FA 2019 P. 661 Hypersensitivity Pneumonitis is a mixed type III/IV hypersensitivity reaction to an antigen in the environment. Commonly seen in farmers and people exposed to birds. Presents with Dyspnea, Cough, Chest tightness, headache. It is reversible in the early stages if the allergen is removed.
Hypersensitivity pneumonitisโmixed type III/IV hypersensitivity reaction to environmental antigen. Causes dyspnea, cough, chest tightness, headache. Often seen in farmers and those exposed to birds. Reversible in early stages if stimulus is avoided.
It's a type of restrictive lung disease.
A type of hypersensitivity pneumonitis associated with animal exposure is bird fancierโs lung, in which the major antigens are proteins in avian serum, feces, and feathers, including bloom, the waxy powder coating them (18). Pigeons and parakeets, including budgerigars (a type of parakeet), are the birds most commonly implicated, but poultry, finches, doves, canaries, and other birds also have caused the disease. Exposure to live birds is not necessary to produce hypersensitivity pneumonitis: the illness has resulted from using feather pillows and duvets (19), being exposed to a wreath made from the feathers of a dead pet bird (20), and laundering a pigeon keeperโs overalls (21). Other examples of animal proteins that are known to have caused the disease when inhaled include proteins from the dust of mollusk shells used to make buttons (22) and from animal fur used in garment manufacture
Why the other answer choices aren't correct
A - Not an anaphylactic reaction mainly due to chronicity (consumption of soy, which has glycoproteins that people may have allergies towards)
B - Not asthma (characterized by more acute episodes of bronchoconstriction, wheezing)
D - Anemia (B6, B9, B12), or maybe a pulmonary embolism due to B9 or B12 deficiency --> elevated homocysteine levels --> thrombosis --> DVT?
E - Pulmonary anthrax; The time course would be much more acute, and would also present with symptoms of flu-like symptoms. Rapid death too
This patient is experiencing hypersensitivity pneumonitis from the parakeets. I was thinking M. Avium when I selected parakeets -- I think my logic was flawed given the specifics of the patient's story.
How would you know that it isn't wool sorters disease?
according to uworld hypersensitivity pneumonitis is due to dust and that was also an option....
I also was thinking M. avium here, but hypersensitivity pneumonitis seems to fit with the reticulogranular changes.
how do we know parakeets cause hypersensitivy pneumonitis
Psittacosis (sometimes called ornithosis or parrot disease or parrot fever) is an infection of the lung (pneumonia) caused by the bacterium Chlamydophila (Chlamydia) psittaci.
Signs and symptoms: fever. cough, usually without much phlegm. headache. rash. muscle aches. chest pain. shortness of breath. sore throat.
you get granulomas in both
submitted by โmasonkingcobra(408)
Page 2 has a great picture
https://www.jacionline.org/article/S0091-6749(18)31602-6/pdf