neurologic disorders
Ischemic Stroke
Symptoms and Signs of Ischemic Stroke
Symptoms and signs of ischemic stroke depend on the part of brain affected. Patterns of neurologic deficits often suggest the affected artery (see table), but correlation is often inexact. Deficits may become maximal within several minutes of onset, typically in embolic stroke. Less often, deficits evolve slowly, usually over 24 to 48 hours (called evolving stroke or stroke in evolution), typically in atherothrombotic stroke. In most evolving strokes, unilateral neurologic dysfunction (often beginning in one arm, then spreading ipsilaterally) extends without causing headache, pain, or fever. Progression is usually stepwise, interrupted by periods of stability. A stroke is considered submaximal when after it is complete, there is residual function in the affected area, suggesting viable tissue at risk of damage. Embolic strokes often occur during the day; headache may precede neurologic deficits. Thrombi tend to occur during the night and thus are first noticed on awakening. Lacunar infarcts may produce one of the classic lacunar syndromes (eg, pure motor hemiparesis, pure sensory hemianesthesia, combined hemiparesis and hemianesthesia, ataxic hemiparesis, dysarthria–clumsy hand syndrome); signs of cortical dysfunction (eg, aphasia) are absent. Multiple lacunar infarcts may result in Vascular Cognitive Impairment and Dementia . A seizure may occur at stroke onset, more often with embolic than thrombotic stroke. Seizures may also occur months to years later; late seizures result from scarring or hemosiderin deposition at the site of ischemia. Occasionally, fever develops. Deterioration during the first 48 to 72 hours after onset of symptoms, particularly progressively impaired consciousness, results more often from cerebral edema than from extension of the infarct. Unless the infarct is large or extensive, function commonly improves within the first few days; further improvement occurs gradually for up to 1 year. 