Hypersensitivity Pneumonitis

Question 1

Hypersensitivity Pneumonitis

Answer 1

Inhalation of allergens provoke hypersensitivity reaction => IgG & immune complexes deposited in walls of alveoli & bronchioles causing inflammation.

Question 2

Type of Hypersensitivity reaction

Answer 2

Type III or Type IV

Question 3

How long does it take for symptoms to appear in acute hypersensitivity Pneumonitis?

Answer 3

4-6 hours after acute exposure

Question 4

Chronic inflammatory disease

Answer 4

Repeated low dose antigen exposure over time (years) resulting in granuloma formation & obstructive bronchitis in small airways & interstitium.

Question 5

Cause of farmers lung

Answer 5

Spores from hay

Question 6

Cause of pigeon fanciers lung

Answer 6

Avian proteins in bird poo

Question 7

Cause of malt workers lung

Answer 7

Aspergillus from malt

Question 8

Causes

Answer 8

Spores, proteins, aspergillus, drugs & 30% idiopathic.

Question 9

Symptoms of acute HP

Answer 9

Dry cough, dyspnoea, fever, myalgia, fever, rigors

Question 10

Signs of acute HP

Answer 10

Pyrexia, crackles, hypoxia

Question 11

Symptoms of chronic HP

Answer 11

Progressive, increasing or exertional Dyspnoea, progressive cough, weight loss.

Question 12

Signs of chronic HP

Answer 12

Crackles, clubbing

Question 13

Investigations for acute HP

Answer 13

Bloods, CXR, spirometry

Question 14

Investigations for chronic HP

Answer 14

Blood, CXR, spirometry, DCLA,

Question 15

Investigations for chronic HP

Answer 15

Blood, CXR, spirometry, DCLO.

Question 16

Bloods for acute HP

Answer 16

Neutrophilia & increased ESR

Question 17

CXR for acute HP

Answer 17

Upper zone consolidation, widespread pulmonary infiltrates.

Question 18

Spirometry for acute HP

Answer 18

Reversible restrictive pattern

Question 19

Blood for chronic HP

Answer 19

Positive serum precipitants

Question 20

CXR for chronic HP

Answer 20

Upper lobe fibrosis, honeycomb lung

Question 21

Spirometry for chronic HP

Answer 21

Restrictive defect: Low FEV1 & FVC, high or normal ratio, low gas transfer.

Question 22

DCLO for chronic HP

Answer 22

Reduced.

Question 23

Treatment for Acute HP

Answer 23

Avoid allergen, oxygen, steroid (oral prednisolone), anti-fibrotic therapy in cases of progressive fibrosis (pirfenidone or nintedanib)

Question 24

Treatment for Chronic HP

Answer 24

Avoid allergen & long term steroids

Question 25

Why are corticosteroids used?

Answer 25

To decrease inflammation

Question 26

Why are immunosuppressants used?

Answer 26

To decrease production of antibody.