General Pathology USMLE Step 1 Practice Question
A 19-year-old woman with known peanut allergy accidentally ingests a dessert containing peanuts. Within minutes, she develops diffuse urticaria, wheezing, and lightheadedness. Vital signs show BP 88/52 mmHg, HR 118/min, RR 22/min, and SpO2 92% on room air. Serum tryptase level is elevated at 8.5 ng/mL. She denies angioedema. Which pathophysiologic mechanism most likely produced this acute systemic reaction?
Answer choices
- AComplement deficiency with recurrent infections
- BBradykinin release from contact system activation
- CIgE mediated mast cell degranulation with histamine releaseCorrect answer
- DImmune complex deposition in postcapillary venules
- ECytotoxic T cell injury via perforin
- FIgG-mediated cross-linking of high-affinity IgG receptors on basophils
See the full explanation
Get the correct-answer rationale, why each distractor is wrong, the underlying mechanism, and high-yield associations — plus adaptive practice that targets your weak areas — with a free MedBoardPRO account.