Acute ischemic stroke
USMLE Step 2 CKDifficulty: mediumLast updated:
A 66-year-old right-handed man is brought to the emergency department 80 minutes after his wife saw him suddenly develop right arm and face weakness and difficulty speaking during breakfast. He has hypertension and takes amlodipine; he takes no anticoagulants. He has had no recent surgery, trauma, or bleeding. Blood pressure is 172/94 mm Hg and fingerstick glucose is 118 mg/dL. Examination shows expressive aphasia and right face and arm weakness. Noncontrast head CT shows no hemorrhage or established infarct. Platelet count and INR are normal.
Which of the following is the most appropriate next step in management?
Answer and explanation
Correct answer: A. Intravenous thrombolysis with alteplase (or tenecteplase)
This patient has an acute ischemic stroke with a clearly known onset 80 minutes ago, a disabling deficit (aphasia and hemiparesis), no hemorrhage on CT, and no listed contraindications. The source states that recombinant tPA (alteplase) can be used up to 3 hours after symptom onset in patients without contraindications, and up to 4.5 hours with additional exclusion criteria. Tenecteplase 0.25 mg/kg is an equally acceptable agent within 4.5 hours (European Stroke Organisation 2023). His blood pressure is below the pre-thrombolysis targets the source gives, so it does not delay treatment. Imaging beyond noncontrast CT should not delay thrombolysis, although vessel imaging is recommended when large-vessel occlusion is suspected. The source also notes that anticoagulants and antiplatelet drugs are not used within 24 hours after tPA.
Each option explained
- A. Intravenous thrombolysis with alteplase (or tenecteplase)Correct. Within the treatment window, with no hemorrhage and no contraindications, IV thrombolysis is indicated.
- B. Aspirin 325 mg orally now, without thrombolysisIncorrect. Aspirin alone forgoes reperfusion in an eligible patient; antiplatelets are withheld for 24 hours after thrombolysis.
- C. Intravenous unfractionated heparin infusionIncorrect. Heparin is not used for acute reperfusion and is withheld for 24 hours after thrombolysis.
- D. Obtain an MRI of the brain before any treatment decisionIncorrect. MRI is not required before thrombolysis and would delay time-sensitive treatment.
- E. Lower blood pressure to below 140/90 mm Hg over the next 24 hours before considering further therapyIncorrect. His blood pressure is acceptable for thrombolysis; delaying 24 hours would miss the treatment window.
Key point
An eligible patient with acute ischemic stroke and no hemorrhage on CT should receive IV thrombolysis within 4.5 hours of onset (ideally within 3 hours).
From the source
“Recombinant tPA ( alteplase) can be used for patients with acute ischemic stroke up to 3 hours after symptom onset if they have no contraindications to tPA”