Tuberculosis (TB)
- Notifiable (within 3/7)disease
- airborne spread by bacterium Mycobacterium tuberculosis.
- usually only lung infection, but kidney, spine, and brain can be affected.
- Not everyone infected becomes sick.
- Latent TB - asymptomatic but test +ve. Can become active if immune system compromised. 1:10 will become active at some point
- active TB - symptomatic and test +ve
Immunity
- bacille Calmette-Guérin (BCG) vaccine - does not prevent primary infection or prevent reactivation of pulmonary TB. It does seem to protect against meningitis and disseminated TB in children
- Tests, but which do not distinguish between Latent and Active TB
- Mantoux test (TB skin test) - injection of tuberculin under skin and skin reaction interpreted 48-72/24 later
- interferon-gamma release assay (IGRA) - blood test preferred if patient has previously had BCG vaccine
Management
- isoniazid and rifampicin for 6/12 (Latent TB - 3/12 combination, or isoniazid alone for 6/12)
- pyrazinamide and ethambutol for 1st 2/12 of the same 6/12 treatment period
- usually not infectious after 2/52 of Rx
- steroids occasionally if TB elsewhere
- Multidrug resistant TB - antibiotics for >9/12
- Latent TB - recommendations vary but <65y and no C/I should be Rx.
Presentation
- prolonged cough, sometimes productive or with haemoptysis
- chest pain
- LOW, loss of apetite
- fevers, chills, night sweats
- signs of other organ problems depending on site - eg localised pain, confusion (meningitis, encephalitis)
Countries with high TB rates
- Africa – particularly sub-Saharan Africa (all the African countries south of the Sahara desert) and west Africa
- south Asia – including India, Pakistan, Indonesia and Bangladesh
- Russia
- China
- South America
- the western Pacific region (to the west of the Pacific Ocean) – including Vietnam, Cambodia and the Philippines