Tuberculosis Flashcards
what is tuberculosis
multisystem airborne infection specifically affecting respiratory tract
what species typically causes TB
mycobacterium
TB causes caseating/non-caseating granulomatous disease
caseating with necrotic centre
describe what is commonly seen on CXR of TB
subpleural primary lesion within the lungs
Gohn focus
when would active infection occur
when T cell or macrophage response is inadequate
can either be the primary infection or can be reactivation of latent disease
describe latent disease
would a patient still experience symptoms
infection present with no disease
patient is asymptomatic
what are the symptoms of active TB
persistent productive cough, weight loss, fever, fatigue, night sweats, possible haemoptysis - also GI symptoms
MUST ask about foreign travel
what investigations are done to diagnose TB and what do they show
CXR - Gohn focus, consolidation, fibrosis and enlarged hilar lymph nodes
obtain tissue through biopsy
what is the gold standard investigation for diagnosing TB
PCR
alongside PCR, what other tests can be performed
culture - time consuming
Ziehl-Neelson
what test is used to diagnose latent TB
tuberculin skin test
when would you get a false negative tuberculin skin test
after BCG vaccine
what 4 drugs are used to treat TB
rifampicin
isoniazide
pyrazinamide
ethambutol
what is the treatment for active TB
treat with RIPE for 2 months
followed by RI for 4 months
what are side effects of rifampicin
hepatitis
red/orange urine
what are side effects of isoniazide
neuropathy
what are side effects of pyrazinamide
hepatic toxicity and decreased renal excretion
what are side effects of ethambutol
colour blindness leading to blindness
what is the treatment for latent TB
3 months on RI
6 further months on I
but depending on ability to tolerate side effects
what is miliary TB
TB that has poor management by hilar lymph nodes and has spread through the bloodstream
what does interferon gamma testing show in TB
levels of IFG released from T cells
at what stage would latent TB most likely activate
when the patient becomes immunocompromised either due to HIV or immunosuppression
