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