Tuberculosis (TB)
Introduction:
Tuberculosis (TB) is an infectious disease caused by the bacterium Mycobacterium tuberculosis. It primarily affects the lungs (pulmonary TB) but can also impact other parts of the body (extrapulmonary TB). TB remains a major global health issue, especially in developing countries.
Causes and Transmission:
- Causative Agent:
- Mycobacterium tuberculosis.
- Mode of Transmission:
- Airborne droplets: Spread when an infected person coughs, sneezes, or talks.
- Close contact: Prolonged exposure to an infected individual.
- Rare: Transmission through unpasteurized milk (bovine TB).
Types of TB:
- Active TB:
- The bacteria are active, causing symptoms and spreading to others.
- Latent TB:
- The bacteria remain dormant; no symptoms and not contagious.
- May become active if the immune system weakens.
Symptoms:
Pulmonary TB (Lungs):
- Persistent cough lasting more than 3 weeks.
- Coughing up blood (hemoptysis).
- Chest pain.
- Shortness of breath.
- Night sweats.
- Fever and chills.
- Unexplained weight loss.
Extrapulmonary TB:
- Affects organs like the kidneys, spine, brain, or lymph nodes.
- Spinal TB: Back pain, stiffness.
- Lymphatic TB: Swollen lymph nodes.
- TB Meningitis: Severe headaches, confusion.
Diagnosis:
- Tuberculin Skin Test (Mantoux Test):
- Injection of PPD (purified protein derivative) under the skin.
- Positive result: Red, raised bump indicates TB exposure.
- Chest X-ray: Detects lung abnormalities.
- Sputum Test: Microscopic examination and culture of coughed-up mucus.
- Blood Tests: Interferon-gamma release assays (IGRAs).
Treatment:
- Standard Treatment Regimen:
- 6-9 months of antibiotics.
- First-line drugs:
- Isoniazid (INH), Rifampin (RIF), Ethambutol (EMB), Pyrazinamide (PZA).
- Drug-Resistant TB:
- Requires second-line drugs and longer treatment.
Prevention:
- BCG Vaccine (Bacillus Calmette-Guérin):
- Given to infants in countries with high TB incidence.
- Infection Control:
- Proper ventilation in hospitals and public spaces.
- Wearing masks and practicing respiratory hygiene.
- Early Detection:
- Screening high-risk individuals (e.g., HIV patients).
Global Impact:
- Epidemiology:
- TB is one of the top 10 causes of death globally.
- High prevalence in regions like Africa, Asia, and Eastern Europe.
- Challenges:
- Drug resistance (MDR-TB, XDR-TB).
- Co-infection with HIV/AIDS complicates treatment.
Multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB) are both types of tuberculosis (TB) that are resistant to certain drugs:
MDR-TB: TB caused by bacteria that are resistant to at least two of the main TB medicines, isoniazid and rifampin. MDR-TB is difficult to treat and cure, and treatment can take months or years. The medicines used to treat MDR-TB can cause side effects.
XDR-TB: A rare type of MDR-TB that is resistant to isoniazid, rifampin, a fluoroquinolone, and at least one second-line injectable drug. XDR-TB progresses more rapidly and is more severe in people who have both XDR-TB and HIV.
Some other terms used to describe strains of TB with more extensive resistance patterns include:
- Pre-XDR-TB: MDR-TB that is resistant to either a second-line injectable drug or a fluoroquinolone
- Extremely drug-resistant TB (XXDR-TB): A term used to describe strains with more extensive resistance patterns
- Totally drug-resistant TB (TDR-TB): A term used to describe strains with more extensive resistance patterns
The spread of drug-resistant TB is a global health challenge. Some causes of the spread include: weak medical systems, incorrect treatment, and transmission in communities and facilities.
Conclusion:
Tuberculosis is a serious but treatable infectious disease. Early diagnosis, proper medication adherence, and preventive measures like vaccination are crucial for controlling its spread. Public awareness and access to healthcare are essential in reducing the global TB burden.