Alterations in the carnitine metabolism in epileptic children treated with valproic acid

L-Carnitine supplementation to reverse hyperammonemia in a patient undergoing chronic valproic acid treatment: A case report

Valproic acid is a broad-spectrum anticonvulsant that has also gained attention in the psychiatric setting. With respect to safety, valproic acid may induce a seemingly rare condition, hyperammonemia, which can induce a wide variety of symptoms ranging from irritability to coma. The proposed mechanism of hyperammonemia involves depletion of carnitine and overproduction of a toxic metabolite, 4-en-valproic acid, both of which impair the urea cycle and thus ammonia elimination. Carnitine is a commonly used antidote for acute intoxication of valproic acid, but is not a therapeutic option for management of chronic adults with adverse effects related to valproic acid. We herein report a case involving a woman with epilepsy who developed hyperammonemia after a change in her anticonvulsant therapy. She reported increased seizures and gastrointestinal disturbances. Her ammonia, valproic acid, 4-en-valproic acid, and carnitine levels were monitored. Her ammonia level was elevated and her carnitine level was at the inferior limit of the population range. She was supplemented with carnitine at 1 g/day. After 1 month, her ammonia level decreased, her carnitine level increased, and her seizures were better controlled. Carnitine supplementation was useful for reversal of her hyperammonemia, allowing her to continue valproic acid for seizure control.

Serum and muscle carnitine levels in epileptic children receiving sodium valproate

The purpose of this study was to determine whether children with epilepsy undergoing valproate therapy and who are otherwise healthy have lower levels of serum and muscle carnitine. A total of 50 patients with epilepsy, 3 to 14 years of age, who were treated solely with valproate and free of abnormal neurologic findings or nutritional problems were selected. The control group consisted of 30 healthy children. The total carnitine levels in serum were 28.1 +/- 10.3 and 55.6 +/-7.3 microg/mL, and the free carnitine levels in serum were 16.5 +/-10.2 and 44.6 +/-7.3 microg/mL, the total carnitine levels in muscle were 12.1 +/- 1.8 and 45.3 +/- 5.9 micromol/g noncollagen protein and the free carnitine levels in muscle were 5.6 +/- 1.6 and 39.3 +/- 6.0 micromol/g noncollagen protein in the valproic acid-treated and control groups, respectively (P < .05). In conclusion, valproate monotherapy depletes both muscle and serum carnitine levels in otherwise healthy epileptic children.

Plasma free carnitine in epilepsy children, adolescents and young adults treated with old and new antiepileptic drugs with or without ketogenic diet

This study was performed to evaluate carnitine deficiency in a large series of epilepsy children and adolescents treated with old and new antiepileptic drugs with or without ketogenic diet. Plasma free carnitine was determined in 164 epilepsy patients aged between 7 months and 30 years (mean 10.8 years) treated for a mean period of 7.5 years (range 1 month-26 years) with old and new antiepileptic drugs as mono or add-on therapy. In 16 patients on topiramate or lamotrigine and in 11 on ketogenic diet, plasma free carnitine was prospectively evaluated before starting treatment and after 3 and 12 months, respectively. Overall, low plasma levels of free carnitine were found in 41 patients (25%); by single subgroups, 32 out of 84 patients (38%) taking valproic acid and 13 of 54 (24%) on carbamazepine, both as monotherapy or in combination, showed low free carnitine levels. A higher though not statistically significant risk of hypocarnitinemia resulted to be linked to polytherapy (31.5%) versus monotherapy (17.3%) (P=.0573). Female sex, psychomotor or mental retardation and abnormal neurological examination appeared to be significantly related with hypocarnitinemia, as well. As to monotherapy, valproic acid was associated with a higher risk of hypocarnitinemia (27.3%) compared with carbamazepine group (14.3%). Neither one of the patients on topiramate (10), lamotrigine (5) or ketogenic diet (11) developed hypocarnitinemia during the first 12 months of treatment. Carnitine deficiency is not uncommon among epilepsy children and adolescents and is mainly linked to valproate therapy; further studies are needed to better understand the clinical significance of serum carnitine decline.

Down syndrome and epilepsy: a nutritional connection?

Non-Asian individuals with Down syndrome are much more likely to develop epileptic seizure disorders than individuals without Down syndrome. Examination of nutrient and metabolite levels in patients with these two seemingly disparate disorders reveals numerous similarities. Compared to individuals without these disorders, individuals with Down syndrome and individuals with seizures may have lower levels of vitamin A, vitamin B1, folate, vitamin B12, vitamin C, magnesium, manganese, selenium, zinc, carnitine, carnosine, choline, and possibly serine. Excesses of copper, cysteine, phenylalanine, and superoxide dismutase are also sometimes encountered in both disorders. In addition to common nutritional lower levels and excesses, disorders of metabolism involving vitamin B6, vitamin D, calcium, and tryptophan may play a common role. This paper hypothesizes that nutritional factors may account for the high joint occurrence of these conditions. Further examination of these data may provide insights into nutritional, metabolic and pharmacological treatments for both conditions.

Seizures in the adult intensive care unit

Seizures are a common occurrence in the intensive care unit (ICU). The presentation of seizures is usually as focal or generalized motor convulsions, but other seizure types may occur. Etiologies of the seizures are typically secondary either to primary neurologic pathology or a consequence of critical illness and clinical management. Particularly important as precipitants of seizures are hypoxia/ischemia, drug toxicity, and metabolic abnormalities. It is important to properly diagnose the seizure type and its cause to ensure appropriate therapy. Most seizures occur singly, and recurrence is usually prevented with initiation of anticonvulsant therapy. However, status epilepticus may develop, which requires emergent treatment before irreversible brain injury occurs. Treatment with anticonvulsants is not without untoward risks, however, and primary toxicities of these agents is reviewed. After traumatic head injury, brain surgery, or cerebrovascular accidents, many patients are at risk for seizures. Current data on the benefits of prophylactic therapy for such patients is also reviewed.