Stroke risk factors, migraines, and dementia
Types, causes, and risks of cerebrovascular accidents
Thrombotic stroke: A blood clot (thrombus) forms in a cerebral artery and blocks distal blood flow.
Embolic stroke: A blood clot from elsewhere in the body (e.g., the lower leg) or a piece of plaque (typically from the carotid arteries) breaks away and flows through the bloodstream to the brain; the embolus eventually blocks a cerebral artery, causing distal ischemia.
Cerebral hemorrhage: An artery in the brain ruptures, possibly because of untreated or uncontrolled hypertension or a congenital aneurysm.
Transient ischemic attack (TIA): A temporary disruption of blood flow to the brain that produces stroke-like symptoms - such as weakness, numbness, or speech difficulty - that resolve completely, usually within minutes to a few hours, without lasting brain damage. A TIA is a warning sign that a full stroke may occur soon and requires prompt medical evaluation.
Any of the following factors can increase the risk of a stroke:
- Hypertension
- Diabetes (increases the risk by two to three times)
- Hypercholesterolemia
- Cigarette smoking (increases the risk by 50%)
- Obesity
- Family history of stroke; risk of a first stroke is nearly twice as high for African-Americans
- Endocarditis (may promote thrombus formation)
- Arteriosclerosis and atherosclerosis
- Heart disease (e.g., atrial fibrillation, which increases the risk by five times)
- Sleep apnea
- Sickle cell anemia
- Cocaine abuse
Individuals with three or more of the following five health conditions are twice as likely to have a cerebrovascular accident:
- Obesity
- Low level of high-density lipoprotein (HDL) cholesterol
- High triglyceride level
- Blood pressure ≥130/85 mm Hg
- Diabetes and/or prediabetes (fasting blood sugar of 100 to 125 mg/dL)
Notice the overlap with the risk factors above - obesity, hypertension, and diabetes appear on both lists, compounding stroke risk when combined.
Migraine headache
About 12% of the U.S. population suffers from migraine headaches; three times more women than men are affected. Migraine headaches are paroxysmal attacks of headaches that can be completely incapacitating and frequently are associated with other symptoms, such as nausea, vomiting, visual disturbances, and throbbing pain on one side of the head. The manifestations of migraine headaches differ from one individual to another. The patient may experience a sensory warning sign, or aura, before the onset of the headache. An aura often consists of some form of visual disturbance, such as dark lines or spots within the visual field or a flash of light.
Medical science has not yet discovered the underlying cause of migraines. However, researchers believe they may be caused by a combination of a problem with the trigeminal nerve and an imbalance of chemicals in the brain, especially the neurotransmitter serotonin. Individuals who suffer from migraine headaches report a number of different triggers, including changes in estrogen levels; certain foods, such as alcohol, chocolate, aspartame, caffeine, and monosodium glutamate (MSG); elevated stress levels; bright lights, sun glare, and certain smells; altered sleep patterns; skipped meals and dehydration; intense physical exertion; and changes in the weather, especially with changing altitude levels and barometric pressures. The diagnosis is usually established from a complete medical history. An EEG, a CT scan, or an MRI study may be performed as part of the diagnostic process to rule out other causes of the headaches.
Drugs used to treat migraines include nonsteroidal anti-inflammatory drugs (NSAIDs) and triptans, such as sumatriptan (Imitrex), rizatriptan (Maxalt), and zolmitriptan (Zomig), which mimic the effects of serotonin, causing vascular constriction. These drugs must be taken at the onset of the headache to be effective and can be delivered via different routes: oral medications, nasal sprays, or intravenously (IV). Other medications recommended for the prevention of migraines include beta blockers and antidepressants. Antiseizure medications, such as topiramate (Topamax) and gabapentin (Neurontin), may be effective in reducing the frequency and severity of the headaches. Other treatments include biofeedback techniques and elimination diets to avoid migraine triggers.
Dementia and Alzheimer’s disease
The term dementia describes a group of symptoms caused by altered brain function. Dementia symptoms may include short-term memory loss; disorientation about person, time, and place; neglect of personal hygiene, nutrition, and safety; personality changes; and inability to follow simple directions. Dementia can be caused by multiple conditions. Some are reversible, such as nutritional disorders or disorientation caused by a minor head injury, while others are irreversible, such as multi-infarct (vascular) dementia and Alzheimer’s disease.
Multi-infarct dementia is caused by a series of small strokes that interfere with the brain’s blood supply, resulting in multiple areas of tissue necrosis. The location of the infarcts determines the degree of disability and the dementia symptoms that might occur. Symptoms of an acute onset of dementia are typically caused by this type of dementia. People with multi-infarct dementia are likely to show signs of improvement or remain stable for long periods and then quickly develop new symptoms if more strokes occur. Untreated or uncontrolled hypertension usually is the cause of this type of dementia.
Alzheimer’s disease is the most common form of dementia among older people today. It is a devastating, chronic, progressive, and degenerative disease that begins in the parts of the brain that control thought, memory, and language. The patient exhibits slow, increasing loss of recent memory; loss of recognition of people, places, and events; confusion and disorientation; and physical deterioration that leads to death. The cause remains unknown, and there is no known cure. Treatment is supportive care only.