Wave of renal impairment.

We present a case of a 51-year-old man who went to the emergency department after an almost-drowning episode, presenting with muscular weakness, myalgia and dark urine. Laboratory data showed a severe rhabdomyolysis (creatine kinase 497 510 U/L). Despite aggressive fluid therapy, an oliguric acute kidney injury was established with temporary need of haemodialysis. The patient had a longtime history of exercise intolerance and family history of a metabolic myopathy, namely a sister with McArdle's disease. The genetic test was positive. McArdle's disease is an autosomal recessive disorder caused by mutations in the muscle glycogen phosphorylase gene that encodes the myophosphorylase. The main symptom consists in exercise intolerance and the most severe complication is rhabdomyolysis with acute renal failure. Metabolic myopathies, such as McArdle's disease, should be considered in patients with acute renal failure due to unexplained severe rhabdomyolysis, especially if there are chronic complaints of exercise intolerance and positive family history. © BMJ Publishing Group Ltd (unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.