Tuberculosis Flashcards
What is TB caused by?
The bacteria mycobacterium tuberculosis
Describe the characteristics of the causative agent of TB?
Gram positive bacillus
Acid fast
Slow growing
What type of hypersensitivity does TB cause?
Type IV
How is TB transmitted?
Aerosol route
Some who come into contact with TB will not contract the disease, some will and some will have latent TB and be affected later in life
What is a Ghon complex?
The combination of a Ghon focus (small lung lesion composed of macrophages) and hilar lymph nodes
What is the pathophysiology of primary TB
- Primary infection of the lungs
- Ghon focus and Ghon complex forms
- Granuloma forms
- Caseous necrosis occurs
What is a granuloma?
A collection of epithelioid histiocytes
What is the difference between primary and secondary TB?
Primary is when you get it for the first time
Secondary is when an initial infection is reactivated
Where does secondary TB usually occur?
Apex of lungs
May spread locally or to distant sites
What causes secondary TB?
Immunosuppression (drugs like steroids, HIV)
Malnutrition
Where outside of the lungs can TB affect?
CNS
Vertebral bodies (Pott’s disease)
Renal
GI tract
What ages tend to present with TB?
Very young children, young adults and the elderly
What are the high risk groups for TB?
Deprived areas
Immigrants or foreign travel from Asia, Latin America, Eastern Europe or Africa
Immunosuppressed
Silicosis and apical fibrosis
What is the majority of TB disease?
Re-activated disease in individuals previously entering the country with latent TB infection
What are the symptoms ofTB?
Persistent productive cough Haemoptysis Pleuritic chest pain Hoarseness Upper zone crackles Night sweats Fever Weight loss
