Nolla Solé, Joan MiquelNarváez García, Francisco Javier2026-02-112026-02-112026-01-27https://hdl.handle.net/2445/226795This document is part of the Clinical Cases for Residents collection, an educational initiative designed for postgraduate training in Rheumatology and applicable to other medical specialties involved in the management of systemic inflammatory diseases. Its primary objective is to enhance clinical reasoning, syndromic assessment, and the structured development of differential diagnoses in complex clinical scenarios. The case describes a young adult presenting with persistent fever, marked systemic inflammation, prominent musculoskeletal involvement, and mucocutaneous manifestations, leading to a comprehensive diagnostic evaluation. Particular emphasis is placed on the differential diagnosis of hyperinflammatory syndromes in adults and on the identification of cardiac involvement as a key diagnostic discriminator. The clinical reasoning process supporting the diagnosis of adult-onset Kawasaki disease is discussed in detail. The document provides relevant clinical, analytical, and imaging data, along with a pathophysiological framework to support interpretation. The case is conceived as a teaching tool for medical residents, promoting group discussion, guided analysis, and the integration of multidisciplinary findings. It forms part of a broader collection aimed at strengthening advanced competencies in differential diagnosis, integrative clinical reasoning, and evidence-based decision-making in real-world clinical practice.5 p.application/pdfengcc by-nc-nd (c) Nolla Solé, Joan Miquel et al., 2026http://creativecommons.org/licenses/by-nc-nd/4.0/ReumatologiaMedicina internaEstudi de casosFormulació clínicainfo:eu-repo/semantics/otherinfo:eu-repo/semantics/openAccess