Phenytoin induced vitamin D deficiency presenting as proximal muscle weakness

Indian Pediatr. 2010 Jul;47(7):624-5. doi: 10.1007/s13312-010-0121-3.

Abstract

A 6-year-old girl presented with proximal muscle weakness of lower limbs. She was receiving phenytoin for epilepsy for 2 years. Serum phenytoin level was within therapeutic range. Serum 25(OH) vitamin D was low (5 ng/mL) and serum parathyroid hormone level was high. After administration of oral vitamin D, muscle weakness improved and vitamin D level increased to 39.11 ng/mL. Proximal muscle weakness due to vitamin D deficiency following phenytoin intake is rare in children.

MeSH terms

  • Child
  • Epilepsy / drug therapy
  • Female
  • Gait / drug effects
  • Humans
  • Hyperparathyroidism, Secondary
  • Muscle Weakness / chemically induced*
  • Muscle Weakness / drug therapy
  • Muscle Weakness / physiopathology
  • Phenytoin* / adverse effects
  • Phenytoin* / pharmacology
  • Phenytoin* / therapeutic use
  • Vitamin D / administration & dosage
  • Vitamin D / therapeutic use
  • Vitamin D Deficiency* / chemically induced
  • Vitamin D Deficiency* / physiopathology

Substances

  • Vitamin D
  • Phenytoin