WBR0754

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::Cardiology
Prompt	[[Prompt::A 67 year old man, with a past medical history significant for uncontrolled type 2 diabetes mellitus, hypertension, and dyslipidemia, presents to the emergency department (ED) with acute chest pain. Following appropriate work-up, he is diagnosed with ST-segment elevation myocardial infarction (STEMI) and undergoes cardiac catheterization. The physician advises him to start chronic aspirin therapy for secondary prevention. Six months later, the patient returns to the ED with GI bleeding. Which of the following set of lab values most likely represent the patient's lab values? ]]
Answer A	AnswerA::A
Answer A Explanation	AnswerAExp::Although bleeding time is typically prolonged, patients on aspirin do not typically have prolonged PT.
Answer B	AnswerB::B
Answer B Explanation	AnswerBExp::Patients on aspirin typically have a prolonged bleeding time. Normal PT, PTT, and platelet counts are seen, especially that functional platelet dysfunction occurs without affecting actual platelet numbers.
Answer C	AnswerC::C
Answer C Explanation	AnswerCExp::This shows normal lab values. In patients on aspirin, bleeding time is typically prolonged.
Answer D	AnswerD::D
Answer D Explanation	AnswerDExp::Patients on aspirin do not usually have low platelet count because the platelet dysfunction is functional and does not affect the actual platelet numbers.
Answer E	AnswerE::E
Answer E Explanation	AnswerEExp::Bleeding time in patients on aspirin is usually prolonged and platelet counts are usually within normal ranges.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Aspirin is an irreversible inhibitor of cyclooxygenase (COX1 and COX2) by the process of acetylation. As a result, aspirin causes the reduction of thromboxane A2 synthesis. The overall effects of aspirin include a prolonged bleeding time, without affecting prothrombin time (PT) or partial thromboplastin time (PTT). Platelet dysfunction during aspirin therapy is described as functional, i.e. there is no actual decrease in the numbers of platelet count, but platelet function is inhibited nonetheless. Educational Objective: Aspirin causes a prolonged bleeding time, without affecting PT, PTT, or actual platelet count. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::platelet, WBRKeyword::platelets, WBRKeyword::count, WBRKeyword::bleeding, WBRKeyword::time, WBRKeyword::prothrombin, WBRKeyword::partial, WBRKeyword::thromboplastin, WBRKeyword::PT, WBRKeyword::PTT, WBRKeyword::BT, WBRKeyword::aspirin, WBRKeyword::GI, WBRKeyword::gastrointestinal, WBRKeyword::bleeding, WBRKeyword::acute, WBRKeyword::coronary, WBRKeyword::syndrome, WBRKeyword::STEMI, WBRKeyword::myocardial, WBRKeyword::infarction, WBRKeyword::chronic, WBRKeyword::therapy, WBRKeyword::treatment, WBRKeyword::side, WBRKeyword::effect
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::