Chapter 56: Surgery for Catastrophic Epilepsies: When and Why?

INTRODUCTION

The term catastrophic epilepsy is applied to children with epilepsy who present with some of the following characteristics:

• Urgent need for treatments.

• Onset in early life.

• There is commonly a major loss of cognitive and behavioral functions, which may be profound.

• There is relatively high mortality.

The combination of sudden onset of seizures and massive regression may resemble an acute brain illness and be mistakenly diagnosed as having "encephalitis." Careful review of the history and investigations should show no positive evidence of parenchymal brain disease and the time course may show fluctuations of function relating to seizure severity even if only over a few weeks.

INDICATIONS FOR SURGERY

The term "catastrophic" has been particularly useful in the context of potentially surgically treatable epilepsies.^1,2 The term implies that seizures per se are causing the deterioration, that is, it is an epileptic encephalopathy as defined in the 2001 ILAE epilepsy classification³ and that early intervention for seizures, be it medical or surgical, may arrest or even reverse some of the loss of skills.⁴ It may, however, be difficult to accurately define the contribution of seizures and causative pathological process, which serves as the basis for case selection and management (Fig. 56–1). The imperatives for surgical intervention are:

• The seizure disorder is caused by a focal abnormality, which may be a discrete or hemispheric lesion.

• Resistance to antiepileptic drug (AED) treatment.

• The lesion is resectable with minimal hazard.

• The chances of natural remission are small.

Catastrophic epilepsy surgery should be performed as early as possible with the aim of allowing the child as many seizure-free years of childhood as possible; the ultimate goal is to minimize cognitive and behavioral impairments. Too often, several years pass between the early presentation with epilepsy and surgery.⁵ It is common to successfully surgically treat children of 8 years or more who have presented in the first year of life with infantile spasms, but it may take several years to recognize that the child has a surgically treatable epilepsy.

The reasons for delaying surgical intervention are numerous and include lack of awareness that the child has a surgically treatable epilepsy or temporary seizure remission. There is also a tendency to unsuccessfully try multiple AEDs.⁶ In some cases, accurate localization of the epileptogenic zone may be challenging in the first year of life.

Many children with lesional epilepsy who present with infantile spasms rapidly regress at seizure onset and remain delayed, even with successful treatment. The correlates of epileptic encephalopathy are poorly understood but clearly involve cognitive and behavioral network dysfunction distant from the lesion. Early regression is easily overlooked and a careful history and ...