WBR0493
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Immunology |
| Sub Category | SubCategory::Endocrine |
| Prompt | [[Prompt::A 24-year-old female presented to her primary care physician for chronic fatigue. She is a graduate student and has always been very active until a few months ago when she started to get tired and sleepy more than usual. The patient reported 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 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. Grave's disease is not a type I hypersensitivity disorder.]] |
| Answer B | AnswerB::Hypersensitivity type II |
| Answer B Explanation | AnswerBExp::Grave's disease is caused by antibodies against TSH receptors and it is considered a form of type II hypersensitivity because 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. Grave'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 and delayed transplant rejection. Grave's disease is not a type III hypersensitivity disorder.]] |
| Answer E | AnswerE::Not a hypersensitivity disorder |
| Answer E Explanation | AnswerEExp::Grave's disease is a type II hypersensitivity disorder. |
| Right Answer | RightAnswer::B |
| Explanation | [[Explanation::The patient's symptoms of fatigue, chronic constipation and cold intolerance are suggestive of hypothyroidism. The most common cause of hyperthyroidism in this age group is Hashimoto's disease. Hashimoto's disease is caused by anti-TPO and it is considered a form of type IV hypersensitivity.
Educational Objective: Grave's disease, a cause of hyperthyroidism, is a type II hypersensitivity condition; whereas Hashimoto's disease, a cause of hypothyroidism, is a type IV hypersensitivity. |
| Approved | Approved::No |
| Keyword | WBRKeyword::Hypersensitivity, WBRKeyword::Grave's disease |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |