Syphilis in pregnancy — structured oral station (12 minutes)

Opening prompt — "What is your immediate management?"

Model response, in this order: ^[1]

• "I would confirm the diagnosis with a treponemal test if not already done — a TP-PA or a chemiluminescent immunoassay — and stage the disease clinically. I would take a focused sexual and social history, examine for a chancre, rash, palmar or plantar lesions and condylomata lata, and arrange combined screening for HIV, hepatitis B and C, chlamydia, gonorrhoea and trichomoniasis."^[1]
• "I would involve the multidisciplinary team — the sexual health or infectious diseases physician, the midwife, and the public health unit for partner notification and contact tracing."^[1]
• "The priority is to treat early enough and adequately enough to prevent congenital syphilis, with benzathine penicillin G as the only recommended agent."^[1]

Examiner is listening for: the staging cascade, the combined coinfection screen, and the named agent and drug-only rationale. ^[1]

Probe 1 — "How do you stage her syphilis and what treatment does the stage dictate?"

• "Syphilis is staged as primary (chancre), secondary (rash, palms and soles, condylomata lata), early latent (under one year, asymptomatic), late latent (over one year or unknown duration), tertiary and neurosyphilis. The stage dictates the number of benzathine doses."^[1]
• "Primary, secondary and early latent syphilis take a single dose of benzathine penicillin G 2.4 million units intramuscularly. Late latent, unknown-duration and tertiary syphilis take three weekly doses, a total of 7.2 million units."^[1]
• "The Kaminiów 2026 randomised trial confirmed no added benefit from intensifying early syphilis in pregnancy with three weekly doses — the standard remains a single dose."^[1][3]

Probe 2 — "She reports a penicillin allergy. How do you handle it?"

• "Penicillin is the only recommended treatment for syphilis in pregnancy — there is no proven alternative. Doxycycline and tetracycline are contraindicated in pregnancy, and azithromycin is precluded by resistance."^[1]
• "A penicillin-allergic pregnant woman undergoes desensitisation — typically oral desensitisation over a few hours in a monitored setting — followed by treatment with the appropriate benzathine regimen. The allergy history is clarified with the woman, but the pathway to penicillin is unchanged."^[1]
• "Ceftriaxone is not the pregnancy standard for syphilis."^[1]

Probe 3 — "She is treated in the second half of pregnancy. What is the Jarisch-Herxheimer reaction and how do you manage it?"

• "The Jarisch-Herxheimer reaction is an acute cytokine-mediated febrile reaction triggered by the lysis of spirochaetes on treatment. In the Klein 1990 cohort, it complicated about 45% of treatments overall and 60% of treatments for secondary syphilis."^[2]
• "The timeline is onset 2 to 8 hours after treatment, peak at 6 to 12 hours, resolution by 16 to 24 hours. In pregnancy it triggers uterine contractions and reduced fetal movements in roughly two-thirds of reactors, with transient late decelerations on the CTG."^[2]
• "I counsel the woman to seek obstetric attention for fever, contractions or reduced fetal movements, and I monitor with maternal observations and a CTG through the 24-hour window. The reaction is monitored, not avoided — the risk of untreated syphilis vastly exceeds the reaction risk. Corticosteroid prophylaxis is not supported."^[1][2]

Probe 4 — "How do you confirm an adequate response, and what do you do if the titre rises later?"

• "Adequate response is a fourfold — two-dilution — decline in the non-treponemal titre (RPR or VDRL), assessed at 6 to 12 months for early syphilis. Treponemal tests do not monitor response."^[1]
• "A rising titre after an adequate decline means reinfection or treatment failure. I re-stage, re-test for HIV, re-test the partner, and re-treat with three weekly doses of benzathine penicillin G. I consider CSF examination if neurosyphilis is suspected."^[1]

Communication probe — "She asks: 'Will my baby be okay?'"

• "I would say: with adequate treatment at least 30 days before delivery, the risk of congenital syphilis falls dramatically. I will treat you today, monitor you and the baby through the treatment reaction, follow your blood tests to confirm the treatment has worked, and plan the birth and the baby's check with the paediatric team. The most important thing is that we treat early and adequately, and we will."^[1]

Examiner is listening for: honest outcome framing, the timing fact (30 days before delivery), the monitoring plan, and the multidisciplinary team. ^[1]