A 32-year-old man from rural Maharashtra presents with a 3-week history of cough, fever, and night sweats. Chest X-ray shows a cavitary lesion in the right upper lobe with surrounding consolidation. Sputum smear microscopy is positive for acid-fast bacilli. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has microbiologically-confirmed pulmonary tuberculosis (sputum smear-positive) with classic radiological findings (cavitary lesion, upper lobe consolidation). The diagnosis is established and treatment must not be delayed. ## Why Start Anti-TB Therapy Immediately **Key Point:** Sputum smear-positive TB is infectious and requires prompt initiation of standard 4-drug therapy (RIPE: Rifampicin, Isoniazid, Pyrazinamide, Ethambutol) regardless of imaging confirmation. **High-Yield:** NTEP (National TB Elimination Programme) and WHO guidelines mandate treatment initiation within 48 hours of smear-positive diagnosis. Baseline liver function tests (LFTs) and renal function are essential because: - Isoniazid and Pyrazinamide are hepatotoxic - Ethambutol requires renal clearance assessment - Rifampicin induces hepatic enzymes **Clinical Pearl:** The presence of cavitation indicates high bacterial load and increased transmissibility—delaying therapy increases risk to household contacts and the community. ## Management Algorithm ```mermaid flowchart TD A[Sputum smear-positive TB confirmed]:::outcome --> B{Baseline investigations done?}:::decision B -->|No| C[Check LFTs, RFTs, baseline CXR]:::action C --> D[Start 4-drug regimen]:::action B -->|Yes| D D --> E[Initiate DOT in community/facility]:::action E --> F[Monitor clinical response at 2 weeks]:::outcome ``` **Tip:** Chest X-ray findings alone (cavitation, consolidation) are NOT diagnostic of TB—they are suggestive. Smear positivity + compatible imaging = confirmed TB. Imaging confirmation is NOT a prerequisite for therapy initiation when bacteriology is positive.