Background: Protracted febrile myalgia (PFM) is a rare but severe form of myalgia mainly occurring in pediatric patients with familial Mediterranean fever (FMF). PFM imaging and histopathological data remain scarce. Objectives: A comprehensive clinical, imaging, and histopathological characterization of PFM was performed by retrospectively analyzing a reference center cohort of adult patients with FMF and myalgia, and by a PubMed search of well-described cases with PFM. Results: Among 56 adults with FMF from our center, 32 (57.1%) experienced myalgia, which was generalized in 21 (37.5%) and affected lower limbs in 11 (19.6%) subjects. One (1.8%) patient suffered PFM, mainly affecting calves and Achilles tendons. From our patient’s detailed information and the data from 123 PFM cases reported in the literature, PFM was characterized as usually presenting with fever and severe generalized myalgia, with occasional involvement of lower legs and calves. It is mainly associated (in >90% of cases) with the pathogenic mutation M694V in the MEFV gene. Raised acute phase reactants and normal creatine kinase levels are constant. High glucocorticoid doses are useful in most patients, and sustained colchicine treatment protects from PFM recurrences. MRI may identify a variable degree of muscle inflammatory changes, especially subfascial and myofascial lesions with extension to tendinous structures. PFM histopathology is characterized by T-cell rich inflammatory infiltrates and vasculitis mainly involving the fasciae and myofascial areas, with a lower muscle extent. Conclusions: PFM can occur in children and adults and appears to be clinically manifested as fasciitis/tendinitis caused by a vasculitis of the fasciae rather than a major muscle vasculitis.

Background/Objectives: Hospitalisations in systemic lupus erythematosus (SLE) reflect disease severity, accumulated damage, and the burden of comorbidity, remaining a major determinant of healthcare utilisation. Recent evidence suggests a shift from flare-driven admissions toward complications related to infections, comorbidities, and long-term treatment effects. We aimed to analyse the causes, characteristics, and outcomes of hospital admissions in patients with systemic lupus erythematosus (SLE) over a 30-year period in a tertiary referral centre in Catalonia (Spain) and to evaluate changes over time and prognostic factors associated with adverse outcomes. Methods: A retrospective observational study was conducted including all SLE patients admitted to the Department of Autoimmune Diseases at Hospital Clínic de Barcelona between June 1995 and December 2024. Admissions lasting less than 48 h or lacking clinical documentation were excluded. Variables analysed included demographics, disease duration, comorbidities, cause of admission, treatments, and outcomes. A composite outcome was defined as intensive care unit (ICU) admission, 30-day readmission, or prolonged hospital stay. Statistical analyses included univariate and multivariate regression models. Results: Among the 1216 hospital admissions, SLE flares and infections were the most frequent causes. Over the study period, admissions due to infections increased significantly and, in the last five years, exceeded those related to disease flares (33.7% vs. 26.1%). Patients hospitalized for flares were younger and had a shorter disease duration, whereas infection-related admissions were more common among older patients, those with overlap syndromes, and those with higher damage scores. Vascular events and SLE flares were independently associated with poorer outcomes. Although antimalarial use increased over time, it remained suboptimal, largely due to drug toxicity and newly diagnosed cases (from 45.2% to 69.7%; p < 0.001). Treatment strategies also evolved, with a shift toward lower glucocorticoid doses (from 14.5% to 38.3%; p < 0.001), and mycophenolate mofetil replacing cyclophosphamide as the preferred immunosuppressive agent. Conclusions: Hospitalisation patterns in SLE have shifted over time, with infections emerging as the leading cause of admission. This trend reflects an evolving patient profile characterized by older age, greater accumulated damage, comorbidities, and increased exposure to immunosuppressive therapies. These findings underscore the need for optimized infection prevention strategies and individualized treatment approaches to improve outcomes in contemporary SLE care.

Background/Objectives: To analyse the causes, characteristics, and outcomes of hospital admissions in patients with systemic lupus erythematosus (SLE) over a 30-year period in a tertiary referral centre in Catalonia, and to evaluate temporal trends and prognostic factors associated with adverse outcomes. Methods: A retrospective observational study was conducted including all SLE patients admitted to the Department of Autoimmune Diseases at Hospital Clínic de Barcelona between June 1995 and December 2024. Admissions lasting less than 48 hours or lacking clinical documentation were excluded. Variables analysed included demographics, disease duration, comorbidities, cause of admission, treatments, and outcomes. A composite outcome was defined as intensive care unit (ICU) admission, 30-day readmission, or prolonged hospital stay. Statistical analyses included univariate and multivariate regression models. Results: Among the 1,216 hospital admissions, SLE flares and infections were the most frequent causes. Over the study period, admissions due to infections increased significantly and, in the last five years, exceeded those related to disease flares (33.7% vs. 26.1%). Patients hospitalized for flares were younger and had a shorter disease duration, whereas infection-related admissions were more common among older patients, those with overlap syndromes, and those with higher damage scores. Vascular events and SLE flares were independently associated with poorer outcomes. Although antimalarial use increased over time, it remained suboptimal, largely due to drug toxicity and newly diagnosed cases (from 45.2% to 69.7%; p< 0.001). Treatment strategies also evolved, with a shift toward lower gluco-corticoid doses (from 14.5% to 38.3%; p< 0.001), and mycophenolate mofetil replacing cyclophosphamide as the preferred immunosuppressive agent. Conclusions: Hospitalisation patterns in SLE have shifted over time, with infections emerging as the leading cause of admission. This trend reflects an evolving patient profile characterized by older age, greater accumulated damage, comorbidities, and increased exposure to immunosuppressive therapies. These findings underscore the need for optimized infection prevention strategies and individualized treatment approaches to improve outcomes in contemporary SLE care.