Tuberculosis Infection and Disease

A severe and forceful cough increases the likelihood of spreading tuberculosis because it releases more infectious droplets.

A positive acid-fast smear of sputum indicates a higher chance of tuberculosis transmission because it reveals the presence of the bacteria in the patient's respiratory secretions.

The primary route of transmission for Mycobacterium tuberculosis is through inhalation of airborne mucus droplet nuclei released by infected individuals.

Children exposed to high-risk adults, especially those with active TB, are at a greater risk of getting infected because they have weaker immune systems and are more vulnerable to catching the disease.

Latent tuberculosis infection (LTBI) is characterized by a positive TB skin test (TST) or interferon-gamma release assay (IGRA), but with normal chest X-ray and no symptoms of disease.

Most adults stop transmitting TB after several days to two weeks of adequate chemotherapy because the medication effectively reduces the number of bacteria in their respiratory secretions.

Young children with tuberculosis rarely infect others because their small airways and limited coughing ability lead to fewer infectious droplets being released.

The World Health Organization (WHO) estimates that the global prevalence of MDR-TB, a form of tuberculosis resistant to multiple drugs, is approximately 4% globally.

Healthcare workers caring for patients with TB, particularly those with multidrug-resistant TB, face a higher risk of getting infected due to prolonged exposure to infectious individuals.

Immunocompromised individuals, such as those with HIV/AIDS or those taking medications that weaken their immune system, are at a high risk of getting infected with TB and progressing to active TB.

Factors like the prevalence of HIV/AIDS, poverty, malnutrition, ineffective healthcare systems, and inadequate access to treatment contribute to the global TB burden.

Extensively drug-resistant tuberculosis (XDR-TB) is defined as multidrug-resistant TB (MDR-TB) plus resistance to at least one fluoroquinolone and one of the three injectable drugs, making it even harder to treat.

Around 30% to 50% of tuberculosis patients develop generalized lymphadenopathy (swollen lymph nodes throughout the body) and meningitis (inflammation of the brain and spinal cord) as complications.

A positive tuberculin skin test (TST) response can occur within 1-3 months of exposure to the TB organism, indicating that the body has developed a reaction to the bacteria.

The Mantoux tuberculin skin test (TST) is a diagnostic tool used to detect latent tuberculin infection by injecting a small amount of purified protein derivative (PPD) under the skin.

A positive acid-fast bacillus (AFB) test result indicates the presence of Mycobacterium tuberculosis in a patient's sample, suggesting an active tuberculosis infection.

The Mantoux tuberculin skin test (TST) aims to induce induration (hardening) at the injection site by triggering local vasodilation (widening of blood vessels), edema (swelling), fibrin deposition, and recruitment of inflammatory cells.

The induration, or hardened area, resulting from the Mantoux tuberculin skin test is measured by a trained person 48-72 hours after the PPD injection to determine the degree of reaction to the TB antigen.