Tuberculosis (TB): Symptoms, Causes & Diagnosis

Tuberculosis (TB) is caused by Mycobacterium tuberculosis. It primarily affects lungs (pulmonary TB) but can spread (extrapulmonary).

Common Symptoms (Pulmonary)

• Persistent cough >2 weeks
• Hemoptysis (coughing blood)
• Chest pain
• Fever, night sweats
• Weight loss, anorexia
• Fatigue, malaise

Extrapulmonary TB

Lymph nodes, pleura, spine (Pott's disease), brain (TB meningitis), kidneys, joints, peritoneum.

Latent TB Infection (LTBI)

Asymptomatic, non-contagious, positive IGRA/TST. Can reactivate (5–10% lifetime risk; higher if immunocompromised).

Diagnosis

• Sputum AFB smear & culture (gold standard).
• Nucleic acid amplification (GeneXpert MTB/RIF) – rapid, detects rifampin resistance.
• Imaging (CXR, CT).
• IGRA or TST for LTBI.

Treatment

Multi-drug regimen (isoniazid, rifampin, pyrazinamide, ethambutol) for 6+ months. Directly observed therapy (DOT) improves adherence. Drug-resistant TB requires longer, complex regimens.

Early diagnosis and treatment cure most TB and prevent transmission.