Systemic Lupus Erythematosus with muscle weakness due to Myasthenia Gravis.

Systemic lupus erythematosus (SLE) and myasthenia gravis (MG) are autoimmune diseases, whose association in the same patient is rarely reported. Both pathologies share the following characteristics: affect mainly young women; alternate exacerbation and remission periods; and have positive antinuclear antibody (ANA) test. This case report assesses possible diagnostic hypotheses for the clinical findings of eyelid ptosis and proximal muscle weakness in a female patient recently diagnosed with SLE, who evolved with associated MG.