Extrinsic Allergic Alveolitis (or HP) Flashcards
1
Q
what is it
A
infiltration of small airways and alveolar walls with neutrophils followed by T lymphocytes and macrophages - leads to non-caseating granulomas
2
Q
what type hypersensitivity is it
A
type IV (or III)
3
Q
what are the different causes
A
farmers lung - mouldy hay malt workers lung - whiskey bird fanciers lung - pigeons mushroom farm workers - turning mushroom compost drugs eg gold, bleomycin, sulphasalazine
4
Q
what are acute symptoms
A
fever (pyrexia) rigors myalgia dry cough dyspnoea crackles (no wheeze) malaise
5
Q
what are chronic symptoms
A
increasing dyspnoea weight loss exertional dyspnoea type 1 resp failure cor pulmonale
6
Q
how is acute EAA diagnosed
A
blood - FBC (neutrophilia), ESR (up), ABG
CXR - upper zone consolidation
LFT - reversible restrictive, reduced gas transfer during attack
7
Q
how is chronic EAA diagnosed
A
blood - positive serum precipitants
CXR - upper zone fibrosis, honeycomb lung
LFT - persistent changes
BAL - increased lymphocytes and mast cells
8
Q
how is acute EAA treated
A
remove allergen
give O2
oral prednisolone
9
Q
how is chronic EAA treated
A
allergen avoidance
long term steroids
