[Raised creatine-kinase serum activity: not necessarily a sign of disease]

Hyper-creatine-kinase(CK)-aemia in patients without neurological abnormalities may be sign of a subclinical neuromuscular disorder. Initial screening of patients with hyper-CK-aemia must include careful history taking and a neurological examination. Appropriate blood tests to exclude aeanthocytosis and glycogen storage disease type II must be done. The diagnostic value of a skeletal muscle biopsy and electromyography is small. A muscle biopsy to exclude dystrophinopathy is indicated if the CK activity exceeds 5 times the upper limit of the normal range. If the results of initial screening are normal, patients with idiopathic hyper-CK-aemia fare quite well at 7-year follow-up. Also, standardized exercise tests in these patients have provided no evidence of increased muscle vulnerability. Thus, in most of these patients, hyper-CK-aemia probably does not reflect disease.