Epilepsy in later life

Summary

Epilepsy is most likely to develop in later life. The burden of this disorder on health-care resources will rise further as the world's population continues to age. Making a secure diagnosis can be challenging because the clinical manifestations of seizures and the differential diagnoses and causes of epilepsy can be different in older individuals compared with younger individuals. Obtaining a reliable account of the events for accurate assessment is particularly important in guiding the appropriate choice and interpretation of investigations to arrive at the correct diagnosis. In older age, unique pharmacokinetic and pharmacodynamic changes occur. The use and selection of antiepileptic drugs is often further complicated by the presence of comorbidities, polypharmacy, and concomitant functional impairment, but there is a paucity of high-level clinical evidence on the effects of these factors as well as on the choice of treatment in the elderly. A comprehensive model of care should combine expertise in the diagnosis and treatment of epilepsy with effective assessment and management of the psychosocial effects to improve the prognosis in this vulnerable and poorly studied group of patients.

Introduction

Falls, faints, and “funny turns” (transient neurological attacks comprising focal, non-focal, or mixed neurological symptoms lasting less than 24 h)¹ are all common reasons for elderly people to present to primary care, emergency departments, and specialist hospital services. Some of these individuals, but by no means all, will have epilepsy, which can be a difficult diagnosis to make with certainty. The likelihood of developing seizures correlates better with biological age than with chronological age. Older people are more likely to have comorbidities, as well as functional and cognitive impairment, than younger individuals, which all require recognition, evaluation, and management.² Additionally, age-associated physiological changes can affect the pharmacokinetics and pharmacodynamics of antiepileptic drugs. The situation is exacerbated by a dearth of good clinical trials investigating the choice of treatment for this increasingly common problem.

Because of the range of possible differential diagnoses, older people can be reviewed by general physicians, geriatricians, neurologists, and cardiologists, and so the necessary expertise for appropriate investigation and management is often diluted across a range of clinical disciplines.³ With the continuing ageing of the world's population, the number of older people with epilepsy is set to rise further, placing an increasing burden on health-care resources.

In this Review, we focus on people aged 65 years and older who develop late-onset epilepsy rather than patients who have epilepsy throughout their lives. We place particular emphasis on assessing the clinical clues that are essential for making an accurate diagnosis. We review the pharmacology of antiepileptic drug use in old age, highlighting the most common drug–drug interactions. We summarise the double-blind, randomised trials undertaken in the elderly and list the advantages and disadvantages of each antiepileptic drug in this population. We also review the implications of common comorbidities on the management of late-onset epilepsy. Finally, we propose appropriate models of care and approaches to minimising the effects of epilepsy and its treatment on quality of life in this poorly studied population.