Model Answer
0 min readIntroduction
Tuberculosis (TB), derived from the Greek word for ‘inflammation’, remains a significant global health concern, particularly in developing countries like India. It is an infectious disease caused by the bacterium *Mycobacterium tuberculosis*. While primarily affecting the lungs (pulmonary TB), it can also affect other parts of the body (extra-pulmonary TB). According to the World Health Organization (WHO) 2023 report, India accounts for the largest share of global TB cases. Understanding the etiology, pathogenesis, diagnosis, treatment, and prevention of TB is crucial for effective control and eradication efforts.
Causative Agent and Means of Spread
The causative agent of tuberculosis is *Mycobacterium tuberculosis*, an acid-fast, rod-shaped bacterium. Less commonly, *Mycobacterium bovis* can also cause TB, usually through consumption of unpasteurized milk. The primary mode of transmission is through the air when a person with active pulmonary TB coughs, sneezes, speaks, or sings, releasing droplet nuclei containing the bacteria. These droplets can remain suspended in the air for several hours, and individuals inhaling them can become infected.
- Airborne Transmission: The most common route.
- Close Contact: Prolonged close contact with an infected individual increases risk.
- Droplet Nuclei: Small particles that can travel long distances and remain airborne.
Symptoms of Tuberculosis
Symptoms of TB vary depending on whether the person has latent TB infection or active TB disease. Latent TB infection has no symptoms. Active TB disease symptoms include:
- Pulmonary TB: Persistent cough (lasting 3 weeks or longer), coughing up blood or sputum, chest pain, weakness or fatigue, weight loss, loss of appetite, chills, fever, and night sweats.
- Extra-pulmonary TB: Symptoms depend on the organs affected. For example, TB in the lymph nodes may cause swollen lymph nodes, while TB in the spine may cause back pain.
Diagnosis of Tuberculosis
Diagnosis of TB involves a combination of medical history, physical examination, and laboratory tests:
- Tuberculin Skin Test (TST) or Interferon-Gamma Release Assay (IGRA): These tests detect latent TB infection but cannot differentiate between latent and active disease.
- Chest X-ray: Can reveal abnormalities in the lungs suggestive of TB.
- Sputum Smear Microscopy: Detects the presence of acid-fast bacilli in sputum samples.
- Sputum Culture: Confirms the diagnosis and allows for drug susceptibility testing.
- Molecular Tests (e.g., GeneXpert): Rapidly detects *M. tuberculosis* and resistance to rifampicin, a key anti-TB drug.
Treatment of Tuberculosis
TB treatment typically involves a course of antibiotics taken for 6 to 9 months. The standard treatment regimen consists of four drugs: isoniazid, rifampicin, pyrazinamide, and ethambutol (often referred to as RHEZ). Treatment is divided into two phases:
- Initial Intensive Phase (2 months): Focuses on killing the actively multiplying bacteria.
- Continuation Phase (4-7 months): Eliminates remaining bacteria and prevents relapse.
Drug-Resistant TB: The emergence of drug-resistant TB (MDR-TB and XDR-TB) poses a significant challenge. Treatment for drug-resistant TB requires longer courses of second-line drugs, which are often more toxic and less effective.
Preventive Measures of Tuberculosis
Preventive measures aim to reduce the spread of TB and prevent the development of active disease:
- BCG Vaccination: Provides some protection against severe forms of TB in children.
- Early Detection and Treatment: Identifying and treating individuals with active TB is crucial to prevent further transmission.
- Contact Tracing: Identifying and screening individuals who have been in close contact with someone with active TB.
- Infection Control Measures: Implementing measures to prevent the spread of TB in healthcare settings and other congregate settings (e.g., ventilation, masks).
- Preventive Therapy: Administering isoniazid to individuals with latent TB infection to prevent the development of active disease.
Conclusion
Tuberculosis remains a formidable public health challenge, demanding a multi-pronged approach encompassing early diagnosis, effective treatment, and robust preventive measures. Continued investment in research and development of new diagnostics, drugs, and vaccines is essential. Strengthening national TB control programs, addressing social determinants of health, and promoting awareness are crucial for achieving the goal of a TB-free world. The success of initiatives like the National Tuberculosis Elimination Programme (NTEP) in India is vital in this endeavor.
Answer Length
This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.