AIM OSCE / OSPE • FINAL YEAR MBBS
Station 10 — Sexually Transmitted Infection / New-Onset Genital Lesion Clinical Approach
Renal Module • Medicine / Nephrology
Rapid Revision • Clinical Skills • Practical Skills • Viva
🎯 Candidate Task
An adult patient presents with a newly developed genital lesion following recent sexual contact. Take a focused and confidential history, describe the relevant clinical examination, identify the likely sexually transmitted infections, and explain your diagnostic and initial management approach to the examiner.
⚡ Model Station Answer
History: Establish lesion onset, pain, discharge, recurrence, associated symptoms, sexual exposure and previous STIs using a confidential, nonjudgmental approach.
Examination: Assess lesion type, number, tenderness, distribution and inguinal lymph nodes, with consent and a chaperone.
Interpretation: A painless indurated ulcer suggests primary syphilis; painful grouped vesicles or ulcers suggest genital herpes; soft painful ulcers may suggest chancroid.
Investigations: Syphilis serology, HSV lesion PCR, HIV testing and other STI tests according to exposure and clinical findings.
Management: Provide cause-directed treatment, advise temporary sexual abstinence, arrange appropriate partner notification and testing, and ensure confidential follow-up.
🔎 How to Perform / Approach
- Introduce and establish confidentiality:
Confirm the patient’s identity, obtain consent and explain privacy and confidentiality. Use respectful, nonjudgmental language and ensure a private setting. - Take a focused lesion history:
Ask about onset, duration, pain, itching, vesicles, ulceration, discharge, recurrence and progression. Enquire about fever, dysuria, urethral discharge and inguinal swelling. - Assess sexual and relevant medical history:
Ask sensitively about recent partners, types of sexual contact, condom use, previous STIs, partner symptoms and previous treatment. Enquire about HIV status, medication allergies and pregnancy possibility where relevant. - Describe the focused examination:
Obtain specific consent and offer a chaperone. Assess lesion location, number, morphology, tenderness, induration and surrounding inflammation. Examine inguinal lymph nodes and look for other relevant mucocutaneous lesions. - Classify and interpret the clinical presentation:
Painless indurated ulcer suggests syphilis; painful grouped vesicles or shallow ulcers suggest herpes; painful soft ulcers with tender lymphadenopathy may suggest chancroid. Also recognize genital warts and urethral discharge syndromes. Appearance alone is insufficient for definitive diagnosis. - Select investigations and treatment:
Request syphilis serology (treponemal and nontreponemal tests), HSV PCR from an active lesion, HIV testing and gonorrhea/chlamydia NAAT when indicated. Treat confirmed or strongly suspected infections according to clinical assessment: benzathine penicillin G for early syphilis, acyclovir/valacyclovir for genital herpes and ceftriaxone-based treatment for gonorrhea as indicated. - Provide counselling and follow-up:
Explain the diagnosis without judgment, recommend avoiding sexual contact until appropriate treatment and lesion healing, discuss condoms and prevention, arrange appropriate partner evaluation and treatment, and review investigation results. Offer hepatitis B vaccination when indicated.
📝 Important Viva Questions
Q1. How are common sexually transmitted infections classified clinically?
Answer: Common presentations include genital ulcer disease (syphilis, herpes, chancroid), urethral/cervical discharge syndromes (gonorrhea, chlamydia) and genital warts (HPV).
Q2. How do primary syphilis and genital herpes typically differ clinically?
Answer: Primary syphilis commonly produces a painless indurated chancre, whereas genital herpes typically causes painful grouped vesicles or shallow ulcers. Atypical presentations occur.
Q3. Which investigations should be considered in a patient with a new genital ulcer?
Answer: Syphilis serology, HSV PCR from the lesion and HIV testing are important; additional STI tests depend on sexual exposure, symptoms and local epidemiology.
Q4. What are the standard first-line treatment principles for early syphilis and genital herpes?
Answer: Early syphilis is usually treated with intramuscular benzathine penicillin G; genital herpes is treated with oral antiviral medication such as acyclovir or valacyclovir.
Q5. What essential counselling should be provided to a patient diagnosed with an STI?
Answer: Explain treatment adherence, temporary sexual abstinence, condom use, appropriate partner notification and testing, confidentiality, and follow-up to confirm resolution or monitor recurrence.