A rare case of serologically diagnosed overlap syndrome presents as an idiopathic inflammatory myositis without any overlapping features
Keywords:Overlap syndrome, IIM, Autoimmune, Differential diagnoses
Overlap syndrome is a rare inflammatory rheumatic condition that shares features suggestive of at least two distinct autoimmune diseases with a reported prevalence of less than 34/100,000 persons and an incidence of less than 20/million/year. One example of an overlap syndrome is the presence of dermatomyositis or polymyositis with other autoimmune afflictions such as systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), or Sjogren’s syndrome. We present a case report of a 22-year-old male presented with progressive weakness in both upper and lower limbs without any other significant complaints. On investigation, serology revealed antibodies suggestive of overlap syndrome, which on further investigations, categorized as idiopathic inflammatory myositis (IIM). This shows that overlap syndrome, as an IIM, is one of the differential diagnoses in patients presenting with progressive extremity weakness involving both extremities even if there is no involvement of any sensory function.
Hilton-Jones D. Observations on the classification of the inflammatory myopathies. Presse Med. 2011;40(4):e199-208.
Meyer A, Meyer N, Schaeffer M, Gottenberg JE, Geny B, Sibilia J. Incidence and prevalence of inflammatory myopathies: a systematic review. Rheumatology. 2015;54(1):50-63.
Troyanov Y, Targoff IN, Tremblay JL, Goulet JR, Raymond Y, Senécal JL. Novel Classification of Idiopathic Inflammatory Myopathies Based on Overlap Syndrome Features and Autoantibodies. Medicine (Baltimore). 2005;84(4):231-49.
Schmidt J. Current Classification and Management of Inflammatory Myopathies. J Neuromuscul Dis. 2018;5(2):109-29.
Senécal J, Raynauld J, Troyanov Y. Editorial: A New Classification of Adult Autoimmune Myositis. Arthritis Rheumatol. 2017;69(5):878-84.
Dalakas MC. Review: An update on inflammatory and autoimmune myopathies. Neuropathol Appl Neurobiol. 2011;37(3):226-242.
Silva AMS, Campos ED, Zanoteli E. Inflammatory myopathies: an update for neurologists. Arq Neuropsiquiatr. 2022;80(5):238-48.
Malik A, Hayat G, Kalia JS, Guzman MA. Idiopathic Inflammatory Myopathies: Clinical Approach and Management. Front Neurol. 2016;7(5).
Oddis CV. Idiopathic inflammatory myopathy: management and prognosis. Rheum Dis Clin North Am. 2002;28(4):979-1001.
Nuño L, Joven BE, Carreira PE, Barrio J, Maldonado-Romero V, Larena-Grijalba C et al. FRI0449 Overlap myositis and primary myositis: clinical outcomes and prognosis. Ann Rheum Dis. 2018;77(2):753-54.