Epilepsy

Since many older people live alone, there may be an inadequate history and older people may present with a history of recurrent unexplained falls or of being found on the floor. The vast majority of seizures in old age are either partial seizures with, for example, focal motor events such as recurrent jerking of an arm or leg, or secondary generalized seizure that may present either with disturbances of higher level function as in complex partial seizures or with convulsive movements. The list of conditions that may be confused with epilepsy is very long and includes: fainting; low blood sugar; transient ischaemic attacks; recurrent paroxysmal behavioral disturbances, such as clapping or calling out, secondary to dementia; drop attacks and other nonepileptic causes of falls; transient global amnesia; and nonepileptic attack disorder or psychogenic attacks. Conversely, there is an equally long list of conditions that are genuinely epileptic but may be thought to be nonepileptic; partial motor status epilepticus (e.g., persistent involuntary movement of an arm or leg) may be thought to be an extrapyramidal movement disorder such as Parkinson's disease; sensory epilepsy may be thought to be a transient ischaemic attack; complex partial seizures in which a patient may stare or call out can be confused with psychoses; atonic seizures can be confused with drop attacks or hysteria; and Todd's palsy (transient weakness) following a generalized seizure can be confused with a new stroke or a transient ischaemic attack.

The biggest challenge in elderly epileptology is determining whether or not the patient's events are seizures or fainting (syncope). Differentiating the two conditions may be extremely difficult in the absence of an eyewitness report. Moreover, the usual features that differentiate the two conditions may not apply to older people. For example, whereas syncope is not usually associated with either incontinence (loss of bladder and/or bowel control) or post-event confusion, an elderly person who is already incontinent or has background confusion may be incontinent or confused in association with a syncope attack. Even so, the history remains the most powerful diagnostic tool. Investigations will be guided by the history and the findings on examination. The EEG will rarely be useful in making a diagnosis of epilepsy and certainly should not be used to make up for the shortfalls in history taking. The indications for neuroimaging are not well defined and depend at least in part on the availability of radiological services. Strong indications for neuroimaging include unexplained focal neurological signs, progressive or new neurological symptoms, especially those of raised intracranial pressure, progressive or new neurological signs or poor control of fits not attributable to poor compliance, or continued exposure to precipitants such as alcohol.

The most common cause of seizures in old age is cerebrovascular disease: seizures may be a harbinger of future manifestations of cerebrovascular disease; late onset seizures are associated with a higher level of occult cerebral ischaemia; and overt strokes may trigger seizures either acutely or subsequently. Any patient who develops a seizure for the first time in old age when there was no obvious cause should be thoroughly investigated for cardiovascular risk factors and possibly placed on low dose aspirin, so long as there is no contraindication. Other cerebral causes of seizures include tumor, which may account for 10 to 15 percent of elderly onset cases. However, the proportion of these cases in which seizure is the only manifestation and the proportion in which any underlying tumor found is benign and/or resectable is not known. Seizures may occur in nonvascular cerebral degenerative disease, such as Alzheimer's disease. Non-cerebral causes of seizures include those which are secondary to cerebral anoxia as in prolonged syncopal attacks due, for example, to cardiac arythymias. Seizures may also be triggered by a wide variety of drugs that have proconvulsant side effects, notably tricyclic antidepressants, phenothiazines, and aminophylline. The role of alcohol in triggering seizures in older people or in interfering with control must not be forgotten.