A transient ischemic attack (TIA) is a transient episode of acute-onset neurologic symptoms that localize to a specific vascular territory or fit a described stroke syndrome. TIAs tend to be brief, lasting on the order of minutes to hours. Patients with transient symptoms lasting hours that would have formerly been diagnosed with TIA are now being found with evidence of cerebral ischemia on MRI. When a patient develops sudden-onset focal neurologic symptoms that could be due to a TIA or stroke, emergent medical attention is required, as there is no way to predict whether symptoms will resolve, and life-saving acute therapies may be given under certain conditions (thrombolytics or thrombectomy).

The pathophysiology of TIAs is thought to be due to reversible episodes of focal brain ischemia caused by the same mechanisms as in acute ischemic stroke:

• Cardioembolic disease (commonly atrial fibrillation)
• Large vessel disease (commonly atherosclerotic disease of the carotid arteries or vertebrobasilar arteries)
• Small vessel disease (lacunar stroke syndromes commonly due to long-standing hypertension and diabetes)

Risk factors for TIAs include aging and vascular risk factors (ie, hypertension, dyslipidemia, diabetes, long-standing smokers). Patients who are in a hypercoagulable state (due to malignancy, genetic disorders, or other hematologic disorders) are also at increased risk.

Common symptoms include hemi-weakness of the face, hand, arm, or leg, hemi-sensation loss, aphasia, dysarthria, dysphagia, dizziness, diplopia, monocular vision loss, and difficulty walking. Findings fit within a specific vascular territory or stroke syndrome. Rarely, a patient might have limb shaking as a manifestation of transient ischemia (but other more common causes need to be considered).

Certain populations, such as children, are less likely to be affected; however, TIA / stroke should be considered in young patients with moyamoya disease, congenital heart disease, bacterial endocarditis, sickle cell anemia, mitochondrial disease, or homocystinuria. Patients taking oral contraceptives or estrogen may be at a higher risk at a younger age.

Related topics: cerebellar stroke, cerebral stroke, drug-induced stroke