Resp 8 - Tuberculosis Flashcards
Describe Mycobacterium tuberculosis:
- Obligate aerobe
- Non-motile
- Rod-shaped
- Slow growing
- Acid+Alcohol fast
What stain would you use to test for Mycobacterium tuberculosis?
- Ziehl-Nielson stain
- Auramine stain
How is TB transmitted?
Aerosol droplets = sneezing/coughing/talking
Describe the granuloma formed in Tuberculosis:
Infected macrophages + Langhans giant cells surrounded by foamy macrophages, surrounded by T lymphocytes in a fibrous cuff, with central caseation.
In what percentage of people with latent TB, does the infection go on to cause post-primary TB?
5%
What are the risk factors for post-primary TB?
Immunocompromised:
- HIV+
- IVDU
- Organ transplant
- Low body weight
- Haematological malignancy
- Severe kidney disease
- Diabetes mellitus
- Prolonged corticosteroid use
Give the symptoms of TB:
- Fever
- Night sweats
- Severe cough
- Weight loss/anorexia
- Tiredness
- Haemoptysis
- Breathlessness (if pleural effusion)
Describe the CXR findings of a patient with TB:
- Ill-defined patchy consolidation +/- central cavity formation (appears darker)
- Usually in apex of lung
- May see fibrosis (forms during healing)
- Pleural effusion may be present
What is Scrofula?
Cervical lymph node TB infection
What is Pott’s disease?
Spinal TB, usually thoracolumbar
= progressive bone destruction
How can you induce sputum production?
Give patient nebulised hypertonic saline solution, which liquefies secretions and promotes coughing
What could cause a false positive Mantoux test?
BCG vaccination
What could cause a false negative Mantoux test?
Immunocompromisation
ie HIV+, IVDU etc
What are the main, 1st line drugs used to treat TB?
1) Rifampicin
2) Isoniazid
3) Pyrazinamide
4) Ethambutol
Which anti-TB drug causes orange secretions?
Rifampicin
Which anti-TB drug’s are toxic to hepatocytes?
- Isoniazid
- Pyrazinamide
Which anti-TB drug causes visual disturbances?
Ethambutol
Which vitamin is given as a supplement during an antibiotic course for TB?
Vitamin D = accelerates recovery
What are the risk factors for MDR TB?
- Previous TB prescription
- HIV+
- Known contact with MDR TB
What type of TB does the BCG mainly vaccinate against?
- TB meningitis
- Miliary TB
Who is at particular risk of developing TB in the UK?
- HIV+
- IVDU’s
- Overcrowded areas: Prisons/homeless shelters/nursing homes
- People exposed to high-risk people: healthcare workers, family
