General Pathology USMLE Step 1 Practice Question
A 41-year-old male scuba diver ascends rapidly following equipment malfunction. He presents with acute dyspnea, dizziness, severe shoulder and knee pain, and skin mottling. Vital signs show BP 118/76, HR 112, RR 22, SpO2 88% on room air. Chest X-ray reveals pulmonary edema. Serum nitrogen levels are markedly elevated. He denies recent decompression illness. Arterial blood gas shows hypoxemia without hypercapnia. Which mechanism best explains his clinical presentation?
Answer choices
- AFibrin thrombi due to sepsis
- BNitrogen gas bubble formation in blood and tissuesCorrect answer
- CCholesterol crystal embolization
- DPlatelet rich microthrombi from ADAMTS13 deficiency
- ESeptic emboli from endocarditis
- FOxygen toxicity from excessive dissolved oxygen in arterial blood
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.