Respiratory · Year 1 · from Respiratory
Case 2: Pulmonary Tuberculosis with Cavitary Disease
Case Presentation
A 45-year-old man originally from India, now living in the US for 2 years, presents with a 3-month history of persistent cough productive of blood-tinged sputum, unintentional weight loss of 15 pounds, night sweats that soak his bedclothes, and low-grade fevers. He works in a homeless shelter. On examination, he appears cachectic. Vital signs show temperature 38.2C, heart rate 88 bpm, and oxygen saturation 95% on room air. Chest examination reveals decreased breath sounds and crackles in the right upper lobe.
Chest X-ray shows a right upper lobe cavitary lesion with surrounding infiltrate and no hilar lymphadenopathy. This pattern of apical cavitary disease is classic for reactivation tuberculosis, in contrast to primary TB which typically affects the middle/lower lobes with prominent hilar adenopathy.
Three sputum samples are collected for acid-fast bacilli (AFB) smear and culture. AFB smear is positive (3+), indicating high bacillary load and high infectivity. GeneXpert MTB/RIF (nucleic acid amplification test) confirms Mycobacterium tuberculosis without rifampin resistance, providing rapid results within hours while awaiting culture (which takes weeks).
The pathophysiology of reactivation TB involves breakdown of previously contained granulomas, often in the oxygen-rich lung apices where M. tuberculosis thrives. The cavities form from caseous necrosis liquefying and draining into airways, creating an oxygen-rich environment for massive bacterial proliferation. Cavitary disease is highly infectious.
The patient is placed in airborne isolation (negative-pressure room, N95 respirators for healthcare workers). He is started on RIPE therapy: Rifampin, Isoniazid, Pyrazinamide, and Ethambutol for 2 months (intensive phase), followed by Rifampin and Isoniazid for 4 months (continuation phase). Pyridoxine (vitamin B6) is given to prevent isoniazid-induced peripheral neuropathy. Public health is notified for contact investigation. After three consecutive negative AFB smears and clinical improvement, he is discharged on directly observed therapy (DOT) to ensure adherence.
Key Learning Points
- Reactivation TB classically presents with upper lobe cavitary disease, constitutional symptoms (fever, night sweats, weight loss)
- Primary TB differs: middle/lower lobe disease with hilar lymphadenopathy in recently infected patients
- Cavitary disease indicates high bacillary load and high infectivity - requires airborne isolation
- Standard treatment: RIPE (Rifampin, Isoniazid, Pyrazinamide, Ethambutol) for 2 months, then RI for 4 months
- GeneXpert provides rapid TB confirmation and rifampin resistance detection