A patient presents with facial droop and unilateral weakness within 3 hours of onset. What is the ischemic stroke treatment window for tPA?

• A. Eligible for tissue plasminogen activator within 3 hours of onset; earlier treatment is better
• B. Eligible for tissue plasminogen activator within 4.5 hours of onset; earlier treatment is better
• C. Eligible within 6 hours
• D. There is no time limit for tPA

Answer: (B)

The key idea here is the time window for giving IV tPA in an acute ischemic stroke and why getting treatment promptly matters. IV alteplase can be administered within 4.5 hours from when symptoms first started, for patients who meet criteria. The sooner you treat, the more brain tissue you can save, because clot dissolution reduces ongoing brain injury and improves functional outcomes. In this scenario, the patient is within 3 hours of onset, so they are certainly within the window, and the window itself extends to 4.5 hours. That’s why the best statement is that the patient is eligible within 4.5 hours, and earlier treatment is better.

The other options don’t fit because there is a defined maximum window (4.5 hours) for IV tPA in ischemic stroke, not 6 hours or no time limit. Saying eligibility ends at 4 hours is overly restrictive, and stating there is no time limit is incorrect.