Tuberculosis Flashcards
Define:
Granulomatous disease caused by mycobacteria tuberculosis
Primary TB - this is from initial infection and is usually pulmonary or GI (RARE)
Miliary TB - this is when the TB dissemenates
Post-primary TB - this is reactivation
Aetiology:
Mycobacteria Tuberculosis is an aerobe that stops the phagosome forming and so survives in the macrophage.
When the person is first infected it forms a granuloma
reactivates when the person’s immune system is weak such as with HIV and ageing.
The TB collonises in the upper lobes as this is where there is the most oxygen and this form cavities allowing the dissemination to occur
Risk factors:
Immunocompromised
Low CD4 count
increased ESR
high viraemia
poor nutrition
co-infection
Epidemiology:
mortality of 2 million of which 95% are in the developing world
8200 incidence in the UK (mostly in asian population)
Symptoms and signs of primary TB:
may be asymp
Fever
malaise
wheeze
Cough
erythema nodosum
phyctenular conunctivitis
Symptoms and signs of miliary TB:
Fever
weight loss
meningitis
yellow caseous tubercles
Symptoms and signs of post-primary TB:
fever
night sweats
weight loss
sputum
cough
haemoptysis
consolidation
pleuritic chest pain
fibrosis
collapse
Non-pulmonary TB symptoms and signs:
CNS - meningitis
GI - peritonitis, change in bowel habit, weight loss, subacute obstruction, ascites
Gentiourinary - epididymis, UTI, renal failure, infertility
Adrenal insufficency
Bone/joint pain - arthritis, osteomyleitis
Heart - pericardial effusion, constructive pericarditis
skin - lupus vulgaris
Investigations:
First line - CXR
Then sputum acid fast baculli smear test
–> sputum culture (gold standard) but results can take 6 weeks to come back.
FBC
Histological hallmark is caseating granulomas
In the meantime isolate the patient
Management:
RIPE
All four drugs are started at the same time:
- rifampicin
- isoniazid
- pyrasinamide
- ethambutol
RI are stopped after 6 months
PE are stopped after 2 months
sputum cultures are repeated throughout
