Tuberculosis

Tuberculosis (TB) is an infectious disease usually caused by Mycobacterium tuberculosis bacteria. TB primarily affects the lungs (pulmonary TB) but can also affect other sites (extrapulmonary TB).

Causes

  • Mycobacterium tuberculosis: A slow-growing bacterium that primarily infects lung tissue.
  • Transmission: Airborne spread through droplets expelled by someone with active pulmonary TB.

Risk Factors

  • Close contact with someone with active TB.
  • Immunosuppressive conditions (e.g., HIV/AIDS).
  • Living or traveling to areas with high TB prevalence.
  • Substance abuse.
  • Poor nutrition and living conditions.

Diagnosis

  • History:
    • Symptoms: Persistent cough (lasting more than three weeks), hemoptysis, night sweats, fever, weight loss, fatigue.
    • Risk Factors: Close contact, travel history, immunosuppression.
  • Physical Examination:
    • Lungs: Auscultation for abnormal lung sounds.
    • Lymph Nodes: Checking for enlargement.
  • Investigations:
    • Skin Test: Tuberculin skin test (Mantoux test).
    • Blood Test: Interferon-gamma release assays (IGRAs).
    • Chest X-Ray: To identify active pulmonary TB.
    • Microbiological Confirmation:
      • Nucleic acid amplification tests for M. tuberculosis.
      • Sputum smear microscopy for acid fast bacilli
      • Culture for antibiotic sensitivity testing
    • HIV Testing: Recommended due to the association between TB and HIV.

Differential Diagnosis

  • Bacterial pneumonia.
  • Bronciectasis
  • Lung cancer
  • Fungal infections of the lung
  • Sarcoidosis.

Management

  • Antibiotics: Standard treatment is a 6-month course of a combination of antibiotics (e.g. RIPE: rifampicin, isoniazid, pyrazinamide and ethambutol) for 6/12
    • Initial 2/12 includes all 4 drugs
    • Final 4/12 includes only rifampicin and isoniazid
  • Directly Observed Therapy (DOT): Ensuring compliance with treatment.
  • Monitoring: Regular follow-up, including sputum tests to monitor treatment response.
  • Infection Control: Measures to prevent spread, especially in the first few weeks of treatment.
  • Treatment of Latent TB Infection: To prevent the development of active disease.
  • Prophylaxis of close contacts: Consider to prevent the development of active disease based on risk
  • Multidrug-Resistant TB (MDR-TB): Requires longer treatment with second-line drugs.

Long-term Management

  • Continued monitoring for recurrence, especially in high-risk patients.
  • Monitoring for drug side effects, including liver toxicity.
  • Support for nutritional and psychological needs.

Prevention

  • Vaccination with Bacille Calmette-Guerin (BCG) in countries with high TB incidence.
  • Vaccination with Bacille Calmette-Guerin (BCG) in ATSI living in remote communities
  • Infection control practices in healthcare settings.
  • Screening and treatment of latent TB in high-risk populations.

In summary, TB is a potentially serious infectious disease that primarily affects the lungs but can involve other body parts. Early detection, appropriate antibiotic treatment, patient education, and public health measures are essential for managing and controlling TB.