Dose of rTPA in ischaemic stroke is
The core concept here is knowing the correct dosage for acute ischemic stroke treatment. The key points would be the weight-based dosing and the maximum dose. I remember that rTPA is typically given as a bolus followed by an infusion. The standard dose is up to 0.9 mg/kg, with a maximum of 90 mg. So for a patient weighing more than 100 kg, the maximum would apply. The bolus is 10% of the total dose given over 1 minute, and the remaining 90% infused over an hour.
Now, the correct answer should be 0.9 mg/kg up to 90 mg. Let me think about the options. The options aren't provided, but common distractors might include incorrect weight-based doses, wrong maximum limits, or other agents like alteplase. Wait, alteplase is another name for rTPA, so maybe that's a distractor in another question. But here, the question is about the dose.
For the wrong options, maybe someone might confuse it with a lower dose like 0.6 mg/kg or a higher max dose. Also, there's a difference between IV and intra-arterial administration, but the standard for IV is 0.9 mg/kg. Another possible error is mixing up the bolus and infusion parts but the total dose is what's important here.
Clinical pearl: The maximum dose is crucial because exceeding it can lead to increased risk of hemorrhage. Also, the time window for administration is within 4.5 hours from symptom onset, which is another key point but not part of the question here.
So putting it all together, the correct answer is 0.9 mg/kg up to 90 mg. The explanation should highlight the weight-based calculation and the maximum limit. The incorrect options would be wrong for different reasons like lower doses, higher maximums, or different agents.
**Core Concept**
The question tests knowledge of the dosing regimen for recombinant tissue plasminogen activator (rTPA), a thrombolytic agent used in acute ischemic stroke. The correct dose is weight-based but capped at a maximum total dose to balance efficacy and hemorrhagic risk.
**Why the Correct Answer is Right**
The standard rTPA dose for acute ischemic stroke is **0.9 mg/kg up to a maximum of 90 mg**. This is administered as an initial bolus (10% of the calculated dose over 1 minute) followed by a 60-minute infusion of the remaining 90%. The weight-based calculation ensures adequate fibrinolytic activity while minimizing intracranial hemorrhage risk. The 90 mg cap prevents overdose in heavier patients. This regimen is supported by guidelines like the American Heart Association (AHA) and European Stroke Organization (ESO).
**Why Each Wrong Option is Incorrect**
**Option A:** A lower dose (e.g., 0.6 mg/kg) would be insufficient to lyse clots effectively.
**Option B:** A higher maximum dose