Extrinsic Allergic Alveolitis (Hypersensitivity Pneumonitis) Flashcards Preview

Respiratory: Interstitial lung diseases > Extrinsic Allergic Alveolitis (Hypersensitivity Pneumonitis) > Flashcards

Flashcards in Extrinsic Allergic Alveolitis (Hypersensitivity Pneumonitis) Deck (15)
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1

what is EAA?

widespread diffuse inflammatory reaction in the small airways and alveoli due to inhalation of foreign antigens, usually from animals

2

who has a decreased risk?

smokers

3

what type of hypersensitivity reaction is acute hypersensitivity pneumonitis?

Type 3 (immune complex deposition) to lymphocytic alveolitis

4

what is the Aetiology?

- Thermophilic actinomycetes hypersensitivity reaction

- farmer’s lung - caused by mouldy hay

- Malt workers lung - whiskey industry

- Bird Fancier’s lung - Avian antigens

- Mushroom farm workers and drugs - gold bleomycin, sulphasalazine

5

what are the symptoms of acute EAA?

- cough
- breathlessness
- fever
- myalgia
- classically symptoms occur several hours after exposure (flu-like illness signs)

6

what are the signs of EAA?

- with or without pyrexia
- crackles (no wheeze)
- hypoxia

7

what would a CXR show?

widespread pulmonary infiltrates

8

how is ACUTE EAA treated?

oxygen, steroid and antigen avoidance

9

what are the symptoms of chronic EAA?

progressive breathlessness and cough

10

what are the signs of chronic EAA?

may have crackles
clubbing is unusual

11

what would a CXR show for chronic EAA?

shows pulmonary fibrosis - most commonly in the upper zones

12

what would a pulmonary function test show for chronic EAA?

show restrictive defect
- low gas transfer

13

how is a diagnosis for chronic EAA made?

History of exposure, precipitins (IgG antibodies to guilty antigen)
- lung biopsy if in doubt

14

what is the treatment for chronic EAA?

- remove antigen exposure
- oral steroids if breathless (prednisolone) or low gas transfer

15

what type of hypersensitivity reaction is chronic hypersensitivity pneumonitis?

type 4