Transient Ischemic Attack Information - symptom, cause, treatment of
transient ischemic attack tia
Transient Ischemic Attack Information
Transient ischemic attacks are characterized by focal ischemic cerebral neurologic deficits that last for less than 24 hours (usually less than 1-2 hours). About 30% of patients with stroke have a history of transient ischemic attacks, and proper treatment of the attacks is an important means of prevention. The incidence of stroke does not relate to either the number or the duration of individual attacks but is increased in patients with hypertension or diabetes. The risk of stroke is highest in the month after a transient ischemic attack and progressively declines thereafter.
Symptoms and Signs of Transient Ischemic Attack
The symptoms of transient ischemic attacks vary markedly among patients; however, the symptoms in a given individual tend to be constant in type. Onset is abrupt and without warning, and recovery usually occurs rapidly, often within a few minutes.
If the ischemia is in the carotid territory, common symptoms are weakness and heaviness of the contralateral arm, leg, or face, singly or in any combination. Numbness or paresthesias may also occur either as the sole manifestation of the attack or in combination with the motor deficit. There may be slowness of movement, dysphasia, or monocular visual loss in the eye contralateral to affected limbs. During an attack, examination may reveal flaccid weakness with pyramidal distribution, sensory changes, hyperreflexia or an extensor plantar response on the affected side, dysphasia, or any combination of these findings. Subsequently, examination reveals no neurologic abnormality, but the presence of a carotid bruit or cardiac abnormality may provide a clue to the cause of symptoms.
Vertebrobasilar ischemic attacks may be characterized by vertigo, ataxia, diplopia, dysarthria, dimness or blurring of vision, perioral numbness and paresthesias, and weakness or sensory complaints on one, both, or alternating sides of the body. These symptoms may occur singly or in any combination. Drop attacks due to bilateral leg weakness, without headache or loss of consciousness, may occur, sometimes in relation to head movements.
Treatment of Transient Ischemic Attack
When arteriography reveals a surgically accessible high-grade stenosis (70–99% in luminal diameter) on the side appropriate to carotid ischemic attacks and there is relatively little atherosclerosis elsewhere in the cerebrovascular system, operative treatment (carotid thromboendarterectomy) reduces the risk of ipsilateral carotid stroke, especially when transient ischemic attacks are of recent onset (< 2 months). Surgery is not indicated for mild stenosis (< 30%); its benefits are unclear with severe stenosis plus diffuse intracranial atherosclerotic disease.
In patients with carotid ischemic attacks who are poor operative candidates (and thus have not undergone arteriography) or who are found to have extensive vascular disease, medical treatment should be instituted. Similarly, patients with vertebrobasilar ischemic attacks are treated medically and are not subjected to arteriography unless there is clinical evidence of stenosis or occlusion in the carotid or subclavian arteries.
Medical treatment is aimed at preventing further attacks and stroke. Cigarette smoking should be stopped, and cardiac sources of embolization, hypertension, diabetes, hyperlipidemia, arteritis, or hematologic disorders should be treated appropriately.