Doctor's Notes on Stroke-Related Dementia
A stroke occurs when part of the brain does not receive enough blood to function normally due to an obstruction of the blood vessels and the cells die (infarction or thrombotic stroke), or when a blood vessel ruptures (hemorrhagic stroke). Common symptoms of stroke include sudden paralysis or loss of sensation in part of the body (especially on one side), partial loss of vision or double vision, loss of balance, slurred speech, or confusion. Stroke can also result in a decline in cognitive mental functions such as memory, speech and language, thinking, organization, reasoning, or judgment. If these symptoms are severe enough to interfere with everyday activities, they are called dementia.Symptoms of stroke-related dementia may occur abruptly over weeks or months or develop gradually over years. Symptoms of stroke-related dementia include inattention, poor concentration, difficulty following instructions, difficulty planning and organizing tasks, confusion, wandering, getting lost in familiar surroundings, poor judgment, difficulties with reasoning or problem solving, psychosis (agitation, aggression, hallucinations, delusions, loss of contact with reality, inability to relate appropriately to surroundings and other people), mood and behavior changes, depression, or laughing or crying inappropriately.
Stroke-Related Dementia Symptoms
Cognitive symptoms may appear abruptly, over weeks or months in a stepwise manner, or even gradually over years. The appearance of symptoms varies by the type of stroke and the part of the brain affected. Cognitive decline usually occurs within 3 months of a recognized stroke and may indicate vascular dementia.
The following are common symptoms of vascular dementia:
- Memory loss, especially problems remembering recent events
- Inattention, poor concentration, difficulty following instructions
- Difficulty planning and organizing tasks
- Wandering, getting lost in familiar surroundings
- Poor judgment
- Difficulties with calculations, reasoning, or problem solving
- Psychosis - Agitation, aggression, hallucinations, delusions, loss of contact with reality, inability to relate appropriately to surroundings and other people
- Mood and behavior changes
- Laughing or crying inappropriately
Stroke-Related Dementia Causes
Vascular dementia is not a single disease but a group of conditions relating to different vascular problems. What all the conditions have in common is that a critical part of the brain does not receive enough oxygen. The vascular damage underlying stroke-related dementia occurs in several different patterns.
- Multi-infarct dementia - Occurs after a series of strokes in different parts of the brain
- Single-infarct dementia - Occurs when one large vascular lesion causes a severe infarction, or there is a single infarction in a strategic area of the brain
- Dementia due to lacunar lesions - Occurs when only the smaller arteries are affected, causing multiple small infarctions
- Binswanger disease - Also a disease of small arteries, but the damage primarily occurs in the white matter area of the brain
- Dementia due to hemorrhagic (bleeding) stroke - Occurs when a blood vessel bursts causing bleeding in the brain
The major cause of the vascular lesions underlying stroke-related dementia is untreated high blood pressure (hypertension). Diabetes, atherosclerosis (“hardening of the arteries”), heart disease, high cholesterol, peripheral vascular disease, and smoking are other risk factors. Other causes include uncommon vascular diseases.
Vascular dementia may occur with Alzheimer's Disease. ApoE4 is a protein whose main role is to help transport cholesterol in the blood. A high level of this protein in the blood poses a significant risk factor for Alzheimer dementia and has been linked to vascular dementia.
When the brain’s blood supply is inadequate, a stroke results. Stroke symptoms (for example, loss of arm or leg function or slurred speech) signify a medical emergency because without treatment, blood-deprived brain cells quickly become damaged or die, resulting in brain injury, serious disability, or death. Call 9-1-1 if you notice stroke symptoms developing in someone.
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.