Tuberculosis Flashcards
What is TB caused by?
Mycobacterium tuberculosis
What is special about mycobacterium tuberculosis?
Rod shaped, waxy coating mean gram staining is ineffective. Acid- fastness. Require Zeihl Nielsen stain- turn bright red against blue background
How do you catch TB?
Inhaling saliva droplets- through lymphatic and blood.
What do you get in TB?
Granulomas form
What is latent TB?
Immune system encapsulates sites of infection and stops progression
Extrapulmonary TB?
Lymph nodes- cold abscess usually in neck
Pleura
CNS
Pericardium
GI
GUI
Bones and joint
Cutaneous TB
Risk factors for TB?
Known contact, immigrant from TB prevalence, immunosuppressed (HIV), homeless people drug users alcoholics,
What should be done before someone is given BCG vaccine?
Mantoux test and check for immunosuppressive and HIV
Presentation of TB?
Lymphadenopathy
Erythema no dorsum
Lethargy
Night sweats
Fever
Cough with/out haemoptysis
Weight loss
Spinal pain (Potts)
2 tests for checking persons TB status?
Mantoux test and interferon gamma release assay
What can you use to support diagnosis of TB?
CXR and cultures
What is the Mantoux test?
Inject tuberculin - bleb after 72 hours it will be read. Induration of 5mm or more is positive
What is interferon gamma release assay?
Sample of blood and mixing with TB antigen. If person previously had TB, WBC will release interferon gamma
What would CXR show for TB?
Primary- patchy consolidation, hilar lymphadenopathy and pleural effusion
Reactivated TB- patchy or modular consolidation with cavitation in upper zones
Military TB- millet seeds
How to collect cultures?
- Sputum bronchoscopy and lavage
- Mycobacterium blood cultures
Lymph node aspiration or biopsy