tuberculosis Flashcards
(47 cards)
where are majority of cases
Africa and Asia
what does it co-infect with
HIV
what are the 4 main species
- mycobacterium tuberculosis
- mycobacterium bovis
- mycobacterium africanum
- mycobacterium microti
does it stain well
no
what are they termed
acid fast bacilli
how does TB spread
via respiratory droplets
what happens once TB is inhaled into lungs
- alveolar macrophages ingest bacteria
- the bacilli then proliferate inside the macrophage and cause release of neutrophil chemoattractants and cytokines
- results in inflammatory cell infiltrate reaching lung and draining hilar lymph nodes
what does macrophage present the antigen to
T lymphocytes
what type of hypersensitivity
delayed
what does the delayed hypersensitivity result in
tissue necrosis and formation of a granuloma
what does granulomatous lesions consist of
central area of necrotic material = caseation
what happens to caseated area if they heal
become calcified
can it lie dormant
yes
what is the focus termed
Ghon focus
what does Ghon focus look like on CXR
small, calcified nodule in upper parts
what are majority of TB cases primary or reactivated
reactivated
what can cause TB to reactivate
HIV
what are factors that implicate reactivation of TB
- HIV
- chemotherapy
- diabetes
- chronic kidney disease
- malnutrition
- ageing
different sites of TB
- pulmonary
- miliary
- central venous
- lymph nodes
what should be done for suspected TB
obtain tissue or fluid microscopy
what should be done for pulmonary TB
serial sputum samples on 3 occasion
symptoms of pulmonary TB
- productive cough
- haemoptysis
- weight loss
- fevers
- sweats (end of day and night)
- hoarse voice
- severe cough
- pleuritic pain
what is seen on pulmonary TB CXR
- consolidation with or without cavitation
- pleural effusion
- thickening of mediastinum caused by hilar adenopathy
what is most common site for TB
pulmonary
