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

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

A 58-year-old man on chronic prednisone presents with several days of pruritus, dark urine, pale stools, and episodic right upper-quadrant pain radiating to the back. Exam reveals scleral icterus, excoriations, and RUQ tenderness; labs show cholestatic liver enzyme elevation. Imaging demonstrates gallstones and a dilated common bile duct without definite stone. How should you approach the diagnostic workup for suspected biliary obstruction in this scenario, taking into account clinical stability and the need to accurately define biliary anatomy while minimizing procedural risk? VIDEO INFO Category: Hepatobiliary Anatomy, Human Anatomy, USMLE Step 1 Difficulty: Hard - Advanced level - Challenges experienced practitioners Question Type: Diagnostic Step Case Type: Typical Presentation Explore more ways to learn on this and other topics by going to https://endlessmedical.academy/auth?h... QUESTION A 58-year-old man with polymyalgia rheumatica treated with prednisone 7.5 mg daily presents with 4 days of generalized pruritus, dark urine, pale stools, and episodic postprandial right upper-quadrant pain radiating to the back. He denies fever or rigors and has had no prior biliary instrumentation. He is a former Army mechanic, does not drink alcohol, and lives with his spouse. He takes prednisone, omeprazole, and acetaminophen as needed.... OPTIONS A. Obtain MRCP with heavily T2-weighted sequences within 24-48 hours at a center experienced in hepatobiliary imaging to define the level of obstruction and variant ductal anatomy, reserving ERCP for confirmed stones or clinical cholangitis. B. Perform endoscopic ultrasound within 24 hours by an advanced endoscopist to triage for same-session ERCP, accepting sedation and procedural resource use despite similar accuracy to MRCP and absent cholangitis. C. Proceed directly to therapeutic ERCP now with sphincterotomy and stone extraction despite no cholangitis, prioritizing immediate intervention over noninvasive anatomic definition and accepting a 5-10% adverse-event risk. D. Arrange percutaneous transhepatic cholangiography with external drainage as the initial investigation to map a presumed stricture and decompress the system before any endoscopy. CORRECT ANSWER A. Obtain MRCP with heavily T2-weighted sequences within 24-48 hours at a center experienced in hepatobiliary imaging to define the level of obstruction and variant ductal anatomy, reserving ERCP for confirmed stones or clinical cholangitis. EXPLANATION In a hemodynamically stable patient with an intermediate likelihood of choledocholithiasis, the safest next diagnostic step that still accurately defines biliary anatomy is noninvasive MRCP at an expert center. MRCP with heavily T2-weighted sequences visualizes fluid-filled ducts, can delineate the level of obstruction and variant anatomy, and avoids the 5-10% adverse-event risk of ERCP. Per ASGE 2019 and NICE CG188, intermediate-risk patients should undergo MRCP or EUS before therapeutic ERCP. Given the absence of cholangitis and the goal to minimize procedural risk, MRCP is preferred in many systems because it avoids sedation and pancreatic manipulation while maintaining high accuracy. EUS within 24 hours is a reasonable near-alternative, often used when same-session ERCP is available, but it still commits resources and sedation without demonstrated superiority to MRCP in this setting.... Further reading: Links to sources are provided for optional further reading only. The questions and explanations are independently authored and do not reproduce or adapt any specific third-party text or content. --------------------------------------------------- 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 (i.e. Open AI 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 content to patient care or clinical decisions without independent verification. Clinicians already rely on AI and online tools - myself included - so treat this content 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. ---------------------------------------------------