Vascular dementia is an umbrella term that describes impairments in cognitive function caused by problems in the blood vessels that feed the brain.
In some cases, a blood vessel may be completely blocked, causing a stroke. Some strokes result in dementia while others don't. It depends on the severity of the stroke and the portion of the brain that's affected. Vascular dementia also can occur when blood vessels in the brain narrow, reducing the amount of blood flow to those sections of the brain.
The prevalence of vascular dementia ranges from 1 percent to 4 percent in people over the age of 65. The risk increases dramatically with age.
Vascular dementia is most often caused by either a narrowing or a complete blockage of one or more blood vessels in the brain.
The complete blockage of an artery in the brain usually causes a stroke (infarction), but some blockages don't produce stroke symptoms. These "silent brain infarctions" increase a person's risk of vascular dementia. The risk increases with the number of infarctions experienced over time. One variety of vascular dementia is called multi-infarct dementia.
Although not all strokes result in vascular dementia, as many as a third of the people who have a stroke will experience dementia within six months.
Vascular dementia also can occur without a complete blockage of an artery. Portions of the brain can be starved for oxygen and food by reduced blood flow from arteries narrowed by vascular disease.
Vascular dementia can also be caused by:
One of the most perplexing things about vascular dementia is that it usually occurs simultaneously with Alzheimer's disease. In other words, most people with vascular dementia also have some Alzheimer's disease.
- Profoundly low blood pressure
- Brain damage caused by brain hemorrhage
- Blood vessel damage from such disorders as lupus erythematosus or temporal arteritis
Increasing age is one of the biggest risk factors for vascular dementia. The disorder rarely occurs before the age of 65. And people in their 80s and 90s are much more likely to have vascular dementia than people in their 60s and 70s. Other risk factors include :
- History of stroke. The brain damage that occurs with strokes — especially those that affect language — appears to increase the risk of developing dementia.
- High blood pressure. Hypertension puts extra pressure on blood vessels throughout the body. This increases the risk of vascular problems in the brain.
- Diabetes. High glucose levels damage blood vessels throughout the body, increasing the risk of stroke and other vascular problems in the brain.
Vascular dementia symptoms can vary, depending on the portion of the brain that's affected. People with vascular dementia can exhibit:
One of vascular dementia's earliest symptoms typically involves a decline in the ability to organize thoughts or actions. This makes it difficult to keep track of more than one thing at a time or to communicate details in a sequential manner.
- Confusion and agitation
- Problems with language and memory
- Unsteady gait, causing falls
- Urinary frequency, urgency or incontinence
- Personality and mood changes
Vascular dementia symptoms often begin suddenly and may worsen in a step-wise fashion, following a series of strokes or mini-strokes. But some forms of vascular dementia develop gradually and can easily be confused with Alzheimer's disease. One difference is that memory loss is one of the first symptoms of Alzheimer's. In vascular dementia, memory problems typically occur much later in the disease process.
Alzheimer's disease and vascular dementia often occur together. In fact, some scientists believe that it's more common for these two disorders to occur together than apart.
If vascular dementia is suspected, doctors often order either computerized tomography (CT) or magnetic resonance imaging (MRI) scans of the brain to check for infarcts in the brain. A special type of MRI scan, called an MR angiogram can be done to check for narrowed or blocked arteries. A Doppler ultrasound of the arteries in the neck that feed the brain also may be warranted. Neuropsychological tests can help detect the degree and types of cognitive impairment.
Computerized tomography (CT)
A CT scan uses special X-ray equipment to produce a cross-sectional image showing a slice of your body's organs and tissues. For CTs of the head, you should remove earrings, eyeglasses, dentures, dental implants and hairpins.
A contrast material may be injected to help highlight any abnormalities in your brain's blood vessels. This contrast material contains iodine, so make sure your doctor knows if you're allergic to it. Your doctor may choose a different test if you have diabetes, asthma, multiple myeloma or any disorder of the heart, kidneys or thyroid gland.
A CT scan is painless. You lie down on a pallet that slides into the machine. A special head holder may be used to keep your skull in the proper position.
Magnetic resonance imaging (MRI)
An MRI scan uses radio waves and a strong magnetic field to produce detailed images of internal organs and tissues. Metal on or in your body may be pulled toward the magnet and may distort the final images. In some cases, contrast material may be injected to produce even more detailed pictures.
MRIs are painless, although you must hold very still for up to 15 minutes at a time. For a brain MRI, you lie down on a padded table that slides into the machine. Before you enter the machine, a radio antenna device is positioned around the upper part of your head.
Some people experience a feeling similar to claustrophobia when they're inside an MRI machine. If you think this will be a problem, your doctor can prescribe medication to help you relax. The machine makes a loud knocking noise during operation. Earplugs can help.
Doppler ultrasound uses high-frequency sound waves to measure the direction and speed of blood cells as they travel through blood vessels — such as the carotid arteries, which travel through either side of your neck to connect your heart and brain.
A Doppler ultrasound of your carotid arteries can help your doctor determine if there are blockages or narrow places impeding blood flow to your brain.
Some neuropsychological tests take only a few minutes, while others can take more than an hour. These exams test orientation, recall, attention, calculation and language. Exam results for people with vascular dementia typically show the same types of cognitive deficits as the exam results of people who have Alzheimer's disease. One major difference, however, is in memory function. Most people with vascular dementia don't experience memory problems until late in the course of the disease.
There is no cure for vascular dementia and no drugs have been approved by the Food and Drug Administration to treat it. However, medications designed to treat the symptoms of Alzheimer's disease also appear to help people with vascular dementia.
Cholinesterase inhibitors — such as donepezil (Aricept), galantamine (Razadyne) and rivastigmine (Exelon) — are Alzheimer's drugs that work by boosting levels of a chemical messenger involved in memory and judgment. Side effects can include nausea, vomiting and diarrhea.
Another Alzheimer's drug, called memantine (Namenda), also has been shown to provide a modest benefit in people who have vascular dementia. Memantine works by regulating a chemical messenger involved in information processing, storage and retrieval. Side effects can include headache, constipation, confusion and dizziness.
Doctors sometimes prescribe both types of drugs, memantine and one of the cholinesterase inhibitors.
Keeping your blood pressure in the normal range can help prevent dementia in general. One study showed that the risk of Alzheimer's disease and vascular dementia was halved in people who controlled their high blood pressure with a calcium channel blocker. The use of a diuretic plus an ACE inhibitor appears to slightly reduce the risk of dementia.
Cholesterol-lowering medications also seem to help, probably by reducing the amounts of deposits building up inside the brain's arteries.
Avoiding the onset of diabetes, with diet and exercise, is another way to decrease your risk of dementia. If you already have diabetes, controlling your glucose levels can reduce vascular damage and improve cognitive function.
|Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.