Causes. The causes of rhabdomyolysis typically also give clinical clues to the severity of the disease. Some causes include suffering a crush injury, specific medication, overly strenuous exercise, drug abuse, viruses, heat stroke or inherited muscle conditions. The classic example of rhabdomyolysis involves the marathon runner that collapses at the end of their race. This example includes the risk of strenuous exercise, but also potentially the risk of heat stroke. Evaluation of rhabdomyolysis will include blood tests and likely urine studies. Diagnosis of rhabdomyolysis may be made on the basis of clinical symptoms; however, it will be confirmed and quantified using a laboratory marker called Creatine Kinase, (Previously termed Creatine Phosphokinase and abbreviated CK). CK levels greater than 1000 U/L indicate rhabdomyolysis while levels 5000 U/L and above indicate the diagnosis of severe disease. Concerns regarding the potential of kidney failure begin at Creatine Kinase levels of 5,000-6,000 U/L.