Pathophysiology of Cerebrovascular Accident (CVA)
Cerebrovascular accident or stroke (also called brain attack) results from sudden interruption of blood supply to the brain, which precipitates neurologic dysfunction lasting longer than 24 hours. Stroke are either ischemic, caused by partial or complete occlusions of a cerebral blood vessel by cerebral thrombosis or embolism or hemorrhage (leakage of blood from a vessel causes compression of brain tissue and spasm of adjacent vessels). Hemorrhage may occur outside the dura (extradural), beneath the dura mater (subdural), in the subarachnoid space (subarachnoid), or within the brain substance itself (intracerebral).
Risk factors for stroke include transient ischemic attacks (TIAs) – warning sign of impending stroke – hypertension, arteriosclerosis, heart disease, elevated cholesterol, diabetes mellitus, obesity, carotid stenosis, polycythemia, hormonal use, I.V., drug use, arrhythmias, and cigarette smoking. Complications of stroke include aspiration pneumonia, dysphagia, constractures, deep vein thrombosis, pulmonary embolism, depression and brain stem herniation.