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Zorluk: ZorInfectious Diseases

A 35-year-old man comes to the clinic for a routine 6-month sexually transmitted infection screening. He is currently asymptomatic and has no somatic complaints. He reports having multiple male sexual partners. He has no known drug allergies and takes a daily tenofovir-emtricitabine regimen for HIV pre-exposure prophylaxis.

His medical history is significant for a diagnosis of primary syphilis 22 years ago, which was appropriately treated with a single intramuscular injection of benzathine penicillin G. At the time of that diagnosis, his Rapid Plasma Reagin (RPR) titer was 1:641:64. Six months after his treatment, the titer had decreased to 1:21:2.

Review of his medical records shows that during his last routine screening 66 months ago, his RPR titer remained stable at 1:21:2.

Today, his physical examination is unremarkable, with no evidence of chancre, mucosal lesions, maculopapular rash, or neurological abnormalities.

Laboratory results from today's visit:
HIV antigen/antibody test: Negative
RPR: Positive, titer 1:321:32
*Treponema pallidum* particle agglutination (TP-PA): Positive

Which of the following is the most appropriate next step in management?

  1. A
    Reassure the patient and observe, as these results reflect a serofast state
  2. Administer a single dose of intramuscular benzathine penicillin GCevap
  3. C
    Administer intramuscular benzathine penicillin G once weekly for 3 weeks
  4. D
    Perform a lumbar puncture for cerebrospinal fluid analysis
  5. E
    Prescribe oral doxycycline for 14 days

Cevap

The most appropriate management is to administer a single dose of intramuscular benzathine penicillin G.
The patient presents with an asymptomatic *Treponema pallidum* infection. His RPR has increased from a baseline of 1:21:2 (documented 66 months ago) to 1:321:32. A ≥4\ge 4-fold increase in a non-treponemal titer (e.g., 1:21:2 to 1:81:8, or in this case, a 1616-fold increase to 1:321:32) indicates a reinfection. Because he had a documented titer of 1:21:2 just 66 months ago, the duration of this new infection is definitively known to be less than one year. Therefore, he has early latent syphilis. The standard treatment for early latent syphilis (as well as primary and secondary syphilis) is a single dose of intramuscular benzathine penicillin G.

Adım Adım Çözüm

1
Evaluate the current non-treponemal (RPR) titer against the historical baseline.
The RPR titer increased from 1:21:2 (six months ago) to 1:321:32 (today), which is a 1616-fold increase.
A ≥4\ge 4-fold increase in RPR indicates a new, active syphilis infection (reinfection) rather than a historical serofast state.
2
Determine the clinical stage of the syphilis reinfection.
The patient is asymptomatic, meaning the infection is in a latent stage. Because he had a stable low titer just 66 months ago, the new infection was acquired within the past year.
Latent syphilis acquired within the preceding 1212 months is classified as early latent syphilis.
3
Select the appropriate pharmacotherapy for early latent syphilis.
The standard of care is a single dose of intramuscular benzathine penicillin G.
Unlike late latent syphilis (which requires 33 weekly doses), early latent syphilis is effectively treated with a single intramuscular injection.

Anahtar Kavram

Early latent syphilis (an asymptomatic infection acquired within the past year, proven by a ≥4\ge 4-fold RPR rise within 1212 months) is treated with a single dose of intramuscular benzathine penicillin G.
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Infectious Diseases

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