What are the causes of seizures in the elderly?

Causes of Seizures in Old Age

In elderly patients, cerebrovascular disease is the leading cause of new-onset seizures, accounting for the majority of cases, followed by neurodegenerative disorders (particularly Alzheimer's disease), brain tumors, metabolic derangements, and traumatic head injury. 1, 2

Primary Structural Causes

Cerebrovascular Disease (Most Common)

• Stroke and cerebrovascular disease represent the dominant etiology of seizures in the elderly, with both acute ischemic events and chronic vascular changes contributing to seizure risk 1, 2
• Post-stroke seizures can occur acutely or develop as late-onset epilepsy months to years after the vascular event 1
• Small vessel disease and chronic cerebral ischemia create epileptogenic foci over time 2

Neurodegenerative Disorders

• Alzheimer's disease is a major cause of seizures in the elderly, with 5-10% of seizures in patients over 60 years attributed to neurodegenerative dementias 3
• Other dementia types including Lewy body dementia, frontotemporal dementia, and vascular dementia all increase seizure risk 3
• Cerebral amyloid angiopathy, often associated with Alzheimer's disease, independently contributes to seizure development 1

Brain Tumors

• Primary and metastatic brain tumors become increasingly common with age and represent a significant cause of new-onset seizures 1, 2
• Any new seizure in an elderly patient warrants neuroimaging to exclude structural lesions 2

Traumatic Head Injury

• Falls and head trauma are common in the elderly and can cause both acute symptomatic seizures and post-traumatic epilepsy 2, 4

Metabolic and Toxic Causes (Provoked Seizures)

Electrolyte Abnormalities

• Hyponatremia, hypocalcemia, and hypomagnesemia are critical treatable causes that must be identified immediately 5
• Hypocalcemia can trigger seizures at any age, even without prior seizure history, particularly in patients with parathyroid dysfunction 6, 5
• These represent "acute symptomatic seizures" that resolve with correction of the underlying abnormality 5

Glucose Dysregulation

• Nonketotic hyperglycemia is a recognized cause of seizures in elderly diabetic patients 1
• Hypoglycemia must be excluded immediately with point-of-care testing in any seizure patient 7

Uremia and Renal Dysfunction

• Renal failure and uremia can precipitate seizures, particularly common given the high prevalence of chronic kidney disease in the elderly 5, 4

Drug-Induced Seizures

• Medication toxicity and drug interactions are particularly problematic in the elderly due to polypharmacy 1, 8, 4
• Certain medications lower seizure threshold, including tramadol and antipsychotic agents 6, 5
• Anticholinergic medications, sedatives, and multiple cardiovascular drugs can contribute 6, 4
• Non-compliance with antiseizure medications in patients with known epilepsy significantly increases recurrence risk 5

Post-Cardiac Arrest

• Anoxic brain injury following cardiac arrest represents a toxic-metabolic syndrome causing seizures in elderly patients 1

Clinical Presentation Pitfalls

Seizures in the elderly often present atypically, making diagnosis challenging:

• Complex partial seizures are the most common seizure type, frequently presenting with confusion, memory lapses, altered mental status, or behavioral arrest rather than convulsive activity 8, 6
• Prolonged postictal confusion may be misinterpreted as dementia, transient ischemic attack, or primary psychiatric disorder 8, 6
• Nonconvulsive status epilepticus may manifest as recurrent episodes of confusion without obvious motor manifestations 1
• Complete amnesia for the event occurs in up to 40% of elderly patients, complicating history-taking 6

Diagnostic Approach

The workup must systematically exclude reversible causes before attributing seizures to structural disease:

• Immediate point-of-care glucose testing is mandatory 7
• Comprehensive metabolic panel including sodium, calcium, magnesium, and renal function 5
• Neuroimaging (MRI preferred over CT) to identify structural lesions including stroke, tumor, or hemorrhage 2
• EEG has limited utility compared to younger patients but may identify nonconvulsive status or periodic lateralized discharges suggesting stroke 1
• Review all medications for potential seizure-inducing agents or interactions 5, 4

Treatment Principles

For provoked seizures due to metabolic causes, correct the underlying abnormality rather than initiating long-term antiseizure medications 5

• Temporary seizure control with short-acting benzodiazepines if seizures are active and not self-limiting within 5 minutes 5
• Second-generation antiseizure medications are preferred when chronic treatment is needed due to more favorable pharmacokinetic profiles and fewer drug interactions in this age group 3
• Avoid barbiturates, primidone, and benzodiazepines like clobazam due to cognitive effects 1
• Consider that age-related changes in absorption, distribution, metabolism, and excretion require dose adjustments 8, 4