TUBERCULOSIS

**TUBERCULOSIS **

Definition : Tuberculosis is a chronic infectious disease produced by Mycobacterium tuberculosis

Types : Pulmonary TB – disease confined to the lungs; Extrapulmonary TB – disease in other organs such as lymph nodes, pleura, bone, genitourinary tract, meninges

Pathology : Inhaled bacilli are engulfed by alveolar macrophages → intracellular multiplication → cell‑mediated immunity is activated → epithelioid cell granulomas form → central caseous necrosis develops → granuloma may heal with fibrosis or cavitate → bacilli can spread through airways or bloodstream

Clinical features : Persistent cough lasting more than two weeks, sputum production, occasional hemoptysis, pleuritic chest pain, low‑grade fever, night sweats, weight loss, anorexia, fatigue – these are the typical pulmonary manifestations; Extrapulmonary manifestations depend on the organ involved (e.g., cervical lymphadenopathy, pleural effusion, abdominal pain, back pain in spinal TB, meningitic signs, dysuria in genitourinary TB)

Diagnosis : Clinical suspicion based on symptoms and risk factors → chest X‑ray shows infiltrates, cavitation, hilar lymphadenopathy → sputum smear microscopy for acid‑fast bacilli → sputum culture on solid or liquid media for definitive identification → nucleic‑acid amplification test (PCR/ GeneXpert) for rapid detection → tuberculin skin test or interferon‑γ release assay for latent infection → CT or MRI for extrapulmonary sites as indicated → routine blood tests (CBC, ESR, CRP) support inflammatory picture

Investigations : Sputum AFB smear, sputum culture, GeneXpert/ PCR, chest radiograph, CT/MRI for specific sites, CBC, ESR, CRP

Complications : Pulmonary – massive hemoptysis, bronchiectasis, secondary bacterial pneumonia, respiratory failure; Extrapulmonary – spinal deformity (Pott’s disease), tubercular meningitis, renal failure, pericardial tamponade

Management / Treatment : First‑line regimen – isoniazid + rifampicin + pyrazinamide + ethambutol for 2 months → isoniazid + rifampicin for additional 4 months (total 6 months) → administered under Directly Observed Treatment, Short‑Course (DOTS) to ensure compliance → monitor liver enzymes and visual acuity during therapy → drug‑resistant cases managed with second‑line agents (fluoroquinolones, injectable aminoglycosides) according to sensitivity results

Prevention : BCG vaccination at birth → strict infection‑control measures in health‑care settings → contact tracing and prophylactic isoniazid for persons with latent infection