Stroke: Listen to the Warnings

Definition
Transient ischemic attack, TIA, or "mini" stroke is a temporary reduction of blood flow to part of the brain. Tissue death does not result and most symptoms resolve in an hour, with full resolution within 24 hours. TIA is a warning sign of an impending CVA (Medical, 2007).

Cerebrovascular accident, CVA, ischaemic stroke, or stroke occurs when the blood supply to the brain is compromised. Some areas of the brain suffer anoxia, a lack of oxygen to the cells, causing cell death and long term impairment or death of the body (Stroke, 2007).

Etiology
CVA
There are three main causes of stroke. The first is cerebral thrombosis, in which a clot forms within the brain and blocks a cerebral artery from perfusing the organ. Next is the cerebral embolism. This type of stroke occurs when a thrombus is formed in another part of the body and travels to the brain through the vasculature in an embolic stroke. Once there, the clot becomes lodged in an artery within the brain, causing blockage (Stroke, 2007). The final cause of stroke is cerebral hemorrhage. This happens when a blood vessel within the brain bursts, leaking blood freely into the brain, inducing further brain damage (Cerebral, 2007). Strokes can involve small or large sections of the brain (Stroke, 2007).

TIA
Transient ischemic strokes are caused by temporary blockages of cerebral arteries. This may be due to a clot that later shifts or dissolves. Another possible cause is hyper- or hypotension. Either condition can decrease blood flow to organs, as can diabetes. TIA's do not cause permanent damage, so residual effects are undetectable on MRI's and CT scans (NINDS, 2007).

Signs and Symptoms
CVA
Strokes are like snowflakes and fingerprints. No two are exactly the same. The location of the injury within the brain, combined with the severity of the event, determine the symptoms exhibited by the patient. The most common signs of stroke include numbness, weakness, or paralysis of the face, arm and leg of one side of the body (hemiparesis). Speech can become garbled, slurred, or nonexistent. Language may be unintelligible to the patient. Swallowing may be difficult or impossible and the subject may drool. Balance, vision, and breathing may be affected (Stroke, 2007). Consciousness may be altered. In severe CVA's the patient may lose consciousness. The prognosis for such patients is poor. Other symptoms include vertigo, severe headache (hemorrhagic CVA), flushed complex-ion, noisy breathing, and possibly hypoxia induced seizures (Cerebral, 2007). No patient experiences the whole range of symptoms.

TIA
The signs and symptoms are the same as with CVA, but they resolve within 24 hours (Transient, 2007).

Risk Factors
Risk factors for CVA and TIA include heredity, hypo- or hypertension, smoking, athero-sclerosis, irregular heartbeat (clots form in the heart and travel to the brain), diabetes, excessive alcohol intake, and head injury (particularly to the back of the skull) (Stroke, 2007).

Treatment
The first line of defense in the case of either CVA or TIA is low dose aspirin (75 mg) (Medical, 2007). From there anticoagulants are used in ischaemic stroke with surgery for extreme cases and in the event of hemorrhagic stroke (Cerebral, 2007). If hypertension is present it is now the practice not to treat it for several days after the stroke. A sudden decrease in blood pressure can increase hypoxia and result in more brain damage (Stroke, 2007).

Prognosis
The patient who experiences TIA's recovers fully. This is often a precursor to a more severe event and should therefore be evaluated and treated for any risk factors present (NINDS, 2007). Ischaemic strokes differ in severity and can range from almost complete recovery to immobilization, coma, or death. Hemorrhagic strokes are almost always fatal (Stroke, 2007).

Works Cited

Cerebral Hemorrhage. Retrieved on 6/2/07.

http://www.ambulancetechnicianstudy.co.uk/cva.html

Medical Encyclopedia: TIA. Retrieved on 6/2/07.

http://www.nlm.nih.gov/medlineplus/print/ency/article/000730.htm

NINDS: TIA Information Page. Retrieved on 6/2/07.

http://www.ninds.nih.gov/disorders/tia/tia.htm?css=print

Stroke (Cerebrovascular Accident). Retrieved on 6/2/07.

http://www.netdoctor.co.uk/diseases/facts/stroke.htm

Transient Ischemic Attack. Retrieved on 6/2/07.

http://www.nlm.nih.gov/medlineplus/print/transientischemicattack.html