Pulmonary Tuberculosis

A collection of flashcards detailing the key concepts, terminologies, and historical aspects related to pulmonary tuberculosis.

Pulmonary Tuberculosis

An ancient infection caused by the bacterium Mycobacterium tuberculosis, affecting humans throughout history.

Mycobacterium tuberculosis

The bacterium that causes pulmonary tuberculosis, discovered by Robert Koch in 1882.

Acid-fast

A characteristic of Mycobacterium tuberculosis that allows it to resist decolorization by acids during laboratory testing.

Granuloma

A focal area of inflammation in lung tissue formed during the immune response to tuberculosis bacteria.

Caseous necrosis

A type of tissue necrosis associated with tuberculosis characterized by a cheese-like appearance.

R0

The basic reproduction number indicating the average number of persons infected by a single infected individual; in tuberculosis, R0 = 15.

Tuberculin skin test

A diagnostic skin test using purified protein derivative (PPD) to identify latent tuberculosis infection.

BCG vaccine

A live attenuated vaccine derived from Mycobacterium bovis, used to prevent tuberculosis, especially in children.

Interferon Gamma Release Assay (IGRA)

A blood test measuring immune response to specific tuberculosis antigens; can be used instead of the tuberculin skin test.

Delays-type hypersensitivity (DTH)

An immune response that can lead to tissue necrosis during the infection process of tuberculosis.

Multidrug-resistant tuberculosis (MDR-TB)

A strain of tuberculosis resistant to at least isoniazid and rifampin, requiring extensive chemotherapy.

Pulmonary Tuberculosis

A chronic, infectious respiratory disease caused by the bacterium Mycobacterium tuberculosis, known to have afflicted humans for millennia, leading to significant global morbidity and mortality.

Mycobacterium tuberculosis

The specific bacterial species, often referred to as Koch's bacillus, responsible for causing pulmonary tuberculosis. It was famously discovered and identified by Robert Koch in 1882, marking a pivotal moment in understanding the disease.

Acid-fast

A crucial microscopic property of Mycobacterium tuberculosis, where its cell wall, rich in mycolic acid, resists decolorization by acid-alcohol after staining. This characteristic is vital for its identification in laboratory diagnostic tests, such as the Ziehl-Neelsen stain.

Granuloma

A highly organized and compact cluster of immune cells (primarily macrophages) and other inflammatory cells that form a focal lesion in the lung tissue. This structure is the primary host defense mechanism to contain Mycobacterium tuberculosis within the body, preventing its spread, but also allowing latent infection to persist.

Caseous necrosis

A distinctive form of cell death commonly observed in granulomas associated with tuberculosis. It results in a soft, crumbly, whitish-yellow core that resembles cheese, indicative of the destruction of tissue and immune cells by the infection. The presence of caseous necrosis is a pathological hallmark of active tuberculosis.

R0

The basic reproduction number ($R<em>0$), a fundamental epidemiological parameter that quantifies the average number of new infections generated by one infected individual in a susceptible population. For tuberculosis, an estimated $R</em>0 = 15$ indicates its significant transmissibility, though this can vary by context.

Tuberculin skin test

A diagnostic procedure, also known as the Mantoux test, used to screen for latent tuberculosis infection. It involves an intradermal injection of Purified Protein Derivative (PPD) from Mycobacterium tuberculosis; a positive reaction (induration) indicates prior exposure or infection due to a delayed-type hypersensitivity response.

BCG vaccine

The Bacillus Calmette-Guérin vaccine, a live attenuated (weakened) vaccine derived from Mycobacterium bovis. It is widely used in countries with high tuberculosis prevalence, particularly to protect infants and young children against severe forms of TB, such as meningeal tuberculosis and disseminated disease.

Interferon Gamma Release Assay (IGRA)

A modern blood test that detects latent or active tuberculosis infection by measuring the T-cell immune response to specific Mycobacterium tuberculosis antigens (e.g., ESAT-6, CFP-10). IGRAs offer advantages over the tuberculin skin test, such as being unaffected by prior BCG vaccination and requiring only one patient visit.

Delays-type hypersensitivity (DTH)

A cell-mediated immune reaction, typically peaking 24-72 hours after antigen exposure, which plays a critical dual role in tuberculosis. While it is essential for the formation of granulomas and containing the infection, an excessive or misdirected DTH response can also contribute significantly to the tissue damage and destructive lung pathology characteristic of active tuberculosis.

Multidrug-resistant tuberculosis (MDR-TB)

A particularly challenging form of tuberculosis characterized by resistance to at least the two most potent first-line anti-TB drugs: isoniazid and rifampin. Treating MDR-TB requires longer and more complex chemotherapy regimens with second-line drugs, often leading to poorer patient outcomes and significant public health concerns.