Tuberculosis (TB)

Tuberculosis, commonly known as TB, is a bacterial infection caused by Mycobacterium tuberculosis that primarily affects the lungs, but can also affect other parts of the body.

Causes and Risk Factors

• TB is caused by the bacterium Mycobacterium tuberculosis, which is spread through the air when an infected person coughs, sneezes, or talks.
• Risk factors for developing TB include close contact with someone who has active TB, a weakened immune system, and certain medical conditions such as HIV/AIDS, diabetes, and cancer.
• People who are malnourished, have a history of smoking, or have been infected with TB in the past are also at increased risk.

Symptoms

• Common symptoms of active TB include coughing, chest pain, and coughing up blood or mucus.
• Other symptoms may include fever, chills, night sweats, weight loss, and fatigue.
• Some people with latent TB infection (LTBI) may not exhibit any symptoms at all.

Types of Tuberculosis

• Pulmonary TB: affects the lungs and is the most common form of TB.
• Extrapulmonary TB: affects other parts of the body, such as the kidneys, spine, or brain.
• Miliary TB: a rare and severe form of TB that affects multiple parts of the body.
• Llatent TB infection (LTBI): a condition in which the bacteria are present in the body but do not cause symptoms.

Diagnosis

• TB is typically diagnosed through a combination of tests, including:
• Chest X-ray: to look for signs of lung damage or scarring.
• Sputum test: to collect and examine mucus from the lungs for TB bacteria.
• Tuberculin skin test (TST): to measure the body's immune response to TB bacteria.
• Interferon-gamma release assay (IGRA): a blood test that measures the body's immune response to TB bacteria.

Treatment

• Active TB is typically treated with a combination of antibiotics, including:
• Isoniazid (INH)
• Rifampin (RIF)
• Pyrazinamide (PZA)
• Ethambutol (EMB)
• Treatment typically lasts for 6-9 months.
• LTBI is typically treated with a single antibiotic, such as INH, for 3-9 months.

Prevention and Control

• Vaccination: the Bacillus Calmette-Guérin (BCG) vaccine is used in some countries to prevent TB.
• Infection control measures, such as wearing masks and isolating infected individuals, can help prevent the spread of TB.
• Early detection and treatment of active TB can also help prevent the spread of the disease.

Complications

• If left untreated, TB can lead to serious complications, including:
• Lung damage: scarring and damage to lung tissue.
• Spread of infection: to other parts of the body, such as the kidneys or brain.
• Respiratory failure: in severe cases, TB can cause respiratory failure, which can be life-threatening.

Epidemiology

• TB is a major public health concern worldwide, with an estimated 10 million new cases and 1.5 million deaths annually.
• The disease is most prevalent in low- and middle-income countries, particularly in Africa and Asia.