Peripheral Neuroanatomy, Human Anatomy, USMLE Step 1 - Full Vignette with Extended Explanations скачать в хорошем качестве

Peripheral Neuroanatomy, Human Anatomy, USMLE Step 1 - Full Vignette with Extended Explanations

A 52-year-old woman acutely develops left eyelid droop, a smaller pupil, and neck pain right after sudden neck rotation, with no trauma or significant neurological deficits. What clinical reasoning can guide your assessment in this scenario with focal oculosympathetic symptoms and neck discomfort? What are the critical diagnostic challenges when evaluating an abrupt presentation involving unilateral ptosis, miosis, and anhidrosis? VIDEO INFO Category: Peripheral Neuroanatomy, Human Anatomy, USMLE Step 1 Difficulty: Hard - Advanced level - Challenges experienced practitioners Question Type: Diagnostic Step Case Type: Emergency - Emergency scenario requiring urgent decision-making Explore more ways to learn on this and other topics by going to https://endlessmedical.academy/auth?h... QUESTION A 52-year-old woman is brought to a U.S. emergency department 90 minutes after noticing abrupt left eyelid droop with a smaller left pupil while she was reaching to a high shelf and quickly rotated her neck. She reports new dull aching on the left side of the neck beginning at the same moment. She denies head trauma, diplopia, limb weakness, dysarthria, dysphagia, or visual field loss.... OPTIONS A. CT angiography of the head and neck with intravenous iodinated contrast performed immediately in the emergency department to evaluate the cervical carotid and vertebral arteries for dissection. B. MRI of the brain and neck with gadolinium and fat-suppressed T1 sequences plus contrast-enhanced MRA obtained urgently within 12-24 hours to evaluate arterial wall hematoma. C. Topical cocaine 4% eye drop pharmacologic confirmation test (2 drops in each eye once in clinic today) before any cross-sectional vascular imaging. D. Carotid duplex ultrasound of the neck arteries obtained first as a screening test prior to any cross-sectional angiography. CORRECT ANSWER A. CT angiography of the head and neck with intravenous iodinated contrast performed immediately in the emergency department to evaluate the cervical carotid and vertebral arteries for dissection. EXPLANATION CT angiography of the head and neck with intravenous iodinated contrast performed immediately in the emergency department to evaluate the cervical carotid and vertebral arteries for dissection. In acute painful ipsilateral Horner syndrome after neck rotation-classic for cervical (often internal carotid) artery dissection-the most time-sensitive, high-yield test is immediate CTA because it rapidly depicts luminal abnormalities (tapered stenosis, flap, pseudoaneurysm) across both carotid and vertebral systems in one acquisition. Modern emergency pathways prioritize speed and availability; CTA is widely accessible, fast, and adequately sensitive to trigger antithrombotic therapy and further management, consistent with the 2024 American Heart Association scientific statement and the 2025 ACR Appropriateness Criteria for Horner syndrome. MRI/MRA with vessel-wall fat-suppressed T1 can show intramural hematoma and is an excellent study, but it is slower, often less available at triage, and not superior as the very first test when the clinical picture demands immediate vascular assessment; it is best used as a confirmatory or complementary study within hours. Pharmacologic confirmation of Horner physiology with topical cocaine 4% adds delay and does not identify the dangerous cause.... --------------------------------------------------- Our cases and questions come from the https://EndlessMedical.Academy quiz engine - multi-model platform. Each question and explanation is forged by consensus between multiple top AI models (GPT, Claude, Grok, etc.), with automated web searches for the latest research and verified references. Calculations (e.g. eGFR, dosages) are checked via code execution to eliminate errors, and all references are reviewed by several AIs to minimize hallucinations. Important note: This material is entirely AI-generated and has not been verified by human experts; despite stringent consensus checks, perfect accuracy cannot be guaranteed. Exercise caution - always corroborate the content with trusted references or qualified professionals, and never apply information from this book to patient care or clinical decisions without independent verification. Clinicians already rely on AI and online tools - myself included - so treat this book as an additional focused aid, not a replacement for proper medical education. Visit https://endlessmedical.academy for more AI-supported resources and cases. This material can not be treated as medical advice. May contain errors. ---------------------------------------------------