Acute stroke diagnosis

Abstract

Stroke can be categorized as ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. Awakening with or experiencing the abrupt onset of focal neurologic deficits is the hallmark of ischemic stroke diagnosis. The most common presenting symptoms for ischemic stroke are difficulty with speech and weakness on one half of the body. Many stroke mimics exist; two of the most common are a postictal seizure and hypoglycemia. Taking a detailed history and performing ancillary testing will usually exclude stroke mimics. Neuroimaging is required to differentiate ischemic stroke from intracerebral hemorrhage, as well as to diagnose entities other than stroke. The choice of neuroimaging depends on its availability, eligibility for acute stroke interventions, and the presence of patient contraindications. Subarachnoid hemorrhage presents most commonly with severe headache and may require analysis of cerebrospinal fluid when neuroimaging is not definitive. Public education of common presenting stroke symptoms is needed for patients to activate emergency medical services as soon as possible after the onset of stroke.

Figure 1

Algorithm for the diagnosis of acute stroke.

Figure 2

Head computed tomography (CT) scans showing (A) an intracerebral hemorrhage and (B) subarachnoid hemorrhage. Note that acute hemorrhage appears hyperdense (white) on a CT scan.

Figure 3

(A) Noncontrast computed tomography (CT) showing two hypodense regions indicating old infarctions in the distribution of the left-middle cerebral (arrow) and posterior cerebral arteries (arrow). (B) Diffusion-weighted magnetic resonance imaging obtained shortly after the CT reveals a new extensive infarction (arrow) in the right-middle cerebral artery distribution not evident on the CT. Reprinted with permission from Image source Wilford Hall Medical Center, as archived in MedPix.

Figure 4

Time course of diffusion-weighted imaging abnormalities. Diffusion-weighted imaging can detect ischemic stroke in the very early period (six-hour image). Lesions typically reach maximum intensity three to five days after stroke onset (as shown in the 58-hour image), then typically fade over one to four weeks (abnormality still seen in seven-day image, but has disappeared in the 134-day image).