Benign prognosis in idiopathic hyper-CK-emia

We report on the long-term follow-up in 31 patients with idiopathic hyper-CK-emia. At referral, all patients underwent a neurological interview and examination. Ancillary investigations included an open muscle biopsy and electromyography (EMG) in almost all, and other ancillary tests in some patients. After a follow-up period of 7.2 (mean; range 4-18) years, 74% of the patients had a final evaluation. The most common complaints at referral were fatigue and myalgia. EMG and muscle biopsy demonstrated minor, non-diagnostic abnormalities in 30 and 71% of patients, respectively. At follow-up, the pattern and the number of complaints had not changed substantially. One patient developed a sensory polyneuropathy. Neurological abnormalities were absent in all other patients. In conclusion, long-term follow-up of patients with idiopathic hyper-CK-emia does not reveal clinical deterioration. It seems justifiable to refrain from routine long-term follow-up in these patients.