By Jordana Bieze Foster
Researchers from the University of Sydney remain perplexed by the emergence of hand tremor as a predictor of calf cramp in children with Charcot-Marie-Tooth disease but theorize that the relationship may involve fatigue.
As reported in the December 2011 issue of Neurology, the investigators analyzed 81 children with CMT type 1A and found that 26% suffered from calf cramps. Variables that were significantly associated with calf cramp included older age, presence of hand tremor, increased foot inversion, eversion, dorsiflexion and plantar flexion strength, fist grip strength, and better performance on long jump and a manual dexterity test. However, the only independent predictors of calf cramp were age and hand tremor.
The significance of hand tremor is unclear, said Fiona E. Blyton, BAppSc(Pod), a lecturer in podiatry at the University of Newcastle, Australia, and graduate student at the University of Sydney, who presented the group’s findings at the i-FAB congress.
Hand tremor is a marker of disease severity in patients with CMT, but other such markers were not strongly correlated with calf cramp in the study. Tremor may result from a combination of muscle weakness and impaired stretch reflexes, but strength was not an independent predictor either.
“Both calf cramp and tremor are affected by fatigue. That may be a factor,” Blyton said.
Blyton F, Ryan MM, Ouvrier RA, Burns J. Muscle cramp in pediatric Charcot-Marie-Tooth disease type 1A: prevalence and predictors. Neurology 2011;77(24):2115-2118.