Stroke secondary to carotid stenosis

Carotid stenosis, X-ray of the left artery

Carotid stenosis, X-ray of the right artery

Stroke secondary to carotid stenosis

Definition:

A group of brain disorders involving loss of brain function caused by obstruction of the carotid arteries. This is usually related to hardening of the arteries (atherosclerosis).

Causes, incidence, and risk factors:

Stroke secondary to carotid stenosis occurs when a major portion of one or both carotid arteries (the arteries in the neck that supply blood to the brain) is narrowed or blocked.

Atherosclerosis (hardening of the arteries) is a condition where fatty deposits occur in the inner lining of the arteries, and atherosclerotic plaque (a mass consisting of fatty deposits and blood platelets) develops. The plaque may obstruct the artery or a clot (thrombus) may occur at the site of the plaque and also cause obstruction. Blockage of the artery usually develops slowly. Sometimes, however, a piece of atherosclerotic plaque (an embolism) may break off and travel to an artery in the brain causing obstruction far from the initial site where the plaque developed.

Atherosclerotic plaque does not always lead to stroke. There are many small blood vessels around the carotid arteries. If blood flow gradually decreases, these small connections will increase in size and "by-pass" the obstructed area (collateral circulation). If there is enough collateral circulation, even a totally blocked artery may not cause neurologic deficits. A second safety mechanism is that the arteries are large enough that 70 % of the blood vessel can be occluded, and there will still be adequate blood flow to the brain.

Stroke secondary to carotid stenosis is most common in older people, and often, there is underlying atherosclerotic heart disease and/or diabetes mellitus.

Risks are the same as for stroke secondary to atherosclerosis.

Symptoms:

weakness or total inability to move a body part
numbness, loss of sensation
tingling or other abnormal sensations
decreased or lost vision (may be partial or temporary)
language difficulties (aphasia)
inability to recognize or identify sensory stimuli (agnosia)
loss of memory
loss of coordination
swallowing difficulties
personality changes
mood and emotion changes
urinary incontinence (lack of control over bladder)
lack of control over the bowels
consciousness changes:
- sleepy
- stuporous, somnolent, lethargic
- comatose, unconscious

Signs and tests:

An examination may include neurologic, motor, and sensory examination to determine the specific neurologic deficits present, because they often correspond closely to the location of the injury to the brain. The examination may show emboli in the retina, changes in reflexes including abnormal reflexes or abnormal extent of "normal" reflexes, muscle weakness, decreased sensation, and other changes. A bruit (an abnormal sound heard with the stethoscope) may be heard over the carotid arteries of the neck.

Additional tests include:

high serum lipids, especially triglycerides and cholesterol
carotid artery stenosis or complete occlusion showing on
- carotid or cerebral angiography
- carotid Duplex/Doppler ultrasound
- MRI of the head
- MRA of the brain vessels and neck vessels (carotid and vertebral arteries)

Treatment:

See Stroke.

For additional treatment, anti-hypertensive medication may be needed to control high blood pressure. Medications to control blood cholesterol levels may be required.

Carotid endarterectomy, surgical removal of plaque from the carotid arteries, may be indicated to prevent new strokes from occurring, especially if there is more than 70% of the carotid artery occluded and there are no contraindications (reasons against the surgery) such as coexisting terminal illness or dementia.

Expectations (prognosis):

Stroke is the third leading cause of death in developed countries. About one-fourth of the sufferers die as a result of the stroke or its complications, about one-half have long-term disabilities, and about one-fourth recover most or all function.

Complications:

See Stroke.

Calling your health care provider:

Go to the emergency room or call the local emergency number (such as 911) if symptoms occur.

Prevention:

Prevention includes control of risk factors. Hypertension, diabetes, heart disease, and other risk factors should be treated as appropriate. Smoking should be minimized or, preferably, stopped.

Treatment of TIA (transient ischemic attack, "warning strokes") may prevent some strokes.

Review Date: 5/10/2002
Reviewed By: Elaine T. Kiriakopoulos, M.D., MSc, Department of Neurology, Beth Israel Deaconess Medical Center, Harvard University, Boston, MA. Review provided by VeriMed Healthcare Network.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed physician should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. Copyright 2003 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.