A 32-year-old man from rural Maharashtra presents with a 3-month history of cough, fever, and night sweats. Chest X-ray shows right upper lobe infiltrates with cavitation. Sputum smear microscopy is positive for acid-fast bacilli (AFB). He is started on standard first-line anti-TB therapy (HRZE). On day 15 of treatment, he develops sudden-onset jaundice, right upper quadrant tenderness, and elevated transaminases (ALT 320 U/L, AST 280 U/L). Bilirubin is 4.2 mg/dL. Viral hepatitis serology is negative. What is the most appropriate next step in management?

Explanation

## Clinical Scenario Analysis This patient has **drug-induced hepatotoxicity** (likely isoniazid or rifampicin) occurring during the intensive phase of TB treatment. The key clinical features are: - Acute jaundice with markedly elevated transaminases (>300 U/L) - Negative viral serology (rules out acute viral hepatitis) - Temporal relationship to HRZE initiation ## Management of TB Drug-Induced Hepatotoxicity **Key Point:** When drug-induced liver injury (DILI) occurs during TB treatment, the approach depends on the degree of elevation and clinical severity. ### Severity Classification | Parameter | Mild | Moderate | Severe | |-----------|------|----------|--------| | ALT/AST (U/L) | 1–3× ULN | 3–5× ULN | >5× ULN or symptomatic | | Bilirubin (mg/dL) | <2 | 2–3 | >3 | | Management | Continue with monitoring | Pause hepatotoxic drugs | Discontinue all; rechallenge | This patient has **severe hepatotoxicity** (ALT 320, bilirubin 4.2) with jaundice and RUQ tenderness. ### Recommended Approach for Severe DILI 1. **Discontinue the hepatotoxic drugs** — isoniazid and rifampicin are the primary culprits 2. **Continue non-hepatotoxic agents** — pyrazinamide and ethambutol are safer in liver disease 3. **Allow LFTs to normalize** (typically 2–4 weeks) 4. **Reintroduce drugs sequentially** — start with one drug, monitor for 3–5 days, then add the next 5. **Typical rechallenge order:** Rifampicin first (most essential), then isoniazid **High-Yield:** Pyrazinamide is often implicated in DILI, but in this scenario with bilirubin >4 and symptomatic jaundice, stopping INH and RIF is standard. Ethambutol and pyrazinamide can be continued as they are less hepatotoxic. **Clinical Pearl:** Do NOT switch to second-line drugs immediately — first-line agents can usually be reintroduced once hepatotoxicity resolves. Second-line drugs are reserved for drug-resistant TB or if rechallenge fails. ## Why Option 2 Is Incorrect Discontinuing all four drugs simultaneously is overly aggressive and risks loss of TB control. Pyrazinamide and ethambutol are relatively safe and should be continued. ## Why Option 1 Is Incorrect Continuing hepatotoxic drugs when bilirubin is >4 mg/dL and the patient is jaundiced risks acute liver failure and is contraindicated. ## Why Option 4 Is Incorrect Second-line drugs should be reserved for drug-resistant TB or when first-line rechallenge fails. They are more toxic and should not be used as first-line management of DILI in drug-susceptible TB.