Atherosclerosis is one of the conditions that can cause cerebrovascular disease. During this process, high cholesterol levels coupled with inflammation in areas of the arteries in the brain can cause the cholesterol to build up in the vessel in the form of a thick, waxy plaque. This plaque can limit, or completely obstruct, blood flow to the brain, causing a stroke, transient ischemic attacks, or dementia, which may lead to a variety of other health complications.
The most common forms of cerebrovascular disease are cerebral thrombosis (40% of cases) and cerebral embolism (30%), followed by cerebral hemorrhage (20%).
Another form of cerebrovascular disease includes aneurysms. In females with defective collagen, the weak branching points of arteries give rise to protrusions with a very thin covering of endothelium that can tear to bleed easily with minimal rise of blood pressure. This can also occur with defective capillaries caused by tissue cholesterol deposition especially in hypertensive subjects with or without dyslipidemia. If bleeding occurs in this process, the resulting effect is a hemorrhagic stroke in the form of subarachnoid hemorrhage, intracerebral hemorrhage or both.
A fall in blood pressure during sleep can then lead to a marked reduction in blood flow in the narrowed blood vessels causing ischemic stroke in the morning. Conversely, a sudden rise in blood pressure due to excitation during the daytime can cause tearing of the blood vessels resulting in intracranial hemorrhage. Cerebrovascular disease primarily affects people who are elderly or have a history of diabetes, smoking, or ischemic heart disease.
What are the symptoms of Cerebrovascular Disease?A symptom is something the patient senses and describes, while a sign is something other people, such as the doctor notice. For example, drowsiness may be a symptom while dilated pupils may be a sign.
The signs and symptoms of cerebrovascular disease depend on the location of the hemorrhage, thrombus, or embolus and the extent of cerebral tissue affected. General signs and symptoms of a hemorrhagic or ischemic event include motor dysfunction, such as hemiplegia and hemiparesis.
Early in a cerebrovascular attack (CVA), the patient may experience flaccid paralysis, followed by increased muscle tone and spasticity. He may lose his gag reflex and ability to cough. He may have communication deficits, such as dysphagia, receptive or expressive aphasia, dysarthria, and apraxia. He also may develop spatial and perceptual deficits, such as the loss of half of his visual field (homonymous hemianopia) and the inability to recognize an object (agnosia).
Other signs and symptoms of a CVA include vomiting, seizures, fever, ECG abnormalities, confusion that leads to a complete loss of consciousness, labored or irregular respirations, apneic periods, increased blood pressure, and bowel and bladder incontinence.
Signs and symptoms specific to a hemorrhagic CVA include abrupt onset of a severe headache, nuchal rigidity, and rapid onset of complete hemiplegia. As the hematoma enlarges, the patient's neurologic deficits worsen from gradual loss of consciousness to coma.
Symptoms of a thrombotic CVA follow the "stroke in evolution" pattern and include the progressive deterioration of motor and sensory function, slow deterioration of speech, and lethargy. These signs and symptoms peak when edema develops, usually about 72 hours after the onset of the thrombotic event.
For a patient with an embolic CVA, signs and symptoms include a sudden onset of motor and sensory deficits, deteriorated speech, and headache on the side of the head where the embolism is occurring. If the embolus breaks into smaller pieces and the occlusion resolves, these signs and symptoms may dissipate.
What are the causes of Cerebrovascular Disease?Ischemic stroke occurs when a blood vessel that supplies blood to the brain is blocked by a blood clot. A clot may form in an artery that is already very narrow. This is called a thrombus. If it completely blocks the artery, it is called a thrombotic stroke. Also a clot may break off from somewhere in the body and travel up to the brain to block a smaller artery. This is called an embolism. It causes an embolic stroke.
Ischemic strokes may also be caused by blood clots that form in the heart. These clots travel through the blood and can get stuck in the small arteries of the brain. This is known as a cerebral embolism.
Certain drugs and medical conditions can make your blood more likely to clot and raise your risk for ischemic stroke. A common cause of ischemic stroke in people under age 40 is carotid dissection, or a tear in the lining of the carotid artery. The tear lets blood flow between the layers of the carotid artery. This causes narrowing of the carotid artery that is not due to plaque buildup.
Hemorrhagic stroke occurs when a blood vessel in part of the brain becomes weak and bursts open, causing blood to leak into the brain. Some people have defects in the blood vessels of the brain that make this more likely. The flow of blood that occurs after the blood vessel ruptures damages brain cells.
Major modifiable risk factors include hypertension, smoking, obesity, and diabetes.
Diagnosing Cerebrovascular DiseaseIn the physical examination, a doctor listens with the help of a stethoscope to detect abnormal sounds of blood flow (called bruit) on the neck. However, in severe cases of atherosclerosis, the bruit is less common.
A physician may look for specific neurological, motor and sensory deficits such as changes in vision or visual fields, abnormal reflexes, abnormal eye movements, muscle weakness, decreased sensation and other changes.
A Cerebral Angiography, Vertebral Angiogram or Carotid Angiogram is also a possibility. In this radiological diagnostic method in which a catheter (a long narrow flexible tube) is inserted into the patient's artery with the help of a needle and guided through the main vessels of the abdomen and chest until it is placed in the arteries of the neck. The whole procedure is monitored with the help of a fluoroscope. X-ray pictures are taken after injecting a contrast dye in the neck with the help of the catheter.
A CAT scan is used to diagnose and detect hemorrhagic strokes, since blood, bone and brain tissue can be easily distinguished due to their difference in densities. It is important to note that damage from ischemic stroke cannot be detected by this scanning method.
What are the treatment options for Cerebrovascular Disease?Blood platelet inhibitors such as Aspirin, Dipyridamole, Ticlopidine, Clopidogrel and Sulfinpyrazone are effective in reducing the risk for stroke. These drugs have been effective in treating patients with a history of stroke or patients at risk for a stroke event.
Carotid Endarterectomy is a procedure in which an incision is made into the carotid artery and the plaque removed with the help of a dissecting tool thus enabling normal blood flow. Then the artery is repaired with sutures or a graft.
In Carotid Angioplasty and stenting a balloon tipped catheter is inserted into the artery and the balloon inflated to press against the plaque so as to flatten the plaque and reopen the artery. A tiny, slender metal mesh tube (stent) is fitted inside the carotid artery to improve the blood flow in the arteries blocked by plaque. The stent helps in preventing the artery from collapsing or closing up after the procedure is complete.
Preventing Cerebrovascular DiseaseCerebrovascular disease can be best prevented by abiding by the following recommendations: quitting smoking, regular physical exercise, eating heart healthy diet with low fat content, maintaining healthy weight or avoiding obesity, controlling blood pressure, controlling hypertension, avoiding anger or chronic stress and lowering blood cholesterol.
Written by Sy Kraft (B.A.)