INTRODUCTION

Epilepsy in elderly patients, compared with the younger adult population, differs in etiology, clinical presentation, and prognosis as well as Challenges in the pharmacologic treatments. Epilepsy is considered as one of the most common diseases among people over the age of 75 years, nevertheless it is mostly misdiagnosed as mental changes of uncertain origin, confusion, syncope (fainting), memory disorders, or vertigo.^1,2,3,

Epilepsy in elderly persons has been subdivided according to age into the young old “65-74 years” old “75-84 years “ and old-old over the age of 85 year. Anyhow, in this age extremity, it is very common to find comorbidities with epilepsy presentation.^4,5

The advancement of neuroimaging scanning locates EEG in the second row tool to determine the underlying etiology of epilepsy in elderly peoples. In addition, EEG abnormalities in healthy elderly individuals are common and the patterns of EEG in epileptic elderly are often not the classic and obvious patterns.^6,7

The common EEG findings among old patients are very subtle, blunted or sharply contoured rhythms or simple rhythmic slow wave activity that comes and go.

The initial EEG is usually demonstrating epileptiform discharge in 56%; while repeated EEG is recommended in most literatures because it captures characteristic abnormalities in more than 80%.⁸ In various studies four EEGs yield epileptiform abnormalities in more than 90%.⁹

The incidence of epilepsy in elderly is double that of 40-59 years old. It continues to increase for each subgroup. In the company of those who older than 85 years, the incidence becomes three times higher than those aged 65 to 69 years. Therefore, in near future, epilepsy in elderly will be a crucial problem because the health care improvement and long life.^3,6

The current study is designed to report the crucial roles of careful history taking, clinical semiology, EEG changes and MRI findings in determination the causes of epilepsy in old age people.

PATIENTS AND METHODS

The current study enrolled forty four seniors who had history of different forms of epilepsy. Twenty eight (63.6%) patients were males and sixteen (36.4%) were females. Their ages ranged from 65-88 years with a mean age of 76.6±2.7 years.

All patients were enrolled from outpatient clinics of neurology department, at Mansoura University Hospital during the period from Jan-2008 to Dec-2009.

After a detailed history and clinical examination, routine laboratory tests were done for all patients; the investigations included complete blood count, serum electrolyte, calcium, magnesium, phosphorus, blood urea, nitrogen, serum creatinine, fasting blood glucose, erythrocyte sedimentation rate, liver function tests and toxicology screen.

In addition, all patients had initial MRI (General Electric 1.5 Tesla medical system) of the brain (T1, T2 and FLAIR weighted images), interictal electroencephalography (EEG) (Nihon Kohden 16–channel EEG machine). What’s more, some patients were scheduled for lumber puncture (LP) in certain confused or obscured etiology of their seizures onset.

Statistical Analysis:

The demographic, clinical, and technical data were collected using a ‘data collection form’ and entered into a computerized database before statistical analysis. Continuous variables were compared using analysis of variance for repeated measures. P-value less than 0.05 was considered statistically significant. All data were expressed as mean ± standard deviation (SD) or patient’s number (n) and percentage (%) as appropriate.

RESULTS

Ten out of forty four patients (22.7%) were young old (65-74 years) and 27.3% were old (75-84 years) and 50% were oldest old (85 years or more) (Table 1).

Risk factors that documented in the current study (Table 2) were diabetes mellitus (47.7%), hypertension (38.6%), ischemic heart disease (22.7%), drug intake (15.9%), sleep disorders (13.6%), renal impairment (6.8%), hepatic impairment (6.8%), past history of seizures (4.5%) and migraine (4.5%).

The complex partial without aura in was the most common form of epilepsy (45.5%) that documented in the existing study followed by focal with secondary generalization (31.9%), complex partial with aura (11.4%), generalized tonic clonic (4.5%), status epilepticus (4.5%) then simple partial (2.2%) (Table 3).

Twelve patients (27.2%) out of 44 patients had normal initial EEG but with repeated EEG only 18% of them yield normal EEG pattern. Focal epileptic discharges with secondary generalization were recorded in 14 patients (31.3%) as well other forms of epileptiform discharges were identified (Table 4 and Figure 1).

Cerebral infarction as a main cause of epilepsy was confirmed by CT and MRI brain in 18.1% of patients, 6.8 % cerebral hemorrhage, 4.5% meningioma, 9.2% glioma and metastasis in 11.3%  of enrolled patients (Table 5 and Figures 2-7).

Table 1. Epilepsy patients’ subgroups according to age.

Table 2. Risk factors of epilepsy in elderly.

Table 3. Semiology of seizures in elderly epileptic patients.

Table 4. EEG changes among enrolled patients with epilepsy.

Table 5. CT and MRI findings among enrolled patients with epilepsy.

Early: early seizures,   Late: late seizures

DISCUSSION

It is suggested that epilepsy in elder people is not so much a disease as a common pathway of various diseases. Age has crucial role in epileptogenesis effect via loss of postsynaptic glutamate receptors, decreased cholinergic transmission, increased gap junctions and changes in calcium dependent pathways that lead to impair neuronal function and increased seizures risk.¹⁰

The incidence of epilepsy in elderly is double that of people aged 40 to 59 years.¹¹ This harmonized with the current results, as the frequency of epilepsy in patients aged 85 or more was nearly triple than patients who aged 65 to 74 years.

Diabetes mellitus (47.7%) was the most common risk factor among enrolled patients, followed by hypertension (38.6%) and ischemic heart disease (22.7%) that correlated with many studies.^12,13

In existing study, complex partial seizures were the most common seizures semiology in particular CPS without aura (45.5%) followed by secondary generalization (31.9%). De La Courte et al.³ mentioned 60.2% of cases had complex partial seizures followed by secondary generalized.

In present study, initial EEG was normal in 12 patients (27.2%) that decreased to 18% when EEGs were performed up to four times for the same patients.^8,9

Cerebrovascular disease is a common leading cause of elderly epilepsy. In existing study, the percentage of cerebral infarction, hemorrhagic infarction, cerebral hemorrhage and hypertensive arteriosclerotic were 18.1%, 6.8%, 6.8% and 6.8% consecutively.^13-16

Post traumatic cerebral contusion seizures were reported in 2.3%, Intracerebral hemorrhage in 6.8%, and subdural hematoma 6.8%.^20-22

Primary or metastatic lesions are important causes of seizure activity; about 10.7% of older age group is related to cancer, not necessarily involving the nervous system.^23,24 In current study meningioma was reported in 4.5%, 9.2% Glioma and 11.3% brain metastasis.

Central Nervous System Infection was confirmed in only two cases (4.6%), one patient had meningitis and the other one had meningoencephalitis.^25-27

In conclusion: Full history taking, clinical examination, repeated long term EEG and neuroimaging studies are essential tools for accurate and early diagnosis of elderly epilepsy.

[Disclosure: Authors report no conflicts of interest]

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