Definition   

A stroke is when the blood supply to any part of the brain is interrupted, resulting in tissue death and loss of brain function.

Causes and risks   

The most common cause of stroke is atherosclerosis. (See stroke secondary to atherosclerosis.) A stroke may be caused by a blood clot that forms in the brain (a thrombus) or a blood clot, piece of plaque, or other material that travels to the brain from another location (an embolism). Bleeding (hemorrhage) within the brain can, on rare occasions, cause symptoms that mimic stroke.
A stroke caused by a blood clot in the brain (a thrombus) is most common in older people, and often there is underlying atherosclerosis or diabetes. This type of stroke may occur at any time, including at rest. The person may or may not lose consciousness.
Strokes caused by embolism (a blood clot that travels to the brain) are most commonly caused by heart disorders .The probable outcome is worsened if blood vessels damaged by stroke rupture and bleed (hemorrhagic stroke).

Prevention   

Stroke prevention involves controlling the risk factors. Treat hypertension, diabetes, heart disease, and other associated disorders. Reduce or stop smoking. A low-cholesterol, low-salt diet may be appropriate if the risk factors include atherosclerosis or hypertension. Exercise more.

Symptoms   

• Loss of movement (paralysis) of any body area
• Weakness
• Decreased sensation
• Numbness
• Tingling or other sensation changes
• Decreased vision
• Loss of memory
• Vertigo (abnormal sensation of movement)
• Loss of coordination
• Swallowing difficulties
• Consciousness changes:
• Urinary incontinence (lack of control over bladder) 

Tests may determine the location and cause of the stroke and rule out other disorders that can cause the symptoms:

• A head CT or MRI of head may be used to rule out bleeding (hemorrhage) or other lesions and define the location and extent of the stroke
• An ECG (electrocardiogram) may be used to determine underlying heart disorders
• An echocardiogram may be used if the cause is suspected to be cardiac embolus
• A carotid duplex (ultrasound) may be used if the cause is suspected to be carotid artery stenosis
• A cerebral (head) arteriography may be used if a disorder involving the blood vessels is suspected

Treatment   

IMMEDIATE TREATMENT
Life support and coma treatment are performed as needed.

A number of medications may be used. RTPA is a medicine that lyses the clot and potentially restores blood flow to the affected area to prevent cell death and permanent damage. However, there are strict criteria for who can receive RTPA -- most important is that the stroke victim be evaluated and treated by a specialized stroke team within 3 hours of onset of symptoms. It is a controversial medication because there is a risk of serious bleeding.

In appropriate circumstances, other anti-coagulants such as heparin and coumadin are used to prevent recurrent strokes. Aspirin and other anti-platelet agents are used to prevent strokes as well.

Analgesics may be needed to control severe headache. Anti-hypertensive medication may be needed to control high blood pressure.

Nutrients and fluids may be necessary, especially if the person has swallowing difficulties. The nutrients and fluids may given through an intravenous tube or a tube in the stomach (feeding tube or gastrostomy tube). Swallowing difficulties may be temporary or permanent.

Surgery may be appropriate in some cases, including surgical removal of blood clots from the brain.

Carotid endarterectomy, removal of plaque from the carotid arteries, may help prevent new strokes from occurring in some people.

LONG-TERM TREATMENT
The recovery time and need for long-term treatment vary. Depression and other symptoms should be treated.

Speech therapy, occupational therapy, physical therapy, positioning, range of motion exercises, and other therapies may prevent complications and promote maximum recovery of function. People should stay active within their physical limitations. In some cases, urinary catheterization or bladder/bowel control programs may be necessary to control incontinence.

 Complications   

• Pressure sores
• Permanent loss of movement or sensation of a part of the body
• Bone fractures
• Joint contractures
• Muscle spasticity
• Permanent loss of cognitive or other brain functions
• Disruption of communication, decreased social interaction
• Decreased ability to function or care for self
• Decreased life span
• Multi-infarct dementia
• Side effects of medications
• Aspiration
• Malnutrition
• Pain syndromes (reflex sympathetic dystrophy)