Epilepsy in the Elderly

Ann Johnston; Phil EM Smith

Disclosures

Expert Rev Neurother. 2010;10(12):1899-1910. 

In This Article

Expert Commentary

Epilepsy in the elderly is common, although the figures given by large epidemiological studies are likely to be an overestimate owing to the inherent difficulties in the clinical diagnosis of epilepsy in the elderly. Expertise and clinical acumen are needed to exclude the epilepsy mimics and to take account of the multiple comorbidities and polypharmacy of old age.

Epilepsy in the elderly, as in younger patients, is a clinical diagnosis, reliant upon the assimilation and interpretation of the patient's clinical narrative and, whenever possible, that of an eye witness. Eye-witnessed accounts are often not available, as elderly people are less frequently employed, less socially active and often live alone. In the elderly, the challenge of an accurate diagnosis is complicated by comorbidities and polypharmacy of old age and also by atypical seizure presentations, often with vague auras or dizziness. Clinicians need a greater awareness of the many causes of transient loss of consciousness in the elderly and particularly of atypical presentations.

The clinical history and the investigation of epilepsy in the elderly should attempt to identify an underlying etiology, although this cannot definitely be identified in up to 50% of patients. Stroke is the leading cause of new-onset epilepsy after the age of 65 years and accounts for 50–75% of cases of epilepsy where a cause is found. A 12-lead ECG is essential in patients presenting with a 'blackout' or 'funny turn', in order to diagnose, risk stratify and refer urgently those with (often not previously recognised) cardiac disease. Brain imaging (preferably MRI) in the elderly is essential in new-onset focal seizures. However, normal age-related changes (white matter dots and cerebral atrophy) must not be overinterpreted. Interictal EEG is much less diagnostically helpful in the elderly compared with younger people and again must be interpreted with caution, owing to often nonspecific findings of slow waves.

The assessment of elderly patients with epilepsy (as with any condition) should take account of the chronological rather than biological age. Epilepsy management should aim for seizure freedom with minimal side effects and with maintenance of a normal lifestyle. NICE has published comprehensive guidelines on epilepsy but made no specific recommendations for older people. The Scottish Intercollegiate Guidelines Network developed epilepsy management guidance for adults of all ages, and recommended lamotrigine for elderly people because of its favorable adverse-event profile and few drug interactions (note that lamotrigine has to be increased slowly because of the risk of rash, and so serum levels, and hence seizure control, may not be optimal for several weeks). Valproate was recommended for primary generalized seizures, although these are rare in the elderly. It seems reasonable to consider some newer AEDs, such as levetiracetam, given its inert metabolites and lack of drug and adverse reactions. The likelihood of stroke being the cause of new-onset epilepsy in the elderly has also been considered sufficiently high to justify prescribing an antihypertensive and a statin to elderly patients presenting with unprovoked seizures.

The key to minimizing side effects of AEDs is to start at a low dose and titrate gradually to an effective dose. AED side effects, such as cognitive disturbance, dizziness, somnolence and osteoporosis, have greater implications to the elderly than to younger patients. Somnolence and cognitive disturbance are common AED side effects and these can contribute to falls and injuries, even if not caused by seizures. Osteoporosis is important in elderly patients and certain AEDs, such as phenytoin, phenobarbital and carbamazepine, may reduce vitamin D by enzyme induction and so can substantially increase an elderly patient's risk of fracture. There are no generally accepted guidelines for bone management in epilepsy patients. However it seems reasonable for at-risk groups – such as the frail elderly taking enzyme-inducing AEDs – to be prescribed prophylactic vitamin D and calcium.

Epilepsy management in the elderly is about more than just seizure control and, as in younger people, should cover other aspects there are often more important to the patient, such as associated comorbidities, quality of life issues, medication side effects, driving eligibility, social stigmas, taboos and discrimination. For these reasons, a multidisciplinary team approach to epilepsy management in the elderly may offer the best health outcomes.

Elderly patients with first suspected seizures need access to a service where neurologists work closely with care of the elderly physicians and cardiologists. In those presenting with a first suspected seizure, rapid investigation and appropriate management can be optimized. Those with established epilepsy require access and follow-up in specialist services.

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