Epilepsy is quite common in old age

Summarized by Robert W. Griffith, MD
June 7, 2000 (Reviewed: December 8, 2002)

The occurrence of epilepsy, or seizures, is more frequent in old age than people imagine. A study done in the United Kingdom¹; showed a rise in the incidence (i.e. the number of new cases in one year per 1,000 people at risk) with age. The overall incidence in the general population was 69 per 1,000, with a low incidence of about 40 per 1,000 during the ages 25 to 55, and then increasing as follows:

	Annual Incidence (per 1,000)
60 - 69 years	76
70 _ 79 years	147
80 years and above	159

The type of epilepsy diagnosed in early life (from childhood through young adulthood) often has no obvious cause, and is therefore called "idiopathic". However, in the over 60s, idiopathic epilepsy accounts for only about 1/4 of new cases. There is usually a triggering cause in the other 3/4 cases, which are called "symptomatic". If the seizure occurs within a week of the triggering event it is regarded as being acute symptomatic, while if it happens more than a week after the precipitating factor it's called a remote symptomatic seizure.

Common causes of acute symptomatic seizures include: stroke (thrombosis or bleeding into the brain tissue), head injury, and disturbances after alcohol withdrawal or the use of some medications.

Remote symptomatic seizures can be caused by a previous stroke, atherosclerosis involving the brain arteries, previous head injury, brain tumor, and Alzheimer's disease.

In over a third of all symptomatic epilepsy in the elderly, atherosclerosis of brain arteries is the underlying cause. Head injury is relatively common in old age, and is more likely to cause seizures than it does in young persons.

Seizures caused by medications are more likely in people are taking several different drugs, if the dose is too high, if the drug is given by injection, or if the person has another illness or illnesses. The list of medications that have been associated with rare cases of seizures is extremely long, and covers nearly all drug classes.

In order to get an accurate diagnosis, the physician needs to take a careful medical history. Disorders that may be confused with symptomatic epilepsy include: irregular heart rhythms, abnormally low or high blood sugar levels (diabetes), a tendency to fainting on standing due to temporary low blood pressure (postural hypotension) and side-effects of medication. Making the correct diagnosis can be greatly helped by an account of the seizure by an eyewitness.

Proper medical investigation of seizures must be extensive: ECG, ultrasound tests of neck arteries, blood pressure measurements sitting, lying and standing (maybe using a tilting table), thyroid gland blood tests, and full routine blood work-up. Depending on the most likely causes of the seizure, magnetic resonance imaging (MRI), computerized tomography (CAT-scan) and/or electroencephalography (EEG) may be ordered by the specialist physician.

The family physician should not delay in referring a seizure patient to a specialist center for appropriate investigations, an accurate and complete diagnosis, and then the most suitable drug treatment. From an early stage, full explanations about all aspects of seizures must be given to the patient, spouse, and children, in order to ensure their cooperation in starting and maintaining the treatment regimen. Life-long therapy may be needed to prevent further seizures, and a support team of advisors (family physician, nurse, health visitor, social worker) can be most helpful in reaching the goal - complete control of seizures, without making life unpleasant for the patient.

There are plenty of anti-epileptic drugs available, but their use in the elderly is complicated because they are sometimes handled differently in the older body - changes in absorption from the intestine, distribution to the brain, and excretion in the urine can all affect the effectiveness and side effects produced by a drug. Unfortunately, good studies of anti-epileptic drugs in older patients are not common, so that it may be advisable to choose a well-tried, older drug. Carbamazepine is safe and effective in the elderly, as is sodium valproate. Oxcarbazepine is a new, "improved" carbamazepine (it has similar effectiveness and side-effects, combined with better handling by the body).

Drugs must be dosed carefully in elderly epileptics - smaller doses are needed than in younger persons, and the rule is "start low, go up slow". With care, complete control of seizures can be achieved in about 70% of cases. Sometimes two drugs can be combined so that improved control can be obtained with lower doses of each drug. If the seizures cannot be controlled with medication, there will be further risk of falls, burns, and fractures.

The biggest problem is often the stigma attached to seizures, whatever the age. Unless the right amount of support is given, subjects can lose self-confidence and become very dependent. This is even worse if the subject has to surrender his/her driving license. However, anxious relatives can be over-protective - its important for the entire care team to try and strike the right balance.

To summarize: epileptic seizures are fairly common in the over 60s, accurate determination of the cause can usually be made in specialist centers, and medication is effective in completely controlling the seizures in about 70% of cases. The outlook is not necessarily bleak for those elders with epilepsy.

The Epilepsy Foundation in the USA has a special section on epilepsy in older persons that contains useful information

Source

• Epilepsy in elderly people LJ. Stephen, MJ. Brodie, Lancet 2000, , vol. 355, pp. 1441--1446

Footnotes
1. Tallis R, Hall G, Craig I, Dean A. How common are epileptic seizures in old age? Age Ageing

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