Dermatomyositis, the great Imitator: Case report

Abstract

I nflammatory myopathies associated with autoimmunity are disorders with a heterogeneous clinical presentation, characterized by muscle inflammation and destruction, with varying intensity. Clinically, these disorders usually present with generalized weakness and may also affect other organs and systems in the body, depending on the specific antibodies involved.

The subtype with the highest prevalence in regions near the equator is dermatomyositis. This subtype is characterized by muscle weakness accompanied by cutaneous manifestations. Due to the heterogeneity in presentation and the absence of formal diagnostic criteria, along with the rarity of the pathology, diagnosis can represent a significant clinical challenge, often resulting in delayed diagnosis. At this point, the identification of specific antibodies for myopathies plays a fundamental role, as it helps define associated clinical phenotypes, prognosis, and treatment.

A case is presented of a 21-year-old male patient with a clinical course of 3 months. The clinical presentation included erythema and bilateral eyelid edema, progressive weakness, myalgias, arthritis, constitutional symptoms, and skin lesions on the elbows and knees. The patient consulted multiple specialists without improvement, receiving variable diagnoses. Physical examination revealed skin lesions characteristic of dermatomyositis and weakness. Laboratory tests showed normal CK levels, elevated transaminases and PCR, and the presence of specific myopathy antibodies, including anti-MDA5, anti-Ro52, and anti-NXP2. Electromyography revealed abnormalities consistent with inflammatory myopathy. The patient was treated with corticosteroids and methotrexate, achieving a favorable evolution.