Sexually Transmitted Infections

Matthew Melton

Evaluation: Gonorrhea, Chlamydia, Trichomonas 

  • Microbial diagnosis is preferred rather than clinical diagnosis alone 
  • Test of choice: NAAT of the first-void urine in men; NAAT of vaginal swab in women 
  • NAAT of pharyngeal or rectal swab should also be performed in patients with reported symptoms and recent sexual exposure. Note this is also routine testing in patients on PrEP. 
  • Routine screening should be offered to sexually active patients, as many are asymptomatic 
    • Women age < 25 years should undergo annual G/C screening 
    • MSW without HIV infection should undergo G/C screening if increased risk 
    • MSM without HIV infection should undergo at least annual G/C screening 
  • NAATs can detect both LGV and non-LGV chlamydia, but cannot distinguish between them 
  • ALWAYS Check CDC guidelines to confirm treatment strategy given emerging resistance: https://www.cdc.gov/std/treatment-guidelines/default.htm

Chlamydia

Background 

  • Cause: gram negative bacteria Chlamydia trachomatis 
  • Most individuals asymptomatic. Spectrum of disease: urethritis, cervicitis, PID, conjunctivitis, perihepatitis (Fitz-Hugh-Curtis syndrome), PNA, proctitis, epididymitis, reactive arthritis, pharyngitis, lymphogranuloma venereum (LGV), endemic trachoma 
  • DDx: Neisseria gonorrhoeae, Trichomonas vaginalis, Mycoplasma genitalium

Management

  • Doxy 100mg BID x 7 days. Alternative (for allergies/severe CIs): azithro (1g PO x 1), levofloxacin (500mg PO daily x7 days), and ofloxacin (300mg BID PO x7 days) 
    • Receptive anal intercourse with positive rectal chlamydia NAAT and Sxs (bloody anal discharge, tenesmus, ulceration) – LGV therapy (doxycycline 100mg BID x21d rather than 7) o Potential or confirmed exposure within the last 1-2 weeks – treat empirically. 
    • Empiric therapy for gonorrhea should be given to pts unless NAAT is negative. 
    • Persistent symptoms, confirmed infection, and who already underwent appropriate treatment, likely have a re-infection, rather than treatment failure. Retest 
  • Abstain from sexual contact until Tx course complete, no need for test of cure UNLESS pregnant 
  • Partners should undergo screening and treatment. Expedited partner therapy (giving pt script for their partner(s)) IS legal in TN and can be used when partner unlikely to seek care

Gonorrhea

Background 

  • GNC Neisseria gonorrhoeae 
  • Spectrum of disease: urethritis, cervicitis, epididymitis, proctitis, pharyngeal infections, conjunctivitis, PID, and disseminated gonococcal infection

Management 

  • CTX (<150kg 500mg IM; >150kg 1g IM) 
    • Same for pharyngitis or conjunctivitis 
  • CTX allergies: Azithromycin + Gentamicin OR Gemifloxacin discuss with ID. 
  • Treatment for chlamydia unless excluded with molecular testing. 
  • Persistent Sxs despite Tx suspect resistant gonorrhea or Mycoplasma genitalium. Test with Cx and antimicrobial susceptibility testing (with or without NAAT). 
  • Partners should undergo screening and Tx. Expedited Partner Therapy is NOT legal for gonorrhea in TN. 
  • Abstain from sexual contact for 7d following Tx, test of cure not generally warranted

Trichomonas

Background 

  • Flagellated protozoan Trichomonas vaginalis
  • Most individuals are asymptomatic, although there is a spectrum of disease: urethritis or cystitis, vaginitis, cervicitis, pelvic inflammatory disease
  • Most common non-viral sexually transmitted infection worldwide

Management 

  • Female: Metronidazole 500mg BID x7d 
  • Male: Single dose of 2g of Metronidazole. If failure from re-exposure to untreated partner, repeat. If failure NOT from re-exposure to untreated partner, tinidazole 2g x1 OR metronidazole 500mg BID x7d 
  • High rates of co-infection w/ other STI’s full screening panel if Trichomonas confirmed 
  • Partners should undergo screening and treatment. Expedited Partner Therapy is NOT legal for Trichomonas treatment in TN. 
  • Abstain from sexual contact until pt and their sexual partner(s) completed Tx and are asymptomatic. Women should undergo retesting ~3M to ensure cure

Syphilis

Background 

  • Caused by the spirochete, Treponema pallidum. Transmitted by direct contact with infectious lesion during sex (condoms do NOT provide full protection). 
  • High rate of HIV co-infection among MSM with syphilis. Can readily cross the placenta

Evaluation 

  • Test all pts with signs/symptoms and pts who are at increased risk (sexual partner with early syphilis, MSM, HIV, high risk sexual behaviors, commercial sex work, incarceration) 
  • HIV testing for all patients that test positive 
  • Pregnant pts should be screened for syphilis 
  • Two types of serologic tests: treponemal-specific tests (FTA-ABS, MHA-TP, TPPA, TP-EIA, CIA) and nontreponemal tests (RPR, VDRL, TRUST). VUMC utilizes Reverse Sequence Algorithm due to enhanced automaticity of testing and high number of false negatives in traditional algorithm 
    • Treponemal tests typically remain positive for life following infection 
    • Nontreponemal is used to assess for cure and should decline after treatment. A new 4-fold rise after treatment is concerning for new infection. 
    • False negatives: immunocompromised (particularly humoral immunity) 
    • False positives: autoimmune diseases, pregnancy, other infections, IVDU 
  • Neurosyphilis can occur at any time after infection. All newly diagnosed pts with syphilis should have a full neurologic exam and if any abnormalities should have an LP sent for CSF-VDRL (specific, but not as sensitive) with reflex to FTA-ABS (sensitive, but not as specific) 
  • Any pts with syphilis and vision changes should get an ophthalmology evaluation

Non-treponemal

+Treponemal

-Treponemal
+Non-treponemal Diagnostic of syphilis (completely new or potentially re-infected) Likely false positive
-Non-treponemal Likely history of successfully treated syphilis Likely not syphilis or false negative (due to prozone effect*)
*Prozone effect: overabundance of Abs and they interfere with formation of Ab/Ag complex >> no agglutination

Management 

  • When positive Treponemal Ab + low positive or negative RPR, it is important to determine prior testing and treatment. 
    • For obtaining historical syphilis titers and past treatment records, email syphilis.history@tn.gov with responses to be expected same day or next business day 
  • To assess treatment efficacy, goal of a fourfold decrease in titer after treatment 
  • Offer HIV PrEP for syphilis positive, HIV negative patients

Stage

Symptoms

Treatment

Treatment Alternatives
Primary Painless chancre at inoculation site, regional LAD PCN G benzathine 2.4 MU IM x1
(**If available limited by abx shortages, can discuss w/ pharmacy using alternatives as 1st line) 		Doxy 100mg BID x 14d
or
CTX 1-2g qd x 10-14d
or
Tetracycline 500mg QID x 14d
or
Amoxicillin 3g BID and probenecid 500mg BID x14d
Secondary Fever, malaise, rash (diffuse, including palms/soles), alopecia, hepatitis, mucous patches, condyloma, pharyngitis
Early Latent No symptoms. Occurs within one year of initial infection.
Tertiary CV system, gummatous dx PCN G benzathine 2.4 MU IM weekly x3w
(**If available limited by abx shortages, can discuss w/ pharmacy using alternatives as 1st line) 		Doxy 100mg BID x 4w
or
CTX 2g daily x 10-14d
Late Latent OR
Syphilis of Unknown Duration 		Infected, but no symptoms.
Occurs >1 year after initial infection. Refer to last known negative test
Neurosyphilis
or
Ocular Syphilis 		Can occur at any time.
Early: asymptomatic OR meningitis, vision loss, hearing loss
Late: brain and spinal cord manifestations (dementia, tabes dorsalis)
Treat ocular syphilis like neurosyphilis 		Aqueous PCN G 4 MU IV q4h x10-14d PCN G procaine 2.4 MU IM daily and probenecid 500mg QID x 10-14d

If PCN allergic, desensitize or CTX 2g qd x10-14d
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