Modern Ideas for Treating Epilepsy

Introduction

Epilepsy is a chronic disorder characterized by recurrent unprovoked seizures, and is associated with a variety of medical conditions and neurological diseases. “Antiepileptic medications attempt to treat this chronic seizure propensity, and, by definition, antiepileptogenic drugs aim to prevent the natural history of the epileptic disease” (Raman, Rho, & Cavazos, 2004).

Epileptic seizures are paroxysmal clinical events arising from neuronal hyperexcitability and hypersynchrony of the cerebral cortex, either locally or simultaneously in both hemispheres. A seizure occurs when there is a sudden imbalance between the excitatory and inhibitory inputs to a network of neurons such that there is overall excessive excitability.

The behavioral manifestations of a seizure depend on the area of the area of the cerebral cortex that is involved – directly, in the seizure focus, or indirectly, through recruitment and propagation of this abnormal paroxysmal neuronal activity. Convulsions are defined as seizure that includes motor manifestations such as repeated and rhythmic jerking of the limbs, most often due to involvement of the motor cortex. Anticonvulsant drugs are medications that attempt to compensate for this abnormal cellular hyperexcitability by shifting the delicate balance back toward its normal state.

Treatment for Epilepsy

Prospective population-based studies have demonstrated that 65-70 per cent of patients attain at least a 5-year remission and that half of these will successfully stop treatment. Thus, the “long term prognosis of epilepsy is good for most patients with a short history of seizures” (Appleton, 2001). The question arises as to when treatment should be started and when it can be stopped. Prophylactic treatment may be undertaken in patients with a high prospective risk of epilepsy after head injury and craniotomy for various neurosurgical conditions, although no evidence exists that antiepileptic treatment is effective in such cases.

“The main form of treatment for epilepsy is drugs” (Scambler, 1989). The majority of people can be rendered seizure-free by pharmacological mean, although chronic intractable epilepsy develops in approximately 20 per cent of cases. Occasionally surgery may be appropriate for those who have a single discrete focal abnormality and whose seizures have been unresponsive to drug therapy, but the proportion of those with epilepsy likely to benefit from surgery will probably remain small. Sometimes people can learn to control their seizures by avoiding clear precipitants, for example alcohol or lack of sleep. But the large majority requires anti-convulsant medication, often over a period of many years.

Five drugs are commonly used for the management of partial and grand mal seizures: phenytoin, carbamazepine, sodium valporate, phenobarbitone and primidone. All show similar therapeutic results, but phenobarbitone and primidone tend to be used less because of their sedative effects. Unfortunately, other studies have shown the “high incidence of behavioral side-effects from the treatment” (Lüders, 2001), an important issue when weighing the pros and cons of continuous therapy.

These side-effects occur in 40% of treated children and include irritability, hyperactivity, sleep pattern disturbances, and the possibility of diminished intelligence, but its effectiveness has now been questioned. Mephobarbital has the same side effects as Phenobarbital and phenytoin and carbamazepine do not appear to be effective. The potential role for newer antiepileptic drugs such as lamotrigine and gabapentin is unknown. The Consensus Development Conference on Febrile Seizures attempted to make the best possible recommendations regarding treatment. The panel recommended ‘considering’ continuous anticonvulsant prophylaxis only in the presence of any known high-risk factors. In this basis, only a small percentage of children would require treatment.

References:

Appleton, R. (2001). Epilepsy (4th ed.). Massachusetts, USA: Informa Health Care.

Lüders, H. (2001). Epilepsy: Comprehensive Review and Case Discussions. Great Britain: Informa Health Care.

Raman, S., Rho, J. M., & Cavazos, J. E. (2004). Epilepsy: Scientific Foundations of Clinical Practice. New York – Basel: Informa Health Care.

Scambler, G. (1989). Epilepsy. New Fetter Lane, London: Routledge.