extrinsic allergic alveolitis

Question 1

what leads to extrinsic allergic alveolitis?

Answer 1

acute allergen exposure in sensitive patients leads to type 3 hypersensitivity

chronic exposure leads to granuloma formation + obliterative bronchiolitis- type 4 hypersensitivity

Question 2

what are the causes of EAA?

Answer 2

bird fancier’s lung- proteins in bird droppings
farmers/mushroom workers
malt workers lung- aspergillus clavatus

Question 3

what are the clinical features of EAA acutely- 4-6 hours post-exposure?

Answer 3

fever, rigors, malaise
dry cough, dyspnoea
crackles- no wheeze

Question 4

what are the clinical features of EAA chronically?

Answer 4

increasing dypsnoea
weight loss
type 1 resp failure
cor pulmonale

Question 5

what do blood tests show in EAA?

Answer 5

acutely find neutrophilia + high ESR
positive serum precipitins

Question 6

what are the CXR findings in EAA?

Answer 6

upper zone reticulonodular opacification or fibrosis- honeycomb lung

bilateral hilar lymph nodes (rare)

Question 7

what is the spirometry findings in EAA?

Answer 7

restrictive
decreased transfer factor during acute attacks

Question 8

what are bronchoalveolar lavage findings in EAA?

Answer 8

high lymphocytes + mast cells

Question 9

what is the management of EAA?

Answer 9

avoid exposure
steroids- acute/long-term
compensation