Cerebral Palsy

Cerebrovascular Accidents ("Strokes")
Strokes or aopolexy is a condition resultant of a more or less abrupt interruption of the blood supply to some area of the brain. When a person suffers a stroke, he develops the following conditions:
1) The closure of a blood vessel in the brain due to a clot (thrombosis)
2) A blood clot from elsewhere in the body is carried to a blood vessel in the brain, thus blocking the vessel.
3) One of the blood vessels in the brain ruptures, causing haemorrhage.

Cerebral thrombosis
This is a form of stroke in which the artery, which is the seat of arteriosclerosis, becomes progressively narrower through thickening of its wall. Eventually, complete closure of the vessel takes place and blood flow is interrupted. The areas of brain normally supplies by that blood vessel will degenerate and die. Usually, paralysis of one or more limbs is found on the opposite side of the brain (hemiplegia). Loss of speech will also occur if the thrombosis is on the dominant hemisphere, which is usually the left side of the brain in a right-handed person and the right side of the brain in a left-handed person.
Symptoms of cerebral thrombosis may be caused by the narrowing and hardening of the carotid arteries in the neck. The carotid arteries, which carry blood to the front half of the brain, are most frequently involved. For symptoms to develop, the carotid artery would have to be approximately 80% percent narrowed.

"Small Stroke"
This refers to an interruption in the flow of blood to an area of the brain resulting from a condition that lasts from a few minutes to twenty-four hours and is followed by recovery. Such an episode is too short to cause much permanent brain damage and is referred to as a transient ischemic attack. If, however, the condition lasts longer than twenty-four hours, a small amount of brain tissue may die. This dead area of the brain is called an infarct. It is impossible to predict the outcome following a "small" stroke. It is impossible to determine initially if the episode will be transient or will become permanent. It has been estimated that nearly 75% of patients with a complete stroke have a history of transient ischemic attacks. In other words, a warning of a potential catastrophe occurs in most cases.

Ischemia
This is the decreased or interrupted flow of blood through an artery. Several ischemic attacks can occur without producing any permanent brain damage.

Cerebral embolism
This is a condition in which an artery of the brain becomes blocked by a blood clot originating from some distant site. If the embolus is small, a transient ischemic attack with full recovery usually takes place. If the clot includes a larger blood vessel, there may be loss of consciousness and complete paralysis, usually on one side of the body. If the dominant side of the brain is involved, there will be loss of speech (aphasia).

Cerebral haemorrhage
This occurs when a blood vessel within the brain ruptures, Stroke is most common in people with high blood pressure or in a disease where bleeding takes place. If a large blood vessel is involved, the patient may die rather quickly. If the blood vessel is small, a small area of the brain may be damaged, and the patient often makes a good recovery. Sometimes, bleeding into the subarachnoid space surrounding the brain may occur. The subarachnoid space is a narrow space between the brain and its outside covering, the dura mater. It contains cerebrospinal fluid and blood vessels carrying blood to and from the brain. The cause of bleeding into the subarachnoid spcae results most frequently from the rupture of an aneurysm. Less often, it is also caused by a malformation of an artery or vein of the brain. An aneurysm is a saclike dilation of a blood vessel. Aneurysms are generally located along the major blood vessels at the base of the brain. Symptoms are produced by sudden rupture of the sac, resulting in bleeding. Severe headache, drowsiness, and loss of consciousness usually ensue. Sometimes, the headache will be of short duration without loss of consciousness. Pressure on the optic nerve may be result in blindness; pressure on other parts of the brain may lead to epileptic seizures. An arteriovenous malformation is a cluster of abnormally large blood vessels that may be located on the surface of the brain or within the brain substance. Symptoms may be produced by rupture of a blood vessel, resulting in headache and drowsiness simliar to an aneurysm.

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