Source / episode info

• **Episode:**459
• **Title:**Divine Intervention Episode 459: The Clutch STI Podcast (for Step 1-3)
• **Published:**2023-05-25
• Source:Episode page

One-liner

This episode provides a high-yield differential diagnosis of common STIs, focusing on the distinct clinical triad (ulcer appearance, pain level, and lymphadenopathy status) for Syphilis, LGV, Granuloma Inguinale, Herpes, and Chancroid.

High-yield summary

• Syphilis: Caused by Treponema pallidum. Characterized by a classic triad: painless ulcer + painless regional lymphadenopathy (LAD). Primary chancre is the hallmark finding.
• LGV: Caused by Chlamydia trachomatis (L1–L3 serovars). Presents as a painless ulcer with painful LAD, often associated with intracellular inclusions on histology.
• Granuloma Inguinale: Caused by Klebsiella granulomatis. Characterized by a painless ulcer with NO regional lymphadenopathy. Histology shows granulation tissue and intracyloplasmic cysts.
• Herpes Simplex: Presents as painful vesicles/ulcers on an erythematous base, associated with painful LAD. Treatment requires Acyclovir; resistance necessitates Famciclovir (bypassing thymidine kinase).
• Chancroid: Caused by Haemophilus ducreyi. Characterized by a painful ulcer with painful LAD and often has a deep gray/black base.
• Syphilis Management Pearls: Penicillin is the drug of choice; Doxycycline can be used as an alternative, but penicillin remains mandatory for pregnant patients (requiring desensitization).

Learning objectives

• Differentiate the clinical presentations of major STIs (Syphilis, LGV, Granuloma Inguinale, Herpes, Chancroid).
• Identify the causative organisms and key histological findings for each STI.
• Select appropriate first-line antibiotic therapy based on the specific diagnosis and patient status (e.g., pregnancy).
• Recognize potential complications of STIs, such as neurosyphilis or leptospirosis.
• Understand the mechanism of action and resistance patterns for antiviral agents like Acyclovir.