FN: Extrinsic Allergic Alveolitis

Question 1

Definition

Answer 1

􏰀 Acute allergen exposure in sensitised pts. → T3HS
􏰀 Chronic exposure → granuloma formation and
obliterative bronchiolitis (T4HS)

Question 2

Causes

Answer 2

􏰀 Bird fancier’s lung: proteins in bird droppings
􏰀 Farmer’s / mushroom worker’s
􏰀 Malt worker’s lung: Aspergillus clavatus

Question 3

Clinical features 4-6h post-exposure

Answer 3

􏰀 Fever, rigors, malaise
􏰀 Dry cough, dyspnoea
􏰀 Crackles (no wheeze)

Question 4

Chronic clinical features

Answer 4

􏰀 Increasing dyspnoea
􏰀 Wt. loss
􏰀 T1 respiratory failure
􏰀 Cor pulmonale

Question 5

Investigation bloods show

Answer 5

􏰁 Acute: neutrophilia, ↑ESR

􏰁 +ve se precipitins

Question 6

Ix CXR

Answer 6

􏰁 Upper zone reticulonodular opacification or fibrosis → honeycomb lung
􏰁 BHL (rare)

Question 7

Ix Spirometry

Answer 7

􏰁 Restrictive defect

􏰁 ↓ transfer factor during acute attacks

Question 8

Ix BAL

Answer 8

􏰁 ↑ lymphocytes and mast cells

Question 9

Mx

Answer 9

􏰀 Avoid exposure
􏰀 Steroids: acute / long-term
􏰀 Compensation may be payable