Understanding Seizures in Older Adults
Seizures in the elderly often present differently than in younger people and are frequently mistaken for other age-related issues like dementia or transient ischemic attacks (TIAs). A seizure is an event of uncontrolled electrical activity in the brain, which can cause a range of symptoms from sudden, uncontrolled movements (convulsive seizures) to brief moments of confusion or staring spells (non-convulsive seizures). While some seizures are isolated incidents, recurrent unprovoked seizures are known as epilepsy.
The Leading Cause: Cerebrovascular Disease
Among all identified causes of new-onset seizures in the elderly, cerebrovascular disease is the most common, accounting for up to 50% of cases.
Stroke
- Ischemic Stroke: Occurs when a blood clot blocks an artery to the brain. The resulting tissue damage (infarction) can become a seizure focus, sometimes years after the initial event.
- Hemorrhagic Stroke: Caused by bleeding in the brain. Blood is highly irritant to brain tissue, and hemorrhagic strokes, particularly those involving the cerebral cortex, have a higher potential to cause seizures.
- Vascular Malformations: Abnormal blood vessels in the brain can also disrupt normal electrical activity and lead to seizures.
Neurodegenerative Diseases
Brain diseases that cause progressive nerve cell damage are a significant risk factor for seizures in older adults.
- Alzheimer's Disease: The risk of seizures is significantly higher in people with Alzheimer's, especially in the later stages of the disease. The damage and buildup of amyloid plaques in the brain disrupt normal neural pathways, increasing seizure risk.
- Dementia with Lewy Bodies and Vascular Dementia: Other forms of dementia also raise the likelihood of seizure activity, and the seizures themselves can be difficult to distinguish from typical dementia symptoms.
Traumatic Brain Injury (TBI)
Head injuries, even seemingly minor ones, can be a potent cause of seizures later in life. Falls are a common cause of head trauma in seniors and can lead to immediate or delayed-onset seizures.
- Chronic Effects: Brain injuries can lead to scarring (gliosis) that disrupts normal brain function, creating a focus for seizures to originate from.
- Subdural Hematomas: These are blood clots that form under the skull and can occur after a head injury. They exert pressure on the brain and can cause seizures.
Brain Tumors
Whether benign or malignant, brain tumors can cause seizures by pressing on or irritating brain tissue. Seizures can sometimes be the first symptom of an undiagnosed tumor. The likelihood of a tumor causing a seizure often depends on its size, location, and rate of growth.
Metabolic and Systemic Conditions
Diseases affecting the entire body can also influence brain function and trigger seizures. Older adults are often more susceptible to these issues due to other health conditions or aging organs.
- Electrolyte Imbalances: Conditions like low sodium (hyponatremia), low calcium, or low magnesium levels can disrupt the electrical balance in the brain. These imbalances are often caused by kidney dysfunction, dehydration, or certain medications.
- Blood Sugar Issues: Both dangerously high (hyperglycemia) and low (hypoglycemia) blood sugar levels can induce seizures, especially in diabetic seniors.
- Infections: Central nervous system infections, such as meningitis or encephalitis, can cause brain inflammation and lead to acute symptomatic seizures.
- Kidney or Liver Failure: When these organs fail, toxins can build up in the blood and affect brain function, lowering the seizure threshold.
Medication and Substance Withdrawal
Seniors typically take multiple medications, increasing the risk of adverse drug reactions or interactions that can trigger seizures.
- Drug Side Effects: Medications like certain antidepressants, antipsychotics, or some antibiotics can lower the seizure threshold.
- Drug Interactions: The aging liver and kidneys metabolize drugs differently, which can lead to toxic levels of medication in the bloodstream.
- Alcohol Withdrawal: In seniors with a history of alcohol use, sudden cessation can precipitate dangerous withdrawal seizures.
Seizure Mimics in the Elderly
Diagnosing seizures in the elderly is challenging because their symptoms can overlap with other conditions. This often leads to misdiagnosis, delaying appropriate treatment. Common seizure mimics include:
- Transient Ischemic Attacks (TIAs): Often called 'mini-strokes,' TIAs cause temporary, stroke-like symptoms, which can sometimes be confused with focal seizures.
- Syncope (Fainting): A sudden loss of consciousness due to reduced blood flow to the brain can sometimes be accompanied by brief, convulsive movements, known as convulsive syncope.
- Cardiac Arrhythmias: Irregular heart rhythms can reduce oxygen flow to the brain, causing confusion or blackouts that resemble seizures.
- Sleep Disorders: Conditions like REM sleep behavior disorder can cause violent thrashing or limb movements during sleep, which can be mistaken for nocturnal seizures.
When to Seek Medical Attention
If an elderly person has a suspected seizure, it is crucial to seek immediate medical help. An accurate diagnosis often requires a detailed medical history, witness accounts, a physical exam, and diagnostic tests such as an EEG and brain imaging (MRI or CT). Caregivers should track and document episodes, noting the duration, symptoms, and any potential triggers. This information is invaluable for a neurologist.
Comparison of Common Causes of New-Onset Seizures in the Elderly
| Cause | Mechanism | Typical Presentation | Associated Conditions |
|---|---|---|---|
| Stroke | Damage to brain tissue disrupts electrical signals | Focal seizures more common; may occur years after the event | Hypertension, heart disease, diabetes |
| Dementia | Neurodegeneration and nerve cell loss lowers seizure threshold | Subtle confusion, staring spells, or motor symptoms | Alzheimer's, vascular dementia, Lewy body disease |
| Brain Tumors | Pressure or irritation from mass disrupts brain activity | Can be the first symptom; varies with tumor location | Benign or malignant tumors of the brain |
| Metabolic Issues | Imbalances in electrolytes or glucose disrupt brain function | Seizures can resolve once the underlying imbalance is corrected | Kidney disease, diabetes, dehydration |
| Medication Effects | Certain drugs or withdrawals alter brain chemistry | Seizure onset can coincide with starting or stopping medication | Polypharmacy, alcohol abuse |
Conclusion
While a seizure in an elderly person can be frightening, understanding the underlying causes is the first step toward effective management and treatment. The high incidence of seizures in this population is often a result of coexisting age-related health issues, including strokes, neurodegenerative diseases, and medication complications. A proper diagnosis requires careful observation and medical evaluation, as symptoms can be subtle and easily confused with other conditions. By working closely with healthcare professionals and focusing on managing underlying conditions, it is possible to mitigate risks and improve the overall well-being of seniors living with seizures. For more information on geriatric health, consult an authoritative source like the National Institute on Aging: National Institute on Aging: Health & Aging.
