How should a 60-year-old patient with lab-positive syphilis and no symptoms be treated, considering the distinction between early latent and late latent syphilis?

Treatment Approach for Lab-Positive Asymptomatic Syphilis in a 60-Year-Old

Treat this patient as late latent syphilis with benzathine penicillin G 2.4 million units IM weekly for three consecutive weeks (total 7.2 million units) unless you can definitively establish that the infection was acquired within the past year. 1, 2

Determining Early vs. Late Latent Syphilis

The critical distinction hinges on whether infection occurred within the preceding 12 months:

Early latent syphilis (infection <1 year):

• Requires documented negative serology within the past year, or
• Clear history of exposure or symptoms within the past 12 months, or
• Documented seroconversion within the past year 1

Late latent syphilis (infection ≥1 year or unknown duration):

• Cannot establish infection timeline within past year
• No documented negative serology in past 12 months
• Unknown duration of infection 1, 2

In a 60-year-old with no symptoms and no clear timeline, you should presume late latent syphilis and treat accordingly. 1, 2

Treatment Regimens

Late Latent Syphilis (Most Likely Scenario)

• Benzathine penicillin G 2.4 million units IM once weekly for 3 consecutive weeks (total 7.2 million units) 1, 2

Early Latent Syphilis (Only if Definitively Established)

• Benzathine penicillin G 2.4 million units IM as a single dose 1, 2

Penicillin Allergy

• Doxycycline 100 mg orally twice daily for 28 days for late latent syphilis 1, 2, 3
• Doxycycline 100 mg orally twice daily for 14 days for early latent syphilis 3, 2
• CSF examination must be performed before using non-penicillin therapy to exclude neurosyphilis 1

Essential Pre-Treatment Evaluation

Before initiating treatment, assess for indicators requiring CSF examination:

Perform lumbar puncture if ANY of the following are present:

• Neurologic or ophthalmic signs/symptoms
• Serum nontreponemal titer ≥1:32 (unless infection duration known to be <1 year)
• HIV infection
• Evidence of tertiary syphilis (aortitis, gumma, iritis)
• Treatment failure
• Planning non-penicillin therapy (unless infection duration known to be <1 year) 1

HIV testing is mandatory for all patients with syphilis. 1, 2

Common Pitfalls to Avoid

Do not assume early latent syphilis without documentation. The default position for asymptomatic patients without clear timeline is late latent syphilis requiring three weekly injections. 1, 2

Do not rely solely on high nontreponemal titers (≥1:32) to classify as early syphilis for treatment purposes. While titers ≥1:32 may suggest early infection for partner notification purposes, they should not determine treatment duration—you still treat based on documented infection timeline. 1

Do not skip CSF examination in high-risk scenarios. Asymptomatic neurosyphilis occurs in a subset of patients, and standard latent syphilis treatment may be inadequate for CNS disease. 1

Follow-Up Monitoring

• Quantitative nontreponemal tests (RPR or VDRL) at 6,12, and 24 months 1, 2
• Treatment failure is defined as: fourfold increase in titer, failure of initially high titer (≥1:32) to decline fourfold within 12-24 months, or development of new symptoms 1
• Re-evaluate for neurosyphilis and re-treat if treatment failure occurs 1

Partner Management

• Long-term sex partners should be evaluated clinically and serologically 1
• Sexual transmission occurs only with mucocutaneous lesions, which are uncommon after the first year of infection 1, 4

Jarisch-Herxheimer Reaction

Counsel the patient about possible acute febrile reaction with headache and myalgia within 24 hours of treatment. Antipyretics may be recommended, though no proven prevention methods exist. 1, 2