CEREBROVASCULAR DISEASE DEFINITION
To function properly, the brain needs oxygen and nutrients that are provided by the blood. However, if the blood supply is restricted or stopped, brain cells die, leading to brain damage and possibly death.
A stroke happens when the blood supply to part of the brain is blocked or interrupted – for example, by a blood clot (where the blood thickens and solidifies). This is the most common cause of stroke and is known as an ischaemic stroke.
CEREBROVASCULAR DISEASE CAUSES
There are a number of causes of cerebrovascular disease, including atherosclerosis, a condition in which high cholesterol and arterial inflammation in the brain cause the cholesterol to build up into a thick, waxy plaque that can obstruct the flow of blood to the brain, causing ischemic stroke or transient ischemic attack, or dementia. Blood clots may also form in an already-narrow artery, creating a thrombus; when the entire artery becomes blocked, this is called a thrombotic stroke. In addition, a clot may break off from somewhere else in the body and travel up to the brain and block a smaller artery there; this is called an embolism, and it causes an embolic stroke.
Certain drugs and medical condition (e.g., carotid dissection, or a tear in the lining of the carotid artery) can increase a person’s risk of ischemic stroke, especially in people under the age of 40 who do not necessarily have plaque buildup.
While it can sometimes be difficulty to detect cerebrovascular disease before an attack happens, risk factors include hypertension, smoking, obesity, ischemic heart disease and uncontrolled diabetes.
CEREBROVASCULAR DISEASE PATHOPHYSIOLOGY
A stroke (apoplexy) is the sudden onset of weakness, numbness, paralysis, slurred speech, aphasia, problems with vision and other manifestations of a sudden interruption of blood flow to a particular area of the brain. The ischemic area involved determines the type of focal deficit that is seen in the patient.
Transient Ischemic Attack (TIA)
A TIA is similar to a stroke, but the interruption of blood flow is temporary. The clot resolves sporadically. The symptoms are relatively the same as a stroke but last less than 24 hours, whereas stroke symptoms persist for greater than 24 hours.
Causes of Stroke
The primary pathophysiology of stoke is an underlying heart or blood vessel disease. The secondary manifestations in the brain are the result of one or more of these underlying diseases or risk factors. The primary pathologies include hypertension, atherosclerosis leading to coronary artery disease, dyslipidemia, heart disease, and hyperlipidemia. The two types of stroke that result from these disease states are ischemic and hemorrhagic strokes.
Non-reducable Risk Factors
- The possibilities of a stroke occurring increases with age. For every decade (10 years) over the age of 55, the possibility of a stroke occurring doubles. A patient that is 75 years of age has four times the risk of having a stroke compared to someone who is 55 years old. Of all strokes that occur in people, approximately 65% occur in those who are over the age of 65.
- Those who have had a stroke or TIA are more likely to have another stroke or transient ischemic attack. Approximately 60% of strokes occur in patients who have had a previous TIA.
- Strokes generally occur more often in males than females, until the age of 55; after age 55 the risk is the same for both men and women.
- The occurrence of stroke is higher in the African-American, Hispanic, and Asian-Pacific Islander population than in other ethnical backgrounds.
- Patients who have immediate family members (mother, father, or sibling) that have had a stroke or TIA are at greater risk for having a stroke or TIA than those who do not have a family history with these events.
- People who have diabetes are also at greater risk of stroke that those without diabetes.
Reducable Risk Factors
- Lower your high blood pressure. Hypertension (high blood pressure) is the number one most treatable risk factor for stroke. You can help prevent a TIA or stroke considerably by working to lower your blood pressure.
- Lowering cholesterol levels may decrease the risk of stroke. By working to lower your cholesterol, you can help prevent a TIA or stroke.
- Stop smoking. If you stop smoking, you can decrease your risk for stroke to that of a non-smoker within two to five years.
- Management of heart disease and diabetes may also help to decrease your risk of stroke.
CEREBROVASCULAR DISEASE SYMPTOMS
The symptoms of cerebrovascular disease will depend on the location of the patient’s hemorrhage, thrombus or embolism, as well as the extent to which the cerebral tissue has been affected. In general, the signs of a hemorrhagic or ischemic attack include motor dysfunction.
In the early stages of a cerebrovascular attack, the patient often experiences flaccid paralysis (i.e., paralysis characterized by limp, unresponsive muscles), followed by spasticity and increased muscle tone. The patient may also lose his or her gag reflex and ability to cough, and may have communication problems such as dysphagia, receptive or expressive aphasia, dysarthria and apraxia. Also, he or she may develop spatial and/or perceptual benefits, including conditions called homonymous hemianopia (loss of half of the visual field) and agnosia (an inability to recognize an object).
Other symptoms of cerebrovascular disease are vomiting, seizures, fever, electrocardiogram irregularities, confusion leading to a loss of consciousness, breathing difficulty, increased blood pressure, and bowel and bladder incontinence. Signs of a hemorrhagic cerebrovascular attack into an abrupt, severe headache, nuchal rigidity and complete hemiplegia (i.e., paralysis affecting one side of the body). As the hematoma grows larger, patients’ neurological problems worsen from a gradual loss of consciousness to coma.
Symptoms of a thrombotic cerebrovascular attack include a progressive deterioration of motor and sensory function, slow deterioration of speech and lethargy, while symptoms of an embolic cerebrovascular attack include a sudden onset of motor and sensory problems, deteriorated speech and headache on one side of the head.
CEREBROVASCULAR DISEASE DIAGNOSIS
A doctor commonly diagnoses a stroke through a physical examination of the person affected as well as a description of the symptoms they are experiencing. A doctor attempts to find the location in the person’s brain that has experienced damage through testing involving a CT or MRI scans, which may also help to rule out brain hemorrhage or tumors. A doctor considers the person’s age, as well as any vascular, cardiac, or brain conditions the person may have. The doctor will attempt to determine whether the stroke was either hemorrhagic or ischemic. Ischemic strokes are often followed by additional strokes unless the problem is treated. A doctor may order an EEG if the person has experienced seizure activity, or an echocardiogram if they have a pre-existing heart condition. A doctor will attempt to rule out things such as encephalitis, meningitis, bleeding inside the person’s skull, neurodegenerative disorders, brain abscess, or migraines as causes of the stroke symptoms the person is experiencing.
There are a number of tests that a doctor can use to assist in reaching a diagnosis of cerebrovascular disease. The majority of the tests involved are designed to detect carotid artery disease (CAD) before the person experiences a stroke. CAD, unlike hemorrhagic cerebrovascular disease, often progresses for many years while presenting no symptoms at all, accounting for approximately ninety-five percent of all cases of cerebrovascular disease.
CEREBROVASCULAR DISEASE TREATMENT
Experts at Atlantic Neuroscience Institute’s Stroke Centers at Overlook Medical Center and Morristown Medical Center are available around the clock to treat patients with cerebrovascular disease, a group of disorders affecting the blood vessels in the brain.
About 80 percent of stroke patients have blocked arteries in the brain that starve part of the brain of its blood supply. In the other 20 percent of stroke patients, blood vessels burst as the result of an abnormal out pouching of an artery, an aneurysm, or a ruptured small artery.
Physicians at both of our Stroke Centers assess patients rapidly to determine the cause of the stroke. If an artery is blocked, several treatment options are available, but speed is essential because the brain rapidly dies when deprived of blood. Intravenous tPA (the “clot busting” drug) can be used effectively in these patients if it is administered in the first three hours following the stroke.
For patients with bleeding from an aneurysm, new endovascular procedures, which work inside the blood vessels, enable surgeons to operate on the brain without opening the skull (craniotomy). In some patients bleeding arises from an abnormal tangle of arteries and veins, called an arteriovenous malformation. This condition can also be treated with an endovascular approach, sparing patients the risk, discomfort and longer hospitalization of a craniotomy.