Profile of Sharp Syndrome in Thiès: A Preliminary Study in Two Internal Medicine Departments

Abstract

Introduction: Sharp syndrome is a rare autoimmune disease characterized by the presence of autoantibodies targeting the U1 ribonucleoprotein (U1RNP), with significant clinical polymorphism that may include features of systemic sclerosis, systemic lupus erythematosus, inflammatory myopathies, and rheumatoid arthritis. Several classification criteria can be used for diagnosis, including those of Sharp, Alarcon-Segovia, Kasukawa, and Kahn. The clinical picture is characterized by cutaneous and mucosal, joint, and muscular involvement and may be complicated by pulmonary arterial hypertension or diffuse interstitial lung disease. The objectives of this study were to determine the prevalence and to describe the clinical, paraclinical, evolutionary, and therapeutic aspects of Sharp syndrome. Methods: This was a retrospective, descriptive, analytical longitudinal study conducted from January 2014 to January 2024 in two internal medicine departments: the Regional Hospital Center of Thiès and the Mame Abdou Aziz SY Dabakh Hospital in Tivaouane. The study included patients with a confirmed diagnosis of mixed connective tissue disease. Results: The prevalence was 0.70%, with a female predominance. The mean age was 35.8 years. Regarding sociodemographic characteristics, 80% of the patients were married, two had a university education, two were housewives, and three lived in peri-urban areas. All three cases came from the Amadou Sakhir Ndiéguene Regional Hospital Center in Thiès. One patient had type 2 diabetes. Three patients were nulligravida, and one was using oral contraception. General health deterioration was observed in 80% of cases. Clinically, 80% presented with inflammatory-type arthralgia involving both small and large peripheral joints. Raynaud’s phenomenon and “puffy fingers” were found in 60% of patients. One patient had myalgia localized to the lower limbs. Pulmonary involvement included two cases of interstitial lung disease with pulmonary fibrosis. No cases of pulmonary arterial hypertension were recorded. Cardiac involvement consisted of one patient with a left anterior fascicular block on ECG. Gastrointestinal manifestations included epigastric pain suggestive of ulcer in 60% of cases. Biologically, an inflammatory syndrome was present in two patients. Immunologically, all patients tested positive for antinuclear antibodies and anti-U1RNP antibodies, with titers greater than 241. All patients were treated with corticosteroids and hydroxychloroquine. The mean follow-up duration was 4.4 years. Conclusion: Sharp syndrome had a low prevalence in our study, with articular involvement being the most common clinical manifestation. Interstitial lung disease was the most frequent complication, and all patients were treated with corticosteroids and antimalarial agents. A multicenter national study is warranted to gain a more comprehensive understanding of this rare disease.