Differential Diagnosis for New Onset Seizures in a 90-Year-Old
Single Most Likely Diagnosis
- Cerebrovascular Disease (Stroke): The most common cause of new onset seizures in the elderly is cerebrovascular disease, including ischemic and hemorrhagic strokes. The risk of stroke increases with age, and seizures can occur as a complication of a stroke.
Other Likely Diagnoses
- Dementia: Conditions like Alzheimer's disease can lead to seizures, especially in advanced stages. The degeneration of brain tissue can disrupt normal electrical activity, leading to seizures.
- Metabolic Disorders: Electrolyte imbalances (such as hyponatremia, hypernatremia, hypocalcemia, or hypomagnesemia), hypoglycemia, and hyperglycemia can cause seizures in elderly patients. These conditions are more common in this age group due to various factors, including medication side effects and decreased renal function.
- Infections: Infections such as meningitis, encephalitis, or sepsis can cause seizures. Elderly individuals are more susceptible to infections due to decreased immune function.
- Medication Side Effects: Many medications, including certain antibiotics, antihistamines, and antidepressants, can lower the seizure threshold and cause seizures, especially in elderly patients who may be more sensitive to medication side effects.
Do Not Miss Diagnoses
- Subdural Hematoma: A subdural hematoma, which can occur after a fall, is a critical diagnosis to consider. Even minor trauma can lead to significant bleeding in the elderly due to brain atrophy and increased fragility of bridging veins.
- Brain Tumors: Although less common, brain tumors (primary or metastatic) can cause seizures. Given the potential for significant morbidity and mortality, it's crucial not to miss this diagnosis.
- Central Nervous System Vasculitis: This is a rare but potentially treatable condition that can cause seizures among other neurological symptoms. Missing this diagnosis could lead to significant morbidity.
Rare Diagnoses
- Creutzfeldt-Jakob Disease: A rare, degenerative, fatal brain disorder that can cause seizures among other neurological symptoms.
- Hashimoto's Encephalopathy: A rare condition associated with autoimmune thyroiditis that can cause seizures and other neurological symptoms.
- Paraneoplastic Syndromes: Rare neurological disorders caused by the immune response to a cancer, which can lead to seizures.