Mixed-Case Remediation and Exam-Day Readiness
Key Takeaways
- IV alteplase is 0.9 mg/kg (max 90 mg): 10% as a 1-minute bolus, remainder over 60 minutes; tenecteplase 0.25 mg/kg (max 25 mg) is a single bolus alternative; window ≤3 h, extended to 4.5 h in eligible patients.
- BP must be <185/110 before thrombolysis and kept <180/105 for 24 hours after; without tPA, ischemic stroke uses permissive hypertension (treat only if >220/120).
- Thrombectomy treats large vessel occlusion within 6 hours, extended to 24 hours in selected patients meeting DAWN/DEFUSE-3 perfusion-mismatch criteria.
- Hemorrhagic targets differ: acute ICH SBP goal ~130–140; SAH uses nimodipine to prevent vasospasm; glucose target 140–180 mg/dL and normothermia for all stroke types.
- Outcome scales: NIHSS (0–42, severity) at the bedside; modified Rankin Scale (mRS 0–6) for functional disability at follow-up.
Final Cram Sheet: Thrombolysis and Thrombectomy
This section is a high-yield consolidation — commit these numbers to memory. IV thrombolysis is the most tested topic on the SCRN.
| Parameter | Alteplase (tPA) | Tenecteplase (TNK) |
|---|---|---|
| Dose | 0.9 mg/kg, max 90 mg | 0.25 mg/kg, max 25 mg |
| Administration | 10% as bolus over 1 min, rest over 60 min | Single IV bolus |
| Window | ≤3 h (up to 4.5 h if eligible) | similar; favored when thrombectomy planned |
| BP before | <185/110 | <185/110 |
| BP after (24 h) | <180/105 | <180/105 |
Mechanical thrombectomy treats large vessel occlusion (LVO):
- Standard window: within 6 hours of last-known-well.
- Extended window: up to 24 hours in selected patients meeting DAWN/DEFUSE-3 criteria (clinical–core or perfusion–core mismatch on advanced imaging).
- Thrombectomy and IV thrombolysis are complementary, not exclusive — give tPA if eligible and proceed to thrombectomy for LVO; never delay one waiting on the other.
Rapid-fire eligibility reminders that trip up candidates: the window is measured from last-known-well, not from when symptoms were noticed; a CT showing hemorrhage absolutely excludes thrombolysis; and BP that cannot be safely brought below 185/110 is a contraindication to tPA. For the extended thrombectomy window, the gate is advanced perfusion imaging (CT perfusion or MR DWI/PWI) demonstrating salvageable tissue — a patient beyond 6 hours without qualifying mismatch imaging is generally not a candidate.
Tenecteplase is increasingly the agent of choice when an LVO will go to thrombectomy because its single bolus is faster to administer than the alteplase infusion.
Final Cram Sheet: BP, Glucose, and Temperature Targets
Blood-pressure management is mechanism-specific — the most common reason candidates miss points is applying the wrong target to the wrong stroke type.
| Situation | Blood-pressure target |
|---|---|
| Ischemic, NOT receiving tPA | Permissive hypertension; treat only if >220/120 |
| Ischemic, tPA candidate (before) | <185/110 |
| Ischemic, after tPA (24 h) | <180/105 |
| Acute intracerebral hemorrhage (ICH) | Lower acutely to SBP ~130–140 (avoid <130) |
| Subarachnoid hemorrhage (SAH), pre-securing | Modest control (often SBP <140–160); avoid extremes |
Universal physiologic targets for all stroke types:
- Glucose: maintain 140–180 mg/dL. Treat hyperglycemia (worsens outcomes) and promptly correct hypoglycemia (a stroke mimic).
- Temperature: normothermia. Treat fever (>38°C / 100.4°F) with antipyretics; fever worsens ischemic injury.
- Dysphagia screen before ANY oral intake (including oral meds and water) to prevent aspiration pneumonia.
- SAH-specific: nimodipine 60 mg PO q4h for 21 days to prevent delayed cerebral ischemia from vasospasm (it improves outcome but does not abolish the vasospasm itself).
Final Cram Sheet: Stroke Syndromes and Outcome Scales
Localization questions reward pattern recognition. Match the deficit to the vessel:
| Vessel / location | Hallmark deficits |
|---|---|
| MCA (middle cerebral) | Contralateral face/arm > leg weakness; aphasia (dominant) or neglect (nondominant); gaze toward lesion |
| ACA (anterior cerebral) | Contralateral leg > arm weakness; abulia |
| PCA (posterior cerebral) | Contralateral homonymous hemianopia; visual deficits |
| Vertebrobasilar / posterior | Vertigo, diplopia, dysarthria, ataxia, crossed signs; coma if basilar |
| Lacunar (small vessel) | Pure motor, pure sensory, ataxic-hemiparesis; NO cortical signs |
A key trap: the NIHSS under-scores posterior circulation strokes — a basilar occlusion can be devastating yet yield a low NIHSS, so do not rely on the score alone to triage posterior symptoms.
Outcome scales the SCRN must distinguish:
- NIHSS (0–42): acute severity; higher is worse. Used at the bedside hyperacutely and to track change.
- Modified Rankin Scale (mRS 0–6): functional disability/independence at follow-up. 0 = no symptoms; 1 = no significant disability; 2 = slight (independent in daily affairs); 3 = moderate (needs some help, walks unaided); 4 = moderately severe (cannot walk/attend needs unaided); 5 = severe (bedridden, incontinent, constant care); 6 = dead. A "good outcome" in trials is typically mRS 0–2.
Exam-Day Strategy and Complication Recall
Beyond the numbers, the SCRN rewards disciplined test technique. The 170-question (150 scored + 20 pretest), 3-hour computer-based format means ~1 minute per item — read efficiently and trust your preparation.
Strategy reminders:
- Identify the stroke type first (ischemic vs hemorrhagic; if ischemic, tPA candidate or not). The right BP/treatment answer flows from that classification.
- Anchor on time and the last-known-well, not symptom-discovery time, for window questions.
- Airway, breathing, dysphagia screen before PO anything — a recurring "what do you do first" answer.
- Watch for distractors that swap the numbers (CT ≤25 vs needle ≤60 vs puncture ≤90; ICH SBP ~140 vs ischemic 220/120).
High-yield complications to recall: hemorrhagic transformation after thrombolysis (sudden neuro decline, headache, BP spike → stop infusion, emergent CT, reverse), cerebral edema/increased ICP peaking days 2–5 in large infarcts, seizures, DVT/PE (hence STK-1 VTE prophylaxis), aspiration pneumonia (hence the swallow screen), and in SAH rebleeding, vasospasm, and hydrocephalus.
Post-stroke, screen for depression (affects 20–60% of survivors; SSRIs are first-line) and manage spasticity (stretching, splinting, and botulinum toxin A as first-line focal treatment). With these tables and patterns secured, you are ready for exam day.
A 70 kg patient is eligible for IV alteplase. What is the correct dosing approach?
A patient with acute ischemic stroke is NOT a thrombolytic candidate. Blood pressure is 196/104 mm Hg. What is the appropriate action?
Which presentation is most consistent with a lacunar (small-vessel) stroke rather than a large cortical stroke?
On the modified Rankin Scale (mRS), which score corresponds to slight disability where the patient is unable to do all previous activities but can look after their own affairs without assistance?
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