Tuberculosis Pathophysiology Quiz

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Questions and Answers

Which of the following health conditions is NOT identified as an immunosuppressive risk factor for developing active tuberculosis (TB)?

Diabetes mellitus

HIV infection

Asthma (correct)

Chronic kidney disease

What is the primary method of transmission for tuberculosis (TB)?

Vector-borne transmission

Direct contact with an infected individual

Inhalation of airborne droplets (correct)

Contaminated food or water

Which statement best describes the pathophysiology of tuberculosis (TB)?

It develops exclusively in individuals with no prior exposure to infections.

Infection occurs through the skin and is not linked to immune response.

It is primarily caused by respiratory allergies leading to lung inflammation.

It results from the inhalation of droplets, leading to a granuloma formation. (correct)

Which demographic factor is considered a risk factor for tuberculosis (TB)?

Substance use Signup and view all the answers

What is a key factor that increases the likelihood of latent TB progressing to active TB?

Poor access to healthcare services Signup and view all the answers

What can occur if the immune system weakens due to external factors?

The granuloma may break down, releasing bacteria. Signup and view all the answers

Which of the following is a primary mode of transmission for tuberculosis?

Airborne droplets from an infected person. Signup and view all the answers

Which demographic is at the highest risk for developing active TB?

Older adults aged 65 years and older. Signup and view all the answers

What environmental factor increases the risk of tuberculosis transmission?

Crowded living conditions. Signup and view all the answers

Which of the following individual risk factors contributes to the progression from latent TB to active TB?

Substance use and abuse. Signup and view all the answers

Which of the following groups is reported to have the highest incidence of TB?

Indigenous populations. Signup and view all the answers

Which region is considered to have high prevalence of tuberculosis, increasing the risk for recent immigrants?

Southeast Asia. Signup and view all the answers

What is a significant consequence of close, prolonged exposure to an infected individual?

Significantly increased risk of TB transmission. Signup and view all the answers

What is the primary causative agent of tuberculosis?

Mycobacterium tuberculosis Signup and view all the answers

How does Mycobacterium tuberculosis survive within macrophages?

By inhibiting lysosomal fusion Signup and view all the answers

What is the consequence of granuloma formation in TB infection?

Isolation of the bacteria from the rest of the body Signup and view all the answers

Which of the following describes latent TB infection (LTBI)?

The infection remains dormant and contained Signup and view all the answers

What type of necrosis occurs within a granuloma in TB infection?

Caseous necrosis Signup and view all the answers

Which part of the lungs is primarily affected during initial TB infection?

Upper lobes Signup and view all the answers

How long does the granuloma formation process take?

10 days Signup and view all the answers

What characteristic of Mycobacterium tuberculosis contributes to its pathogenicity?

Its thick, waxy cell wall Signup and view all the answers

Study Notes

Tuberculosis (TB)

Highly contagious infectious disease caused by Mycobacterium tuberculosis
Primarily affects the lungs, but can spread to other organs (extrapulmonary TB)
Mycobacterium tuberculosis is an acid-fast bacillus, resistant to destruction by immune cells like macrophages due to its thick, waxy cell wall.

Pathophysiology of TB

Inhalation of airborne droplets containing Mycobacterium tuberculosis leads to deposition in the upper lung lobes
Bacteria migrate to lymph nodes, phagocytosed by alveolar macrophages and neutrophils
Bacteria survive within macrophages, inhibiting lysosomal fusion; this allows for intracellular survival and infection persistence
Immune system responds by forming granulomas (tubercles) to isolate bacteria
Necrotic tissue formation (caseation necrosis) within the granuloma
Collagen deposition seals the bacteria within the granuloma (takes ~10 days)
In immunocompetent individuals, infection can remain dormant (latent TB infection)
Latent TB infection can persist lifelong

Latent TB Infection (LTBI)

Bacteria remain contained but not killed.
Can persist for the lifetime of the infected individual.

Active Tuberculosis

Weakened immune systems (e.g., due to HIV, malnutrition, aging) can cause granuloma breakdown, releasing bacteria, which can disseminate throughout lungs and other organs.

Transmission of TB

Spread via airborne droplets produced when infected individuals cough, sneeze, speak or sing.
Bacteria remain suspended in air, making transmission highly likely in crowded environments.
Prolonged exposure to an infected individual substantially increases transmission risk.

Risk Factors for TB

Environmental:*
Crowded living conditions (housing, prisons, shelters)
Homelessness
Immigration from high-prevalence regions (e.g., Southeast Asia, Africa, Western Pacific)
Individual:*
Age (25-34 and >65)
Substance use
Indigenous populations (disproportionately higher rates)
Immunosuppressive:*
HIV infection
Chronic illnesses (e.g., chronic kidney disease, diabetes, cancer)
Immunosuppressive therapy (corticosteroids, chemotherapy, anti-TNF agents)
Poor access to healthcare

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Test your knowledge on the pathophysiology of Tuberculosis (TB) and the mechanisms behind its infection and persistence. Dive into the details of Mycobacterium tuberculosis and understand how the immune system interacts with this pathogen.