TB Flashcards
What bacterium is responsible for TB?
Mycobacterium tuberculosis
True or False:
Mycobacterium tuberculosis is an obligate aerobe
True
What is used to stain for mycobacterium tuberculosis?
Ziehl-Neelson stain
True or False:
Mycobacterium tuberculosis is one of the fastest bacteria to grow so are very easy to culture
False
Take a long time to culture
Generation time 15-20h
How is TB spread?
Respiratory droplets - coughing, sneezing etc
Outline the pathogenesis of TB
1) Inhaled infectious droplets - carried to lungs
2) Engulfed by alveolar macrophages - local lymph nodes (either progresses to primary active disease or contains)
3) Latent infection - can reactivate as post primary TB
Why are HIV patients at risk of TB?
Behave as intracellular organisms so T cells are important
Are TST or IFN gamma tests usually positive or negative in a patient with TB?
Positive - sensitised cells to TB antigens
What are some risk factors for reactivation of TB?
- Infection with HIV
- Substance abuse
- Prolonged corticosteroids
- TNF-a antagonists
- Organ transplant
- Haematological maligancy
- Diabetes
What kind of granulomas do patients with TB present with?
Caseating granulomas
What are risk factors for TB?
Non UK born HIV Homeless Drug users Prisoners Close contacts
What are some symptoms of pulmonary TB?
Fever Night sweats Weight loss Malaise Cough Haemoptysis Breathlessness if pleural effusion
How do you investigate pulmonary TB?
Chest X Ray
Sputum - 3 early morning samples
Induced sputum
Bronchoscopy
What are the first line TB drugs?
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
What must be given along with INAH to prevent peripheral nerve damage?
Pyradoxine (Vit B6)
