Tuberculosis is an infectious disease caused by the bacterium Mycobacterium tuberculosis. It mainly affects the lungs (pulmonary tuberculosis) but can also spread to other parts of the body such as the brain, kidneys, spine, lymph nodes, and bones. TB spreads from person to person through the air, usually when a person with active pulmonary TB coughs, sneezes, or speaks, releasing tiny droplets containing the bacteria.

Tuberculosis : Causes, Symptoms, Diagnosis, Treatment, and Prevention

Tuberculosis, commonly known as TB, is one of the most ancient yet persistent infectious diseases affecting humanity. Despite major medical advancements, TB remains a serious global health concern, particularly in developing countries. According to the World Health Organization (WHO), nearly 10 million people fall ill with TB each year, and around 1.3 million die due to this disease.

TB is classified into two forms:

1. Latent TB infection – The bacteria remain inactive in the body, and the person shows no symptoms. However, latent TB can turn into active TB if the immune system weakens.
2. Active TB disease – The bacteria multiply, causing noticeable symptoms and making the person contagious.

Causes of Tuberculosis

1. The primary cause of TB is infection with Mycobacterium tuberculosis. However, not everyone exposed to the bacteria develops the disease. The chances of developing active TB depend on:
2. Weak immune system (HIV, diabetes, cancer, malnutrition)
3. Close contact with a TB patient
4. Living in crowded or poorly ventilated environments
5. Substance abuse (alcohol, drugs, smoking)
6. Long-term use of corticosteroids or immunosuppressants
7. Other species of mycobacteria, such as Mycobacterium bovis and Mycobacterium africanum, can also cause TB but are less common.

Types of Tuberculosis

Tuberculosis is classified based on the organ system it affects:

1. Pulmonary Tuberculosis (Lung TB)

• The most common type.

• Symptoms include cough, chest pain, and blood in sputum.

2. Extrapulmonary Tuberculosis (Outside the lungs)

• TB of lymph nodes, bones, kidneys, or brain.

• Common in people with weak immunity.

3. Miliary Tuberculosis

• A rare but severe form where bacteria spread throughout the body via the bloodstream.

4. Drug-Resistant Tuberculosis (DR-TB)

• Caused when TB bacteria become resistant to standard anti-TB drugs.

• Includes MDR-TB (multi-drug-resistant) and XDR-TB (extensively drug-resistant).

Symptoms of Tuberculosis

Symptoms vary depending on the type of TB, but the most common signs of pulmonary TB include:

1. Persistent cough lasting more than 2 weeks
2. Coughing up blood or sputum
3. Chest pain or discomfort while breathing
4. Unexplained weight loss
5. Fever and night sweats
6. Fatigue and weakness
7. Loss of appetite
8. In extrapulmonary TB, symptoms depend on the affected organ:
9. Lymph node TB – swelling in the neck or armpit
10. Spinal TB – back pain, stiffness, possible paralysis
11. Kidney TB – blood in urine, flank pain
12. Brain TB (TB meningitis) – severe headache, confusion, seizures

How Tuberculosis Spreads

1. TB spreads through airborne droplets. When an infected person coughs, sneezes, or talks, tiny particles carrying the bacteria can remain suspended in the air for hours.
2. Inhaling these droplets may lead to infection.
3. TB is not spread by touching, sharing utensils, food, or water.
4. The risk of transmission is higher in crowded, poorly ventilated places such as slums, prisons, or refugee camps.

Risk Factors for Tuberculosis

1. Certain factors increase the risk of TB infection or developing active disease:
2. HIV infection – TB is the leading cause of death in HIV patients.
3. Diabetes mellitus – weakens immunity.
4. Malnutrition – poor diet reduces body’s defense.
5. Alcoholism and drug abuse – weakens lungs and immune system.
6. Smoking – damages lungs, making them vulnerable.
7. Chronic kidney disease or cancer treatment.
8. Living in TB-endemic regions.

Diagnosis of Tuberculosis

Early diagnosis is crucial to prevent TB spread and complications. Common diagnostic methods include:

1. Medical history and physical examination

• Doctor checks symptoms, risk factors, and past exposure.

2. Laboratory tests

• Sputum smear microscopy – detecting TB bacteria in sputum under a microscope.

• Sputum culture test – more accurate, confirms drug resistance.

3. Tuberculin Skin Test (TST) or Mantoux Test

• A small amount of TB protein is injected into the skin; swelling indicates infection.

4. Blood tests (Interferon-Gamma Release Assays – IGRAs)

• Useful for detecting latent TB infection.

5. Imaging tests

• Chest X-ray or CT scan – shows lung damage or TB lesions.

6. Biopsy and specialized tests

• For extrapulmonary TB, tissue samples may be tested.

Treatment of Tuberculosis

TB is curable with proper and complete treatment. The standard treatment includes:

1. First-Line Anti-TB Drugs

• Isoniazid (INH)

• Rifampicin (RIF)

• Pyrazinamide (PZA)

• Ethambutol (EMB)

These drugs are given in combination for 6 months under the Directly Observed Treatment, Short-course (DOTS) strategy recommended by WHO.

2. Drug-Resistant TB Treatment

• Requires second-line drugs such as fluoroquinolones and injectable antibiotics.

• Treatment may last 18–24 months.

3. Supportive Treatment

• Adequate nutrition, rest, and management of co-existing conditions like HIV and diabetes.

• Important Note: Incomplete or irregular treatment leads to drug resistance, making TB harder to cure.

Complications of Tuberculosis

1. If left untreated or poorly managed, TB can cause:
2. Lung damage leading to respiratory failure
3. Spinal deformities and paralysis
4. Kidney or liver failure
5. TB meningitis causing brain damage
6. Death in severe cases

Prevention of Tuberculosis

TB prevention focuses on breaking the chain of transmission:

1. Vaccination (BCG Vaccine)

• Given to infants in many countries to prevent severe forms of TB.

2. Early Detection and Treatment

• Prompt diagnosis and treatment of TB patients reduce spread.

3. Infection Control Measures

• Improving ventilation in homes, hospitals, and public places.

• Wearing masks in high-risk areas.

4. Protecting High-Risk Groups

• Preventive therapy for people with latent TB, especially HIV-positive individuals.

5. Healthy Lifestyle

• Good nutrition, exercise, and avoiding smoking or alcohol strengthen immunity.

Global Burden of Tuberculosis

• High-burden countries include India, China, Indonesia, Pakistan, Nigeria, and South Africa.
• WHO’s End TB Strategy aims to reduce TB deaths by 90% by 2035.
• Despite progress, challenges remain due to drug resistance, poverty, and lack of awareness.

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Tuberculosis and India

• India carries the largest burden of TB in the world, with nearly one-fourth of global TB cases.
• The Indian government runs the National TB Elimination Programme (NTEP).
• Free diagnostic and treatment services are available in government hospitals.
• Awareness campaigns focus on early testing, complete treatment, and stigma reduction.

Living with Tuberculosis

• A TB diagnosis can be stressful, but with proper treatment and support, patients can recover fully. Some key tips:
• Take medicines regularly as prescribed.
• Do not stop treatment midway, even if symptoms improve.
• Eat a nutritious diet rich in protein, vitamins, and minerals.
• Avoid alcohol and smoking to protect the lungs.
• Isolate temporarily if contagious, to protect family and friends.

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Myths and Facts about Tuberculosis

❌ Myth: TB spreads through food and utensils.
✅ Fact: TB spreads only through air, not by sharing food or touching.

❌ Myth: Only poor people get TB.
✅ Fact: Anyone can get TB, though risk is higher in low-income groups.

❌ Myth: TB cannot be cured.
✅ Fact: TB is fully curable with proper treatment.

❌ Myth: Once cured, TB never comes back.
✅ Fact: TB can relapse, especially if immunity is weak or treatment was incomplete.