Serologic Testing for syphilis - Letter from Matt Golden, MD. Director of PHSKC STD Control Program [12/09] - UW Net ID required
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General observations on HIV-infected patients with syphilis:
- Case reports suggest that the unusual clinical manifestations of syphilis may be more common (e.g. overlap of primary & secondary manifestations) and the course more rapid in patients with HIV infection.
- Though above not corroborated in prospective studies, case reports have largely driven the hypotheses that among patients coinfected with HIV and T pallidum:
- Mucocutaneous lesions may be more severe or numerous,
- Symptomatic neurosyphilis may be more likely to develop,
- Latency period before the development of meningovascular syphilis may be shorter,
- Efficacy of standard therapy for early syphilis may be reduced.
- HIV-infected patients can have atypical serologic responses. More typical is higher-than-expected RPR titers (e.g. 1:128). More rare: false negative and delayed onset of seroreactivity. Biologic false positives can occur (treponemal test negative), esp. if polyclonal gammopathy present.
- The “serofast” state is not uncommon among HIV-infected persons. It is the persistence of a reactive nontreponemal syphilis test, usually 1:16 or less, with variation no greater than 1 to 2 dilutions over time, despite adequate therapy and no evidence of reexposure.
- NOTE: Reinfection may be difficult to rule out in some patients, and reactivation or relapse of a previously treated infection is also possible in a person with HIV infection.
General treatment principles – areas of consensus [ CDC STD 2010 Guidelines]
- Long-acting penicillin G is treatment of choice:
- Benzathine penicillin G (Bicillin LA) 2.4 million U intrasmuscularly x 1 should be used in all cases for incubating, primary, secondary or early latent syphilis with no evidence of neurologic involvement.
- For late latent or syphilis of unknown duration:
- For late latent or syphilis of unknown duration without neurologic symptoms and/or negative CSF examination, then benzathine PCN G should be given as 7.2 million IU IM as 3 doses of 2.4 million IU in successive weeks.
- If CSF without evidence of neurosyphilis (CSF WBC>20/μL or reactive CSF VDRL), then benzathine PCN G should be given as 7.4 million IU IM as 3 doses of 2.4 million IU in successive weeks.
- Neurosyphilis (or syphilitic eye or auditory disease):
- Aqueous crystalline penicillin G 18-24 million U IV per day, dosed as continuous infusion or q4h, x 14 days
- Procaine penicillin 2.4 million U per day IM + Probenecid 500 mg PO QID x 14 days
- Doxycycline is an oral alternative and reserved only for patients who are truly penicillin-allergic – oral agents should never be used for neurosyphilis or pregnant patients with syphilis.
- Azithromycin, though it has shown promise in early syphilis, should not be used because of reported resistance.
- Confirmation of post-treatment serologic response:
- NOTE: Nontreponemal test antibody titers (RPR or VDRL) usually correlate with disease activity. Sequential serologic tests should be performed by same testing method (RPR or VDRL) & preferably by same lab.
- Follow-up of RPR or VDRL titer recommended at 3, 6, 9, 12 and 24 months after therapy.
- Appropriate response to treatment = 4-fold decrease in titer (2 dilutions) in 6 months.
- When do you perform a lumbar puncture to examine CSF?
- Any patient with syphilis who has neurologic complaints (includes ophthalmic or otologic complaints as well as cranial nerve palsy, meningitis, stroke, altered mental status or loss of vibratory sensation).
- Evidence of active tertiary syphilis (e.g., aortitis and gumma);
- All patients with treatment failure defined as:
- Recurrence or persistence of symptoms
- Lack of a 4-fold decrease in RPR titers after 12 months in early syphilis, 24 months in late syphilis
- 4-fold increase in RPR titers at any time after treatment
- More controversial: any asymptomatic HIV+ patient with RPR titer >1:32 or CD4 count <350.
- If you think your patient needs an LP, contact Trudy Jones, ARNP who can perform the LP and enroll patient in Christina Marra’s syphilis study [link]. Need UW ID to log in.
Zetola , NM and Klausner JD. Syphilis and HIV infection: an update. Clin Infect Dis 2007; 44:1222-8.
Workowski KA, Berman SM. Sexually transmitted diseases treatment guidelines, 2006. MMWR Recomm Rep 2006; 55:1–94.
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