Introduction: McArdle disease is a rare recessive disorder of glycogen metabolism, related to muscle phosphorylase deficiency. It usually presents in adolescence or early adulthood with muscle cramps, exercise intolerance, easy fatigability, and progressive weakness as glycogen is the primary source of energy for intense muscle activity. Few reports described the association of McArdle disease and type 2 diabetes and some authors suggested that hyperglicemia and hyperinsulinemia may improve muscle symptoms. In fact, sucrose ingestion before exercise is one of the proposed treatments for this disease.
Clinical case: A 69-year-old caucasian male with previous medical history of insulin-treated type 2 diabetes mellitus (diagnosed 30 years before), McArdle disease (diagnosed 15 years before, by muscle biopsy) and colon carcinoma (6 years before, treated with surgery and chemotherapy, without evidence of recurrence) presented with severe pain and weakness in left lower extremity (during last 4 months) and weight loss. Previously, he did routine moderate exercise, without symptoms. On physical examination, he had proximal muscular athophy (more in anterior compartment of left thigh), very reduced reflexes (more in left limb), and a small antero-lateral area of hypoesthesia in left thigh. HbA1c was 9.4%. Electromyography revealed a sensitive and motor polyradiculoneuropathy (with predominantly lombar expression) compatible with the diagnosis of BrunsGarland syndrome. Patient was submitted to symptomatic treatment (gabapentin and duloxetine), physiotherapy and glycemic control optimization.
Discussion: In this patient with simultaneous miopathy and neuropathy predisposing disease, this clinical presentation originated a challenging differential diagnosis. BrunsGarland syndrome is a rare complication of diabetes and more frequent in patients under good metabolic control. Another relevant point is related to the eventual contribution of hyperglicemia to McArdle disease absence of symptoms. This fact may be taken into account in deciding glycemic treatment goals in this patient with long duration diabetes.
30 Apr - 04 May 2011
European Society of Endocrinology