/dL). A positive CSF VDRL test is specific but not sensitive; an unabsorbed FTA test is sensitive but not specific. A negative unabsorbed FTA test excludes neurosyphilis.
- Pts with syphilis should be evaluated for HIV disease.
Treatment: Syphilis - See Table 83-3 for treatment recommendations.
- The Jarisch-Herxheimer reaction is a dramatic reaction to treatment that is most common with initiation of therapy for primary (~50% of pts) or secondary (~90%) syphilis. The reaction is associated with fever, chills, myalgias, tachycardia, headache, tachypnea, and vasodilation. Symptoms subside within 12-24 h without treatment.
- Response to treatment should be monitored by determination of RPR or VDRL titers at 6 and 12 months in primary and secondary syphilis and at 6, 12, and 24 months in tertiary or latent syphilis.
- - HIV-infected pts should undergo repeat serologic testing at 3, 6, 9, 12, and 24 months, irrespective of the stage of syphilis.
- - Re-treatment should be considered if serologic responses are not adequate (a persistent antibody fall by ≥4-fold) or if clinical signs persist or recur. For these pts, CSF should be examined, with treatment for neurosyphilis if CSF is abnormal and treatment for late latent syphilis if CSF is normal.
- - In treated neurosyphilis, CSF cell counts should be monitored every 6 months until normal. In adequately treated HIV-uninfected pts, an elevated CSF cell count falls to normal in 3-12 months.
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