Creatine kinase and fibrillation potentials in patients with late sequelae of polio

The incidence of an elevated creatine kinase (CK) in a group of polio patients with delayed weakness (15/29) did not differ from polio patients without delayed weakness (9/31) or others with amyotrophic lateral sclerosis (ALS; 10/21). Mean CK in polio patients withoutdelayed weakness (151 IU/L) was lower than the CK in those with delayed weakness (270 IU/L) or ALS (224 IU/L) (P > 0.05). An elevated CK in polio patients with delayed weakness did not correlate with new or residual weakness. These findings suggest that muscle overuse is either not important or inadequately measured by CK. Widely distributed fibrillations were associated with an elevated CK for all polio patients combined (P > 0.01). Fibrillations occurred in more muscles of polio patients with delayed weakness (P > 0.01) and implies that late denervation may play a role in the development of newweakness in some polio patients.