Review Question - QID 205003

The patient in this vignette is most likely suffering from an acute left MCA stroke. Initial work-up of a patient with concern for stroke is a non-contrast head CT in order rule out a hemorrhagic stroke before administering tPA.

The reason to get a non-con head CT in suspected stroke is not to distinguish between ischemic and hemorrhagic stroke, but rather to rule out hemorrhage. An acute ischemic stroke is diagnosed by diffusion weighted MRI or by using the clinical history (i.e. don't delay tPA just to get an MRI if there is strong clinical suspicion and no evidence of bleed). In fact, in many cases, you may see nothing on a noncon head CT. If an ischemic stroke suspected clinically and CT is negative for evidence of a hemorrhagic stroke, the recommended treatment is to give IV tPA if the presentation is within 3-4.5 hours. For embolic disease and hypercoagulable states give warfarin or aspirin only once the hemorrhagic stroke has been ruled out. Of note, a contraindication to tPA is systolic BP > 185 or diastolic BP > 110 mm Hg.

Yew and Cheng discuss strokes which can be classified into ischemic stroke, intracerebral hemorrhage, and subarachnoid hemorrhage. The classic presentation of an ischemic stroke is awakening with or the abrupt onset of focal neurologic deficits, the most common being difficulty with speech and weakness on one half of the body. A postictal seizure and hypoglycemia may mimic an ischemic stroke.

Nentwich and Veloz discuss neuroimaging in the setting of an acute stroke, in which non contrast brain CT should be the first study. Because CT functions to rule out a hemorrhagic stroke, further studies should be undertaken if the CT is negative of which MR, specifically diffusion-weighted imaging and others, are the most widely used. MR studies may show which brain regions are already infarcted and which are at risk of infarction if perfusion is not restored.

Illustration A shows an MR of an acute left MCA stroke. The left is pane is a T2WI image while right is FLAIR.

Incorrect Answers:
Answer 1: tPA should only be administered after a hemorrhagic stroke has been ruled out.
Answer 2: Chewing an aspirin is used in the treatment of acute myocardial infarction, not acute stroke.
Answer 4: Contrast head CT is not used in the diagnosis of acute stroke.
Answer 5: A diffusion weighted image should be acquired after a non-contrast head CT.