Musculoskeletal Pathology, Pathology, USMLE Step 1 - Full Vignette with Extended Explanations скачать в хорошем качестве

Musculoskeletal Pathology, Pathology, USMLE Step 1 - Full Vignette with Extended Explanations

Four young recruits develop acute joint pain and swelling after intense physical activity, each presenting with distinct symptoms including joint effusion, erythema, and localized tenderness. Given their recent exertion, medication use, and prior medical histories, how should you determine which patient needs immediate joint aspiration for diagnostic clarity? What clinical factors should guide your approach in prioritizing urgent arthrocentesis for suspected crystal arthropathies? VIDEO INFO Category: Musculoskeletal Pathology, Pathology, USMLE Step 1 Difficulty: Easy - Basic level - Suitable for medical students Question Type: Differential Testing Case Type: Multi Patient Explore more ways to learn on this and other topics by going to https://endlessmedical.academy/auth?h... QUESTION Four recruits present to the base clinic after a week of load-bearing marches. Vitals at triage are stable in all four. Medications used by the group are occasional acetaminophen; none take daily NSAIDs. One recruit has a latex contact rash history. No one reports prior crystal-proven arthritis. Patient A (22-year-old man) stepped on an uneven rock yesterday with an inversion twist.... OPTIONS A. Patient C: Sudden hot, swollen knee with large effusion after marching; prior knee film showed chondrocalcinosis; has secondary hyperparathyroidism; perform diagnostic arthrocentesis with polarized light microscopy. B. Patient A: Inversion ankle injury with point tenderness over the anterior talofibular ligament, normal radiographs, and intact weight-bearing; manage as sprain without joint aspiration. C. Patient B: Painful red great toe with nail-fold fluctuance from tight boots; treat as paronychia with local drainage and wound care, not synovial analysis. D. Patient D: Lateral elbow ache with full motion and no effusion; consistent with lateral epicondylitis; use activity modification and local measures, not joint aspiration. CORRECT ANSWER A. Patient C: Sudden hot, swollen knee with large effusion after marching; prior knee film showed chondrocalcinosis; has secondary hyperparathyroidism; perform diagnostic arthrocentesis with polarized light microscopy. EXPLANATION Patient C has an acutely hot, swollen knee with a large effusion and painful restricted motion after exertion, a prior radiograph showing chondrocalcinosis, and a history of secondary hyperparathyroidism. These features make calcium pyrophosphate deposition disease highly likely, but septic arthritis and gout remain urgent differentials. The most discriminating, management-directing test is immediate synovial fluid analysis with polarized light microscopy and culture. This directly identifies monosodium urate (needle-shaped, strongly negatively birefringent) or calcium pyrophosphate crystals (rhomboid, weakly positively birefringent) and concurrently evaluates for infection. Per the 2020 American College of Rheumatology gout guideline and the 2023 ACR/EULAR CPPD criteria, crystal identification and synovial culture are the gold standards to distinguish these entities. Patient A s inversion ankle injury with focal tenderness over the anterior talofibular ligament, normal radiographs, no effusion, and preserved weight-bearing is typical of a lateral ankle sprain; aspiration is unnecessary. Patient B s warm, red great toe localizes to the nail fold with fluctuance consistent with paronychia needing local drainage, not synovial analysis.... 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. ---------------------------------------------------