-IBIS-1.5.0-
tx
nervous system
cerebrovascular accident/TIA
diagnoses
definition and etiology
definition:
CVA (cerebrovascular disease, stroke) is defined as an ischemic vascular injury to the brain. TIA (transient ischemic attack): a type of minor stroke: refers to focal neurologic abnormalities of sudden onset and brief duration (typically minutes) that arise from injury in the internal carotid-middle cerebral or vertebral-basilar arterial system.
etiology:
TIA: often, the attacks are recurrent and are premonitions for a full stroke in the future. Most TIAs are from arteriosclerotic emboli. Risk factors include high blood pressure, heart disease, atherosclerosis, diabetes mellitus, and polycythemia.
CVA: In a classic stroke, the neurologic defects continue to expand for 24-48 hours after the infarction occurs ("stroke in evolution"). The most frequently seen stroke is called a "completed stroke", whose symptoms develop rapidly and maximally within a few minutes to an hour. The term "completed stroke" also refers to the fully established neurologic deficits after the stroke, whether from the acute or gradual kind. Neurologic symptoms solely relate to the area of cerebral infarction.
signs and symptoms
signs and symptoms:
TIA: sudden onset:
Symptoms last from 2-10 minutes generally.
Symptom expression is related to which arterial system sustained the injury:
» Carotid artery: Unilateral presentation, with ipsilateral blindness; contralateral paralysis with paresthesias; slurred speech; aphasia may occur.
» Vertebrobasilar arteries: Confusion; vertigo; diplopia or blindness; bilateral weakness and paresthesias of the limbs: may cause the person to fall to the ground ("drop attacks"); slurred speech.
CVA:
Symptoms also depend on the arteries injured:
» Middle cerebral artery: Contralateral hemiplegia; aphasia.
» Internal carotid artery: Same as middle cerebral artery.
» Anterior cerebral artery: Uncommon: contralateral hemiplegia, poor grasp reflex and urinary incontinence; apathy; confusion.
» Posterior cerebral artery: Contralateral homonymous hemianopia; hemisensory loss; spontaneous thalamus pain.
» Vertebrobasilar system: Ophthalmoplegia; pupillary abnormalities; changes in consciousness; dysarthria; dysphagia. This type of stroke is often fatal.
lab findings:
TIA:
(+) Doppler sonography.
(+) Angiography.
CVA: lab not usually necessary: clinical diagnosis is typically adequate.
Rule out polycythemia, anemia, infections.
Chest x-ray: rule out lung tumor and CV problems.
CSF: usually normal, may be bloody.
Angiography to identify the site of the injury.
CT scan to differentiate ischemic stroke from intercerebral hemorrhage, hematoma, or tumor.
course and prognosis
TIA: Treatment should be directed to correcting any present risk factors, such as lowering cholesterol or hypertension. Anticoagulants, platelet inhibitors, or resection of the artery are other conventional treatments.
CVA: The course or prognosis is unknown during the early days, unless death occurs. About 35% of patients die in hospital, and the mortality rate increases with age. The eventual amount of neurologic damage depends on the patient's age, state of health, and size and location of the stroke. It is unusual for total recovery to occur but the sooner improvement is seen, the better the prognosis for minimal deficits. Any deficit present after 6 months is likely to be permanent, but neurological retraining programs appear to be having some success. Further CVAs are common.
differential diagnosis
Migraine.
Convulsive seizures.
Neoplasms.
Meniere's disease.
Hyperinsulinism in diabetes mellitus patients.
Head injury.
Meningitis.
Uremia.
Hepatic coma.
Alcohol or drug intoxication.
Poisoning.
Epilepsy.
Differentiate hemorrhagic from ischemic causes.
footnotes