Neurology · Cerebrovascular Accident
The facts most likely to be tested
The non-contrast head CT is the initial diagnostic test of choice to rapidly exclude intracranial hemorrhage before initiating any reperfusion therapy.
Intravenous alteplase (tPA) or tenecteplase is indicated for patients with ischemic stroke within 4.5 hours of symptom onset, provided there are no absolute contraindications.
Mechanical thrombectomy is the standard of care for patients with a large vessel occlusion (LVO) in the anterior circulation within 24 hours of symptom onset.
Blood pressure must be lowered to <185/110 mmHg prior to the administration of thrombolytics to reduce the risk of symptomatic intracranial hemorrhage.
Aspirin should be administered within 24 to 48 hours after the onset of an ischemic stroke, but it must be withheld for at least 24 hours if the patient received thrombolytic therapy.
Hyperacute stroke management requires immediate blood glucose testing to rule out hypoglycemia, which can mimic focal neurologic deficits.
Permissive hypertension (up to 220/120 mmHg) is allowed in patients with acute ischemic stroke who are not candidates for thrombolytics or thrombectomy to maintain cerebral perfusion pressure.
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A 68-year-old male is brought to the emergency department by his wife due to the sudden onset of right-sided hemiparesis and expressive aphasia. Symptoms began 2 hours ago while he was eating breakfast. His medical history is significant for atrial fibrillation and hypertension. On examination, his blood pressure is 175/95 mmHg, and his NIH Stroke Scale (NIHSS) score is 16. A non-contrast head CT shows no evidence of hemorrhage or established infarct.
What is the most appropriate next step in management?
Intravenous thrombolysis (alteplase or tenecteplase)
The patient is within the 4.5-hour window for thrombolysis, and the non-contrast CT has successfully ruled out intracranial hemorrhage, making him a candidate for reperfusion therapy.
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Etiology / Epidemiology
Primary risk factors include hypertension, atrial fibrillation, and diabetes. Ischemic strokes account for 85% of cases.
Clinical Manifestations
Sudden focal neurological deficits; FAST (Face, Arm, Speech, Time) criteria. Contralateral hemiparesis is the hallmark.
Diagnosis
Non-contrast CT head is the gold standard to rule out hemorrhage. MRI diffusion-weighted imaging is the most sensitive.
Treatment
Alteplase (tPA) within 4.5 hours; mechanical thrombectomy for large vessel occlusion. Do not lower BP <185/110 if tPA candidate.
Prognosis
Time is brain; 3-month modified Rankin Scale is the standard outcome measure. Hemorrhagic transformation is a major risk.
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Epidemiology & Etiology
Stroke is the leading cause of long-term disability. Hypertension remains the single most significant modifiable risk factor. Embolic sources, primarily from atrial fibrillation, cause the majority of cardioembolic strokes.
Pertinent Anatomy
The Circle of Willis provides collateral circulation. Occlusion of the Middle Cerebral Artery (MCA) is the most common site, resulting in dense contralateral motor and sensory deficits.
Pathophysiology
Ischemia triggers the ischemic cascade, leading to ATP depletion and failure of ion pumps. This causes cytotoxic edema and eventual infarction core surrounded by the penumbra. The penumbra is the salvageable tissue targeted by reperfusion therapy.
Clinical Manifestations
Patients present with sudden onset focal deficits. Aphasia suggests dominant hemisphere involvement, while hemineglect suggests non-dominant parietal lobe injury. Sudden thunderclap headache suggests subarachnoid hemorrhage rather than ischemic stroke.
Diagnosis
The Non-contrast CT head must be performed immediately to exclude hemorrhage. MRI diffusion-weighted imaging is the most sensitive test for early ischemia. CT angiography is required to identify candidates for mechanical thrombectomy.
Treatment
Administer Alteplase within 4.5 hours of symptom onset if no contraindications exist. Absolute contraindications include active internal bleeding, history of intracranial hemorrhage, or recent surgery. Perform mechanical thrombectomy for large vessel occlusions up to 24 hours post-onset.
Prognosis
Early intervention significantly improves the modified Rankin Scale score. Monitor for hemorrhagic transformation and cerebral edema, which may require decompressive hemicraniectomy.
Differential Diagnosis
Hypoglycemia: mimics focal deficits; check fingerstick glucose immediately
Todd's paralysis: transient focal deficit following a seizure
Complex migraine: aura mimics stroke but follows a slower progression
Bell's palsy: involves the entire side of the face, sparing the forehead
Brain tumor: presents with progressive rather than sudden onset symptoms