Tuberculosis Flashcards
What pathogen causes tuberculosis?
Mycobacterium tuberculosis
Is infection with tuberculosis always deadly?
No. 90% of infected people’s immune systems will be able to contain and manage the infection within their bodies without symptoms or transmission risk.
How does mycobacterium tuberculosis initially avoid destruction by immune cells
It secretes substances prevent lysosomes binding with phagosomes to destroy the pathogen after phagocytosis. It then replicates within the phagocytic cell until it bursts out
How does the immune system handle tuberculosis infection?
It forms granulomas.
Destroyed macrophages release cytokines that attract helper T lymphocytes.
These helper T lymphocytes surround and boost the phagocytic ability of macrophages by secreting interferon.
This “cage” captures the mycobacterium tuberculosis and macrophages in an equilibrium of bacterial replication and phagocytic destruction with the caseous necrotic tissue in the middle (a granuloma).
What is the risk when a granuloma forms near a bronchiole?
The granuloma can erode into the bronchiole exposing the mycobacterium tuberculosis to oxygen and increasing its rate of reproduction to the point where it might not be contained by the granuloma.
What are some characteristic symptoms of tuberculosis
Blood stained sputum (Lung tuberculosis)
Severe weight loss
What are some diagnostic tests for tuberculosis?
Immune responses to mycobacterial antigens. Detects interferon release by lymphocytes in response to mycobacterial antigens
- Mantoux test
- Quantiferon test
ZN stain on samples (Not gram stain)
Sputum or lymph node sample cultures in agar or broth
PCR for mycobacterium tuberculosis DNA
X-ray to detect for caseous necrotic tissue
What is the treatment for tuberculosis
Antibiotic cocktail for 4-6 months
- Rifampicin
- Isoniazid
- Pyrazinamide
Isolation for lung tuberculosis
