A 26-year-old man has a low-grade fever and left-sided pleural effusion. Pleural fluid analysis shows a lymphocytic exudate with 70 U/L adenosine deaminase (ADA). Chest radiograph shows no parenchymal lesion. What is the most appropriate next step?

• A Start empirical corticosteroids for rheumatoid pleurisy
• B Discharge with observation, as the value is nondiagnostic
• C Treat as a parapneumonic effusion with antibiotics and drainage
• D Begin antitubercular therapy for tuberculous pleuritis ✓

Explanation

An ADA level above 40 U/L in a lymphocytic exudative effusion has sensitivity and specificity above 90 percent for tuberculous pleuritis in Indian practice, so antitubercular therapy is appropriate without waiting for closed pleural biopsy. Values below 35 U/L make TB unlikely and demand an alternative diagnosis. D purely lymphocytic exudate with high ADA does not fit parapneumonic or rheumatoid effusions, which are neutrophil-predominant or associated with systemic features respectively.

Reference: Harrison's Principles of Internal Medicine, 21st ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.