Tuberculosis (TB)
Including Topics
- Introduction
- Definition
- Types Of Tuberculosis
- Causes Of Tuberculosis
- Risk Factors
- Pathophysiology Of Tuberculosis
- Signs And Symptoms Of Tuberculosis
- Diagnosis Of Tuberculosis
- Management Of Tuberculosis
Introduction
Tuberculosis (TB) is a contagious and potentially life-threatening infection primarily affecting the lungs, caused by the bacterium Mycobacterium tuberculosis. Despite being curable and preventable, TB remains a major global health challenge, particularly in low- and middle-income countries.
Definition
TB is an infectious disease caused by the Mycobacterium tuberculosis bacteria. It predominantly affects the lungs (pulmonary TB) but can also impact other organs and tissues (extrapulmonary TB).
Types of Tuberculosis
1. Pulmonary Tuberculosis : The most common form, affecting the lungs.
2. Extrapulmonary Tuberculosis : TB that affects organs other than the lungs, such as the lymph nodes, spine, or kidneys.
3. Latent Tuberculosis Infection (LTBI) : The bacteria remain in the body in an inactive state and cause no symptoms. It is not contagious but can become active.
4. Active Tuberculosis : The bacteria are active, multiply, and cause symptoms. This form is contagious.
5. Drug-resistant Tuberculosis : TB that does not respond to standard treatments due to resistance to first-line drugs.
Causes Of Tuberculosis
TB is caused by the Mycobacterium tuberculosis bacteria. The disease is transmitted through airborne particles released when a person with active TB coughs, sneezes, or talks.
Risk Factors
- Close contact with TB patients
- Living or traveling in areas with high TB prevalence
- Immunocompromised states (e.g., HIV infection, diabetes, certain cancers)
- Substance abuse (e.g., alcohol, drugs)
- Poor nutrition and living conditions
- Healthcare workers exposed to TB patients
Pathophysiology
The pathophysiology of TB involves a series of steps from initial infection to the potential spread throughout the body.
1. Inhalation of TB bacteria from an infected person.
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2. Alveolar Macrophages in the lungs engulf the bacteria.
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3. Bacterial Survival inside macrophages due to their protective cell wall.
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4. Immune Response Activation : The immune system forms granulomas to contain the infection.
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5. Latent TB : The bacteria remain contained within granulomas and do not cause symptoms.
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6. Active TB : When the immune system fails to contain the bacteria, they multiply and spread.
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7. Dissemination : TB can spread to other parts of the body via the bloodstream or lymphatic system (extrapulmonary TB).
Signs and Symptoms
- Persistent cough lasting more than three weeks
- Hemoptysis (coughing up blood)
- Chest pain
- Fever
- Night sweats
- Weight loss
- Fatigue
- Loss of appetite
Diagnosis
- Tuberculin Skin Test (TST) : Detects TB infection through skin reaction.
- Interferon-Gamma Release Assays (IGRAs) : Blood tests measuring immune response to TB bacteria.
- Chest X-ray: Identifies lung abnormalities consistent with TB.
- Sputum Culture and Microscopy : Confirms the presence of Mycobacterium tuberculosis.
- Nucleic Acid Amplification Tests (NAATs) : Rapidly detects TB DNA in clinical specimens.
- Biopsy and Imaging : For diagnosing extrapulmonary TB.
Management
Medical Management
- First-line Anti-TB Drugs :
- Isoniazid
- Rifampin
- Ethambutol
- Pyrazinamide
- Directly Observed Therapy (DOT) : Ensures adherence to the treatment regimen.
- Treatment Duration: Typically 6-9 months, depending on the type and severity of TB.
- Drug-resistant TB : Requires second-line drugs and longer treatment duration.
Surgical Management
- Resection of Infected Tissue : Removal of affected lung or other tissues in severe cases.
- Drainage of Abscesses : To control infection in extrapulmonary TB.
Nursing Management
- Infection Control : Implementing isolation protocols and using personal protective equipment (PPE).
- Medication Adherence : Monitoring and supporting patients to ensure they complete their treatment.
- Patient Education : Informing patients about TB transmission, treatment importance, and preventive measures.
- Nutritional Support : Ensuring adequate nutrition to support the immune system.
- Psychosocial Support : Providing emotional support and addressing stigma associated with TB.