Autonomic Pharmacology USMLE Step 1 Practice Question
A 67-year-old man with a history of metastatic prostate cancer and known thoracic spinal cord compression presents to the emergency department with acute onset paraplegia and urinary retention. His wife reports he was started on doxazosin 4 mg daily yesterday for lower urinary tract symptoms. Current vital signs are BP 78/45 mmHg, HR 112/min, RR 22/min, temperature 37.2°C, and SpO2 97% on room air. Physical examination reveals bilateral lower extremity weakness (3/5) with preserved sensory function. MRI of the thoracic spine shows no interval change in the size of the known cord compression compared to imaging 2 months prior. Laboratory values include hemoglobin 7.9 g/dL, creatinine 1.6 mg/dL, and normal lumbar puncture studies. Which of the following mechanisms best explains this patient's acute neurologic deterioration?
Answer choices
- ADirect doxazosin-induced axonal demyelination via disruption of myelin protein synthesis
- BAcute spinal cord ischemia secondary to doxazosin-induced systemic hypotensionCorrect answer
- CHemorrhagic transformation of the preexisting spinal cord lesion due to increased intracranial pressure
- DAllergic hypersensitivity reaction with vasculitis affecting spinal cord vasculature
- ENeoplastic progression with acute epidural metastatic disease causing cord compression
- FInfectious myelitis triggered by immunosuppression from doxazosin therapy
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