Stroke, also called brain attack, occurs when blood flow to the brain is disrupted. Disruption in blood flow is caused when either a blood clot blocks one of the vital blood vessels in the brain (ischemic stroke), or when a blood vessel in the brain bursts, spilling blood into surrounding tissues (hemorrhagic stroke).

The more common form of stroke, ischemic stroke can occur when debris within the body's arteries travels "upstream" and blocks off an artery supplying blood to the brain. In many cases, a narrowed carotid artery in the neck is the source of this debris. Therefore, people with narrowing in the carotid artery, a condition called carotid artery disease, are at a higher risk of stroke.

The brain needs a constant supply of oxygen and nutrients in order to function. Even a brief interruption in blood supply can cause problems. Brain cells begin to die after just a few minutes without blood or oxygen.

The presence of stroke symptoms for a period of less than 24 hours is called a Transient Ischemic Attack (TIA), or a "mini-stroke." Most often, a TIA is a warning-sign for a stroke. Even though the symptoms may disappear, it is crucial to seek medical treatment immediately upon experiencing a TIA.

Symptoms

Stroke is an emergency and should be treated as such. The greatest chance for recovery from stroke occurs when emergency treatment is started immediately. The most common symptoms of a stroke are:

• Sudden weakness or numbness of the face, arm, or leg, especially on one side of the body
• Sudden confusion or difficulty speaking or understanding
• Sudden problems with vision such as dimness or loss of vision in one or both eyes
• Sudden dizziness or problems with balance or coordination
• Sudden problems with movement or walking
• Sudden, severe headaches with no other known cause

Other, less common, symptoms of stroke may include the following:

• Sudden nausea, vomiting, or fever not caused by a viral illness
• Brief loss or change of consciousness such as fainting, confusion, seizures, or coma
• TIA (the transient presence of any of the above symptoms for less than 24 hours)

Diagnosis

If you have had a stroke or a TIA and your doctor suspects that you may have a significant degree of stenosis in your carotid arteries, she or he will conduct an examination consisting of specific tests to determine the extent of the carotid artery disease including:

• Duplex ultrasound
• Cerebral angiogram
• Magnetic Resonance Angiogram (MRA)
• CT scan

Treatment

Recognition and management of the risk factors for stroke can help to prevent stroke. Important risk factors for stroke include high blood pressure, elevated cholesterol, heart disease or angina, blocked arteries to the legs, prior stroke, and TIA's. In addition, carotid artery disease is an important risk factor for stroke. Several treatments may be provided to help prevent an ischemic stroke from occurring in people with carotid artery disease.

Mild carotid artery disease can sometimes be treated with medication and risk factor modification such as smoking cessation and reduction of cholesterol levels, and monitored for progression to a more severe form.

More severe disease is generally treated with an operation called carotid endarterectomy. In certain individuals a minimally invasive procedure called carotid stenting may be possible.