Isaacs' syndrome with muscle hypertrophy reversed by phenytoin therapy

Arch Neurol. 1983 Apr;40(4):241-2. doi: 10.1001/archneur.1983.04050040071012.

Abstract

A 16-year-old boy was seen for severe episodic muscle cramps and generalized myokymia, consistent with Isaacs's syndrome. Bilateral calf hypertrophy (46-cm calf circumference) and ankle areflexia were noted. He was treated with phenytoin sodium, 300 mg/day. Within three months there was marked decrease in myokymia, total relief of cramps, return of ankle reflexes, and 6-cm reduction in calf circumference. We suggest that the excess muscle activity in Isaacs's syndrome may be responsible for the associated phenomena of muscle hypertrophy and areflexia.

Publication types

  • Case Reports

MeSH terms

  • Adolescent
  • Fasciculation / complications
  • Fasciculation / drug therapy
  • Humans
  • Hypertrophy
  • Male
  • Muscle Cramp / complications
  • Muscle Cramp / drug therapy
  • Muscle Rigidity / complications
  • Muscle Rigidity / drug therapy
  • Muscles / pathology
  • Muscular Diseases / drug therapy*
  • Phenytoin / therapeutic use*
  • Syndrome

Substances

  • Phenytoin