Stroke secondary to carotid stenosis

Definition
Stroke secondary to carotid stenosis is a group of brain disorders involving loss of brain function due to the obstruction of blood flow to the brain. 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.

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

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.

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

Risks are the same as for stroke secondary to Atherosclerosis. Radiation therapy to the area may also cause carotid stenosis.

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:       o Sleepiness       o Stupor, Lethargy       o Coma, unconsciousness

Signs and tests
Neurologic, motor, and sensory examinations may be done to determine specific neurologic deficits, because they often correspond closely to the location of the injury to the brain. The examination may show emboli in the retina, abnormal reflexes or abnormal extent of “normal” reflexes, muscle weakness, decreased sensation, or 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       o Carotid or Cerebral Angiography       o Carotid duplex or Doppler ultrasound       o MRI of the head       o MRA (magnetic resonance angiography) of the brain vessels and neck vessels

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.

Johns Hopkins patient information

Last revised: December 5, 2012
by Potos A. Aagen, M.D.

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