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Altered calcium metabolism in epileptic children on anticonvulsants
Insights
Anticonvulsant drugs in epileptic children can disrupt vitamin D metabolism, leading to low calcium levels. This study highlights the increased vitamin D needs in these patients.
Area of Science:
- Pediatric Endocrinology
- Clinical Pharmacology
- Nutritional Biochemistry
Background:
- Anticonvulsant drugs are widely used in epilepsy management.
- Long-term anticonvulsant therapy has been associated with potential metabolic disturbances.
- Vitamin D deficiency and hypocalcemia have been reported in patients on these medications.
Purpose of the Study:
- To investigate the effects of anticonvulsant drugs on calcium and vitamin D metabolism in epileptic children.
- To assess the prevalence of biochemical abnormalities indicative of altered vitamin D metabolism.
- To explore the relationship between hepatic enzyme induction and serum calcium levels.
Main Methods:
- Survey of 105 epileptic children (aged 10-16 years) on anticonvulsant drugs.
- Measurement of serum calcium and alkaline phosphatase levels.
- Quantification of urinary D-glucaric acid excretion as an index of hepatic enzyme induction.
Main Results:
- Reduced serum calcium observed in 30% of children.
- Elevated serum alkaline phosphatase found in 24% of children.
- Increased urinary D-glucaric acid excretion (indicating liver enzyme induction) in 94% of children, with an inverse correlation to serum calcium levels.
Conclusions:
- Anticonvulsant-induced hepatic enzyme induction significantly alters vitamin D metabolism in epileptic children.
- This alteration leads to increased vitamin D requirements, potentially causing hypocalcemia and osteomalacia.
- Average dietary vitamin D intake in Britain may be insufficient to meet the increased needs of these children.
Abstract:
A survey of 105 epileptic children aged 10-16 years at a residential school who were taking anticonvulsant drugs showed reduced serum calcium levels in 30% and a raised serum alkaline phosphatase in 24%. Urinary D-glucaric acid excretion, a quantitative index of hepatic enzyme induction, was raised in 94% of the children, and statistical analysis showed a significant inverse correlation with the level of serum calcium. These findings give further support for the view that an important factor in the development of the hypocalcaemia and occasional clinical osteomalacia in epileptics on anticonvulsant drugs is an alteration of vitamin-D metabolism in the liver as a result of microsomal enzyme induction. As a consequence there is an increased requirement for vitamin D which may not be met by average intakes in Britain.