Intravenous PA is indicated in ischemic stroke within how many hours of onset of disease process
**Core Concept**
Intravenous thrombolysis with recombinant tissue plasminogen activator (tPA) is a time-sensitive treatment for acute ischemic stroke, aiming to dissolve occluding clots and restore blood flow to the affected brain area. The efficacy of tPA is significantly reduced if administered beyond a certain time window following stroke onset.
**Why the Correct Answer is Right**
The American Heart Association and American Stroke Association recommend administering intravenous tPA within 4.5 hours of ischemic stroke onset. The treatment window is restricted due to the risk of hemorrhagic transformation, which increases with time. The optimal time for tPA administration is within 3 hours of stroke onset, but it can be extended to 4.5 hours in selected cases.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the recommended time window for intravenous tPA administration is not 2 hours.
**Option B:** This option is incorrect because the recommended time window for intravenous tPA administration is not 6 hours.
**Option C:** This option is incorrect because the recommended time window for intravenous tPA administration is not 8 hours.
**Clinical Pearl / High-Yield Fact**
It is essential to note that the time window for tPA administration can be longer in patients with wake-up strokes, where the exact time of stroke onset is unknown. However, even in these cases, the treatment should not be delayed beyond 4.5 hours.
**Correct Answer:** C. 4.5 hours