WBR0493

Author	[[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Alison Leibowitz)]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Immunology
Sub Category	SubCategory::Endocrine
Prompt	[[Prompt::A 24-year-old female presents to the physician's office for complaints of chronic fatigue. She explains that she was highly active until a few months ago when she began to get excessively tired and sleepy. The patient reports that she is very sad because she is not as active as usual, and also because she has been gaining weight. The review of system revealed chronic constipation and cold intolerance. Which of the following mechanisms is most likely involved in the patient’s condition?]]
Answer A	AnswerA::Hypersensitivity type I
Answer A Explanation	[[AnswerAExp::Type I hypersensitivity disorders include anaphylaxis, atopy, and allergy. Hashimoto's disease is not a type I hypersensitivity disorder.]]
Answer B	AnswerB::Hypersensitivity type II
Answer B Explanation	AnswerBExp::Hashimoto's disease is a type IV hypersensitivity disorder. Grave's disease is considered a form of type II hypersensitivity, because the pathophysiology of Grave's disease involves an antibody against a specific antigen.
Answer C	AnswerC::Hypersensitivity type III
Answer C Explanation	AnswerCExp::Hypersensitivity type III disorders include conditions where an antigen-antibody complex forms and activates the complement system. Hashimoto's disease is not a type III hypersensitivity disorder.
Answer D	AnswerD::Hypersensitivity type IV
Answer D Explanation	[[AnswerDExp::Hypersensitivity type IV disorders include conditions characterized by delayed T-cell mediated immune reactions such as contact dermatitis, tuberculosis testing, delayed transplant rejection, and Hashimoto's disease.]]
Answer E	AnswerE::Not a hypersensitivity disorder
Answer E Explanation	AnswerEExp::Hashimoto's disease is a type IV hypersensitivity disorder.
Right Answer	RightAnswer::B
Explanation	[[Explanation::The patient's symptoms of fatigue, depression, weight gain, chronic constipation, and cold intolerance are suggestive of hypothyroidism, likely caused by Hashimoto's disease. Hashimoto's disease is caused by anti-TPO and is considered a form of type III hypersensitivity. Educational Objective: The patient's symptoms of fatigue, depression, weight gain, chronic constipation, and cold intolerance are suggestive of hypothyroidism, likely caused by Hashimoto's disease. Hashimoto's disease is caused by anti-TPO and is considered a form of type III hypersensitivity. References: First Aid 2014 page 320]]
Approved	Approved::Yes
Keyword	WBRKeyword::Hypersensitivity, WBRKeyword::hypothyroidism, WBRKeyword::Hashimoto, WBRKeyword::immune, WBRKeyword::fatigue, WBRKeyword::depression, WBRKeyword::immune system
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::