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NBME 20 Answers

nbme20/Block 4/Question#21

A 47-year-old woman comes to the physician because ...

Contact with parakeets

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submitted by hayayah(407),

Hypersensitivity pneumonitis—mixed 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.

 +3  upvote downvote
submitted by monoloco(54),

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.

 +1  upvote downvote
submitted by breis(11),

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.

charcot_bouchard  Update on my prev comment : Yes this is psittacosis. not hypersensitivity pneumonitis. How do u know? Lymphocyte and Presence of Granuloma - response to intracellular chlamydia. Now HS can also cause loose granuloma too and the clinical picture still more look like HS You know what ......... fuck this ques +  
shemle  Here Pt. doesn't have fever! +  

How would you know that it isn't wool sorters disease?

cienfuegos  FA 2018 137: inhalation of spores leads to flu-like symptoms that progress quickly to fever, pulmonary hemorrhage, mediastinitis and shock, with imaging possibly showing widened mediastinum +  

 +0  upvote downvote
submitted by beeip(63),

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

smc213  FA18 p.657 bird exposure--> HSN pneumonitis (restrictive lung disease) and FA18 p.214 granulomatous diseases: foreign material-->HSN pneumonitis. I had to make sense of it since I didn't know it was HSN pneumonitis at first. +  

according to uworld hypersensitivity pneumonitis is due to dust and that was also an option....

amarousis  so it's definitely dust but the specific type of dust was the most important in this question. the fact that they mentioned the birds is important. the dusty books would cause it but the bird dust is more important -.- +  
charcot_bouchard  Hypersensitivity Pneumonitis - Organic dust (like moldy hay) Pneumocniosis - Inorganic dust none help here though because both will present with same restrictive lung disease picture. i think since dust in library arent neither organic or inorganic and also u dont see many librarians with lung disease but bird ownership is specifically mentioned as cause of HP disease. +