Microbiology - TB + Mycobacteria Flashcards
What is a Gohn focus?
- A tuberculous caseating granuloma (tuberculoma) seen in upper/mid zones
- Pulmonary TB
What is a Gohn comlpex?
- Gohn focus
- Lymphadenopathy
What is a RF for symptomatic primary TB infection?
Immunocompromised
What is the process of getting TB?
- Exposure
- Can become infected or non-infected
- IF infected can have primary TB symptoms, leading to latent TB, or just have latent TB
- Latent TB is asymptomatic, but can have Gohn focus + granuloma
- Can have no reactivation (asymptomatic) or reactivation (symptomatic)
What is a classic lesion of TB?
Caseating granuloma
What are some RFs of developing TB?
- Travel (South Asia/Eastern Europe)
- HIV +ve
- Homeless
- IVDU
- Contact
What are some general symptoms of TB?
FLAWS
What are some respiratory symptoms of TB?
- Haemoptysis
- Cough
What are some less common presentations of TB (seen in immunocompromised)?
- Subacute meningitis
- Pott’s Disease (spinal)
- Miliary TB
What are some symptoms of subacute meningitis and how is it caused from TB?
- TB infiltration into brain
- Headaches
- Personality changes
- Meningism
- Confusion
What are some symptoms of Pott’s disease (secondary to TB)?
- Back pain
- Vertebral destruction
- Iliopsoas abscess
What is a sign of miliary TB (seen on CXR)?
Disseminated haematogenous spread
- Miliary seed appearance
What are some investigations used to diagnose TB and the results?
- CXR: Upper lobe cavitation
- Sputum samples (X3): Ziehl-Neelson stain (culture on Lowenstein-Jensen medium for 6/52) shows acid-fast bacilli
- Tuberculin skin etsts (Mantoux/Heaf) - shows exposure (inc. BCG)
- IGRA (Elispot/Quantiferon) - shows exposure (exc. BCG)
What is the gold standard investigation for diagnosing TB?
Ziehl-Neelson stain
What is the first-line treatment for TB?
RIPE
- Rifampicin
- Isonazid
- Pyrazinamide
- Ethambutol
All 4 for 2 months, first two for 4 months
