hypersensitivity pneumonitis Flashcards
what is hypersensitivity pneumonitis? What is it also known as?
Hypersensitivity reaction to organic molecules/antigenic materials
- a.k.a. farmers lung/bird fanciers lung
What is the pathophysiology of hypersensitivity pneumonitis?
Immune complex mediated combined type lll and type lV hypersensitivity reaction
Why is it associated with upper zones?
the clearance is as efficient in apices compared to lung bases
what are 3 risk factors of hypersensitivity pneumonitis?
bk, f, be
- Bird keeping
- farming
- bioaerosols exposure
What are 5 presentations of acute hypersensitivity pneumonitis?
A, CTW, D, F, M
- allergen exposure
- crackles, tachypnoea, wheeze
- dry cough
- fever
- myalgia (muscle pain)
what are 2 presentations of chronic hypersensitivity pneumonitis?
- allergen exposure
- more than 6 weeks of insidious symptoms
e.g. cough, dyspnoea, malaise, wheeze
what 5 investigations are used for in hypersensitivity pneumonitis? what do they show?
C, C, D, L, S
CT scan
- chronic changes e.g. honeycomb and ground, glass appearance
chest x-ray
- chronic fibrosis changes
detailed exposure history
lymphocytes bronchoscopy
spirometry
- restrictive pattern
What 3 treatments are used for hypersensitivity pneumonitis?
1 general, 1 acute, 1 chronic
Avoid triggers
e.g. bird keeping, farming
acute -> glucocorticoids
chronic -> glucocorticoids +/- immuno suppression