Tuberculosis Flashcards
Pathophysiology
Macrophages migrate to regional lymph nodes
- lung lesion plus lymph nodes referred to Ghon complex
Leads to formation of granuloma (epithelioid histiocytes)
Presence of caseous necrosis in the middle
Mediated by type 4 hypersensitivity reaction
In healthy individuals may be contained, in immunocompromised disseminated TB may occur
Risk factors
Having lived in Asia, Latin America, Eastern Europe, Africa for years
Exposure to infectious TB case
People infected with HIV (20-30x more likely to develop TB)
Immunocompromised
Silicosis
Apical fibrosis
Most common site for TB infection
Lungs as plenty of oxygen
Extrapulmonary TB
Lymph nodes
Pleura
CNS
Pericardium
GI system
GU system
Bones and joints
Cutaneous TB affecting the skin
BCG vaccine
Intradermal live attentuated TB
Less effective at protecting against pulmonary TB
Tested with Mantoux test before given vaccine
Presentation
Lethargy
Fever or night sweats
Weight loss
Cough (haemoptysis)
Lymphadenopathy
Erythema nodosum
Spinal pain (Pott’s disease of the spine)
False negative Mantoux tests
Miliary TB
Sarcoidosis
HIV
Lymphoma
Very young age <6 months
Diagnosis of active TB
Chest xray
Sputum smear (3 specimens need, Ziehl-Neelson stain)
Sputum culture cold standard (can take 1-3 weeks)
NAAT (24-48h, more sensitive than smear but less than culture)
Initial management
Rifampicin
Isoniazid
Pyrazinamide
Ethambutol
First 2 months
Continuation phase treatment
Rifampicin
Isoniazid
Another 4 months
Treatment of latent TB
3 months isoniazid (with pyridozine) and rifampicin
OR
6 months isoniazid (with pyroxidine)
Treatment of meningeal TB
Treated for prolonged period (at least 12 months)
Addition of steroids
Rifampicin side effects
Potent liver enzyme inducer
Hepatitis
Orange secretions
Flu-like symptoms
Isoniazid side effects
Peripheral neuropathy (prevent with pyroxidine (B6))
Hepatitis
Agranulocytosis
Liver enzyme inhibitor
Pyrazinamide side effects
Hyperuricaemia causing gout
Arthralgia
Myalgia
Hepatitis
