Tuberculosis Flashcards
What is tuberculosis?
An infectious disease usually caused by Mycobacterium Tuberculosis
Where does TB affect?
Generally affects lungs, but can also affect other parts of the body
How is M. TB spread from person to person?
Droplet infection
What happens to M. TB once inhaled?
Some bacilli remain at the site of entry, and the rest are carried to regional lymph nodes
What happens to the bacilli at the site of entry and regional lymph nodes in TB?
The bacilli multiply at both sites, with both sites collectively being referred to as the primary focus
What can happen after bacilli have divided at the primary focus in TB?
They can spread via the blood and lymphatics
What are the risk factors for TB?
- Close proximity to others infected
- Underlying immunodeficiency
- Living in endemic areas
What % of infants with TB have minimal or no symptoms?
Nearly half
What % of children with TB have minimal or no symptoms?
90%
Why do a lot of infants/children with TB have no symptoms or signs of infection?
Because a local inflammatory reaction limits the progression of the infection
What happens if the local host response fails to contain the inhaled TB?
The immune system will respond to the infection 3-6 weeks later
What symptoms occur 3-6 weeks after infection with TB if the immune system cannot contain the inhaled TB?
- Fever
- Anorexia and weight loss
- Cough
What additional problems may arise due to the inflammatory reaction in TB?
May cause bronchial obstruction with collapse and consolidation of the affected lung, and plural effusions
What kind of TB infections can become dormant?
Both symptomatic and asymptomatic
What can happen to latent TB infections?
They can subsequently become reactive and spread by lymphohaematological routes
