eMedicine Specialties > Neurology > Pediatric Neurology
Myoclonic Epilepsy Beginning in Infancy or Early Childhood: Treatment & Medication
Updated: Aug 21, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
Treatment
Medical Care
- The mainstay of medical therapy for myoclonic epilepsy is sodium valproate, ethosuximide, or benzodiazepines.6
- Patients with the benign form respond well to valproate or ethosuximide.
- Either one of the drugs may be started; if both fail independently, they may be combined.
- The duration of treatment is tailored on an individual basis but is usually approximately 5 years.
- Second-line medications include clonazepam, methsuximide, acetazolamide, and sulthiame.
- Treatment for the more severe myoclonic epilepsies is more difficult and is essentially the same as for Lennox-Gastaut syndrome.
- All types of antiepileptic medications may be tried, with the exception of vigabatrin and carbamazepine, which actually may worsen the seizures.
- Combination therapy with valproate and benzodiazepines may be the best alternative.
- Adrenocorticotropic hormone (ACTH), steroids, and immunoglobulins have been tried but have shown no significant benefit.
Consultations
Patients should be evaluated by a pediatric neurologist. If dysmorphic features are present, a genetic evaluation may be useful.
Diet
The ketogenic diet may be useful in caring for children with particularly refractory epilepsy. This should be instituted only on an inpatient basis, paying particular attention to the possibility of dehydration.
Activity
Caution should be used in children with drop attacks, as they may fall and injure themselves. A helmet can be protective. Routine seizure precautions are also applicable.
Medication
The goals of pharmacotherapy are to reduce morbidity and prevent complications.6
Antiepileptic agents
Patients with the benign form respond very well to valproate or ethosuximide.
Valproic acid (Depakote)
Chemically unrelated to other drugs that treat seizure disorders. Although mechanism of action not established, activity may be related to increased brain levels of GABA, or enhanced GABA action. Valproate also may potentiate postsynaptic GABA responses, affect potassium channels, or have direct membrane-stabilizing effect.
Use in young children (younger than 2 y) associated with risk of hepatotoxicity. This risk estimated to occur in fewer than 1 in 250 children treated.
Adult
Initial: 5-15 mg/kg/d PO
Maintenance: 15-25 mg/kg/d PO
Pediatric
Initial: 10-30 mg/kg/d PO
Maintenance: 30 mg/kg/d PO
Cimetidine, salicylates, felbamate, and erythromycin may increase toxicity; rifampin may reduce levels significantly; in children, salicylates cause decreases in protein binding and metabolism of valproate; may result in variable changes of carbamazepine concentrations with possible loss of seizure control; may increase diazepam and ethosuximide toxicity (monitor closely); may increase phenobarbital and phenytoin levels while either may decrease valproate levels; may displace warfarin from protein-binding sites (monitor coagulation tests); may increase zidovudine levels in HIV-seropositive patients
Documented hypersensitivity; hepatic disease/dysfunction
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Thrombocytopenia and abnormal coagulation parameters have occurred; risk of thrombocytopenia increases significantly at total trough valproate plasma concentrations >110 mcg/mL in females and >135 mcg/mL in males; at periodic intervals and prior to surgery, determine platelet count and bleeding time before initiating therapy; reduce dose or discontinue therapy if hemorrhage, bruising, or hemostasis/coagulation disorder occur; hyperammonemia may occur; monitor patients closely for appearance of malaise, weakness, facial edema, anorexia, jaundice, and vomiting
Ethosuximide (Zarontin)
Mechanism of action based on reducing current in T-type calcium channels found on thalamic neurons. Spike-and-wave pattern during petit mal seizures thought to be initiated in thalamocortical relays by activation of these channels. Used as adjunctive medication to valproic acid if that medication has failed to control seizures.
Adult
500-2000 g/d PO
Pediatric
15-40 mg/kg/d PO
Phenytoin, carbamazepine, primidone, and phenobarbital may decrease effects; isoniazid may inhibit hepatic metabolism, increasing toxicity
Documented hypersensitivity; blood dyscrasias; renal or hepatic disease
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Blood dyscrasias, which may be fatal, may occur (monitor CBC); caution in hepatic or renal disease; abrupt withdrawal may precipitate absence status
Clonazepam (Klonopin)
Suppresses muscle contractions by facilitating inhibitory GABA neurotransmission and other inhibitory transmitters. Useful in immediate control of seizures, although often associated with relatively rapid loss of efficacy against seizures.
Adult
0.05-0.2 mg/kg/d PO
Pediatric
Administer as in adults
Phenytoin and barbiturates may reduce effects; CNS depressants increase toxicity
Documented hypersensitivity; severe liver disease; acute narrow-angle glaucoma
Pregnancy
C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus
Precautions
Caution in chronic respiratory disease or impaired renal function; withdrawal symptoms can result from abrupt discontinuation of medication
More on Myoclonic Epilepsy Beginning in Infancy or Early Childhood |
| Overview: Myoclonic Epilepsy Beginning in Infancy or Early Childhood |
| Differential Diagnoses & Workup: Myoclonic Epilepsy Beginning in Infancy or Early Childhood |
 Treatment & Medication: Myoclonic Epilepsy Beginning in Infancy or Early Childhood |
| Follow-up: Myoclonic Epilepsy Beginning in Infancy or Early Childhood |
| References |
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References
Zara F, Gennaro E, Stabile M, Carbone I, Malacarne M, Majello L, et al. Mapping of a locus for a familial autosomal recessive idiopathic myoclonic epilepsy of infancy to chromosome 16p13. Am J Hum Genet. May 2000;66(5):1552-7. [Medline].
Wang PJ, Lee WT, Hwu WL, Young C, Yau KI, Shen YZ. The controversy regarding diagnostic criteria for early myoclonic encephalopathy. Brain Dev. Oct 1998;20(7):530-5. [Medline].
Aicardi J. Myoclonic epilepsies of infancy and childhood. Adv Neurol. 1986;43:11-31. [Medline].
Sheth RD. Electroencephalogram in developmental delay: specific electroclinical syndromes. Semin Pediatr Neurol. Mar 1998;5(1):45-51. [Medline].
Doose H, Lunau H, Castiglione E, Waltz S. Severe idiopathic generalized epilepsy of infancy with generalized tonic-clonic seizures. Neuropediatrics. Oct 1998;29(5):229-38. [Medline].
Wallace SJ. Myoclonus and epilepsy in childhood: a review of treatment with valproate, ethosuximide, lamotrigine and zonisamide. Epilepsy Res. Jan 1998;29(2):147-54. [Medline].
Lombroso CT. Early myoclonic encephalopathy, early infantile epileptic encephalopathy, and benign and severe infantile myoclonic epilepsies: a critical review and personal contributions. J Clin Neurophysiol. Jul 1990;7(3):380-408. [Medline].
Shahwan A, Farrell M, Delanty N. Progressive myoclonic epilepsies: a review of genetic and therapeutic aspects. Lancet Neurol. Apr 2005;4(4):239-48. [Medline].
Further Reading
Keywords
myoclonic epilepsy, myoclonic seizures, astatic myoclonic epilepsy of Doose, benign infantile myoclonic epilepsy, infantile spasms, progressive myoclonic epilepsy, severe infantile myoclonic epilepsy
