Extrinsic Allergic Alveolitis Flashcards
Describe Extrinsic Allergic Alveolitis?
In sensitized individuals, inhalation of an allergic antigen causes a hypersensitivity reaction
What time of Hypersensitivity reaction is this?
Type 3 - Immune Complex Mediated
Describe this type of hypersensitivity reaction?
In the blood there are circulating antibodies. These bind to antigens to form immune complexes. These immune complexes increase in size until they become stuck in small vessels where they activation the inflammation process
Describe the immunology behind acute part of Extrinsic Allergic Alveolitis?
The immune complexes are deposited in the walls of the bronchioles and alveoli
This causes infiltration by inflammatory cells (Macrophages and Neutrophils)
Describe the symptoms of the acute extrinsic allergic alveolitis?
Wheeze Malaise Dry Cough Breathlessness Fever
Extrinsic Allergic Alveolitis is also sometimes called Hypersensitivity Pneumonitis.. What does this mean?
Hypersensitivity of the alveoli due to inhaled organic dust
Describe the chronic part of Extrinsic Allergic Alveoliti’s?
Recruitment of inflammatory cells will lead to granuloma formation
This leads to fibrosis of the bronchioles
Describe Farmer’s Lung?
This is caused by inhalation of mouldy hay particles
Causes shortness of breath and malaise
Lenghthy exposure can lead to lung damage
What kind of Immuglobulins are involved in Allergic Alveolitis?
IgG
Describe Bird Fancier’s Lung
This is caused by exposure to bird droppings
Causes shortness of breath
General symptoms for Extrinsic Allergic Alveolitis?
Dry Cough Fever Rigors Malaise Dyspnoea Crackles
Investigations
FBC
Lung Function Test
What kind of lung disease is Extrinsic Allergic Alveoli’s?
Restrictive (Fibrosis)
Treatment for Extrinsic Allergic Alveolitis?
Avoidance
Oxygen
Oral Prednisolone
