1. Stroke (Acute Ischemic Stroke)

Quick Recap

Neurology System, Protocol 1/12. Acute Ischemic Stroke.

1. Definition & Presentation

Ischemic stroke = sudden inadequate perfusion to a brain region causing neuronal death/irreversible damage. Presentation varies by territory — from subtle sensory loss to major motor/speech deficits; thalamic and brainstem infarcts can cause altered mental status difficult to distinguish from metabolic/infectious encephalopathy.

Stroke mimics (must be excluded, always requires CT/MRI): intracranial hemorrhage, neoplasm/abscess, postictal (Todd's) paralysis, complicated migraine, metabolic derangement (hypo/hyperglycemia), psychosomatic disorders.

2. Immediate Stabilization (ABCDE)

Airway/Breathing: protect airway if depressed consciousness/bulbar dysfunction; minimize permissive hypercapnia — rising CO2 dilates cerebral vessels/arterioles, raising ICP, which is detrimental with cerebral edema complicating large strokes.

Circulation — BP management is central and DIFFERS from standard hypertensive emergency approach:

• NOT thrombolysis/thrombectomy candidate: tolerate BP up to 220/120 mmHg for the first 24-48h (reactive hypertension helps perfuse the ischemic penumbra) UNLESS evidence of ongoing end-organ damage elsewhere (AMI, aortic dissection, HF, renal failure) — do NOT aggressively lower BP in uncomplicated ischemic stroke
• Thrombolysis candidate (before administration): lower BP to <185/110 mmHg
• Post-thrombolysis or post-thrombectomy recanalization: keep SBP <180 and DBP <105 mmHg for the first 24h to avoid hemorrhagic transformation
• Preferred agents: IV beta-blockers or calcium channel blockers (short-acting, rapidly titratable); avoid nitrates — cerebral vasodilation risks worsening edema
• Induced hypertension to salvage penumbra is controversial/debated — reserve for cases with a clear temporal relationship between clinical deterioration and low BP

Disability: NIHSS scoring, glucose check (hypo/hyperglycemia are stroke mimics and worsen outcomes if uncorrected).

Checklist:

3. IV Thrombolysis — Indications and Contraindications

Indications: acute focal neurologhic deficit in a defined vascular territory; clearly defined onset <3 or 4.5h prior to treatment (if wake-up stroke, onset = "last seen normal"); age >=18; no ICH/non-vascular lesion/advanced infarction signs (sulcal edema, hemispheric swelling, large low-attenuation areas) on CT.

Key contraindications (not exhaustive — full list is extensive): onset beyond window; rapidly improving/mild nondisabling symptoms (relative); seizure at onset (relative); SAH-suggestive presentation regardless of CT; SBP >185 or DBP >110 resistant to treatment; ischemic stroke within 3 months; prior ICH/SAH with substantial recurrence risk; >10 cerebral microbleeds on MRI; untreated aneurysm >=10mm or AVM; GI/GU hemorrhage within 21 days; GI malignancy; noncompressible arterial puncture within 7 days; LP within 7 days (relative); aortic arch dissection; major surgery/trauma within 14 days (relative); intracranial/intraspinal surgery within 3 months; intra-axial neoplasm; acute or severe (within 3 months) head injury; recent MI (relative); acute pericarditis (relative); infective endocarditis; therapeutic oral anticoagulation (warfarin, DOACs); heparin within 48h/LMWH within 24h; tPA within 7 days previously; hemorrhagic diathesis; glucose <50 or >400; platelets <100,000; INR >1.7 or elevated aPTT; pregnancy (relative). Additional for the 3-4.5h extended window: NIHSS >25 excludes.

Prior aspirin/dual antiplatelet therapy is NOT a contraindication to thrombolysis.

Critically ill patients with multiple organ failure are seldom candidates — thrombocytopenia, coagulopathy, active bleeding, and inability to establish last-known-normal time are common exclusions in this population specifically.

Agents: alteplase or tenecteplase, administered as fast as possible within the window for maximal benefit.

Monitoring post-thrombolysis: 24 hours of observation for ICH (Section 6) and orolingual angioedema; any new neurologic change should prompt immediate repeat brain imaging.

4. Mechanical Thrombectomy

Offered to select patients with large vessel occlusion, up to 24 hours from symptom onset — CT perfusion or MRI with perfusion/diffusion-weighted imaging determines extended-window (6-24h) candidacy by identifying salvageable penumbra vs completed infarct core.

5. Post-Stroke General Critical Care

Standard ICU supportive care (acid-base, oxygenation, euvolemia, glycemic control) PLUS stroke-specific considerations:

• Fever worsens outcomes — active temperature control indicated
• Antiplatelet therapy: give aspirin (or another antiplatelet) within 24-48h of thrombolysis administration
• Avoid dual antiplatelet therapy (aspirin + clopidogrel) in the immediate poststroke period absent a strong cardiac/cerebrovascular indication — increases intra- and extracranial hemorrhage risk
• Heparin is NO LONGER recommended for acute ischemic stroke treatment — rare exceptions exist (cardiac or carotid artery thrombus)
• Therapeutic anticoagulation for AFib-related secondary prevention is generally deferred 3-14 days poststroke (timing depends on infarct size) given hemorrhagic conversion risk — do not start acutely
• VTE prophylaxis should start as soon as feasible; enoxaparin is superior to unfractionated heparin for DVT prevention (not PE prevention)
• Seizure prophylaxis is NOT indicated in ischemic stroke — phenytoin and valproic acid have actually been shown to WORSEN outcomes; suspected seizures should be evaluated with EEG and treated per the Status Epilepticus protocol only if they occur

6. Post-Thrombolysis Complications (Reference Tables)

Post-thrombolysis intracranial hemorrhage:

1. Stop IV tPA infusion immediately
2. Emergent CT head
3. CBC, PT/INR, aPTT, fibrinogen, type and crossmatch
4. Treat elevated BP; monitor/treat hyperglycemia
5. Consider reversal: cryoprecipitate 10U over 1h (repeat if fibrinogen <150), OR tranexamic acid 1000mg IV over 1h, OR epsilon-aminocaproic acid 4-5g over 20min
6. Neurosurgical consultation

Orolingual angioedema (alteplase reaction):

1. Stop IV tPA infusion
2. Monitor airway, low threshold for intubation
3. IV diphenhydramine 50mg + IV ranitidine 50mg + IV methylprednisolone 125mg
4. If worsening: epinephrine 0.3mL SC or 0.5mL nebulized
5. Avoid ACE inhibitors going forward

7. Cerebral Edema and Malignant Infarction

Highest risk: large cerebral/cerebellar infarctions, and YOUNGER patients (less age-related cerebral atrophy/reserve space) — requires close monitoring and aggressive intervention readiness rather than the reassurance one might apply to an elderly patient with more cranial "reserve."

Cerebellar infarction with brainstem compression/obstructive hydrocephalus: treat with decompressive suboccipital craniectomy + CSF diversion via ventriculostomy.

Malignant MCA infarction (supratentorial): decompressive hemicraniectomy is a systematically reviewed, evidence-supported option in appropriate candidates (younger patients, appropriately timed) — see Raised ICP protocol for full herniation management framework.

Bridging measure for acute decompensation with edema/herniation signs: brief period of hyperventilation as a TEMPORIZING bridge to definitive surgical/CSF-diversion therapy — not a standalone strategy.

8. Determining Stroke Etiology (Secondary Prevention Workup)

Telemetry (paroxysmal AFib detection), echocardiography (cardioembolic source, PFO), brain MRI, carotid Doppler, intracranial vascular imaging — increasing complexity of modern stroke algorithms warrants stroke specialist involvement rather than a one-size-fits-all secondary prevention approach (the old universal-anticoagulation/universal-endarterectomy paradigm has given way to more individualized algorithms).

9. Consultation Matrix

10. Monitoring Framework

Serial NIHSS, continuous neuro checks (especially first 24h post-thrombolysis), BP per candidacy-specific target, glucose, temperature (active control), watch for new deficit -> immediate repeat imaging.

11. Complications

Hemorrhagic transformation (spontaneous or post-thrombolysis), malignant cerebral edema/herniation, orolingual angioedema (thrombolysis-specific), seizure, aspiration pneumonia, DVT/PE. Prevention: candidacy-appropriate BP targets, avoiding dual antiplatelet without indication, avoiding seizure-prophylaxis drugs known to worsen outcomes, early VTE prophylaxis. Rescue: reversal protocol for post-thrombolysis ICH, decompressive surgery for malignant edema, airway management for angioedema.

12. Escalation & De-escalation

Escalate: new neurologic deterioration -> immediate repeat imaging, consider hemorrhagic transformation or edema/herniation; malignant edema signs -> neurosurgery, consider decompressive surgery.

De-escalate: neurologically stable/improving, BP at goal, no hemorrhagic transformation -> transition BP target toward standard long-term goals, initiate antiplatelet/anticoagulation per timing guidance, begin rehabilitation planning.

13. ICU Discharge Criteria

Neurologically stable or improving, BP controlled per stroke-appropriate target transitioning to long-term goal, no evidence of hemorrhagic transformation, secondary prevention workup underway/antiplatelet or anticoagulation plan established, rehabilitation/swallowing assessment completed, VTE prophylaxis in place.

14. Documentation & Medicolegal Checklist

15. Key Guidelines

Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the early management of patients with acute ischemic stroke, and 2019 update (AHA/ASA, Stroke 2018/2019) — primary reference; note stroke guidelines update frequently, verify current edition.

16. Landmark Evidence

Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke (AHA/ASA Stroke Council, Stroke 2007) — foundational. Del Zoppo GJ, Saver JL, Jauch EC, et al. Expansion of the time window for tPA (AHA/ASA science advisory, Stroke 2009) — established the extended 3-4.5h window. Gupta R, Connolly ES, Mayer S, et al. Hemicraniectomy for massive MCA territory infarction: systematic review. Stroke. 2004;35:539-543 — evidence base for decompressive hemicraniectomy candidacy.

17. Controversies

Induced hypertension to salvage the ischemic penumbra is explicitly debated and not routine — reserved for cases with clear deterioration-BP correlation. The precise threshold and patient selection for decompressive hemicraniectomy (age cutoffs, timing) continues to be refined beyond the foundational systematic review evidence. Extended-window thrombectomy candidacy (6-24h) relies on perfusion imaging interpretation that has some inter-institutional variability in protocol and threshold.

18. References

1. Approach to Ischemic Stroke chapter. Washington Manual of Critical Care, 4th ed, 2025 (Ch. 55).
2. Powers WJ, Rabinstein AA, Ackerson T, et al. 2018 Guidelines for the early management of patients with acute ischemic stroke. Stroke. 2018;49(3):e46-e99.
3. Powers WJ, Rabinstein AA, Ackerson T, et al. 2019 update to the 2018 guidelines for early management of acute ischemic stroke. Stroke. 2019;50(12):e344-e418.
4. Adams HP Jr, del Zoppo G, Alberts MJ, et al. Guidelines for the early management of adults with ischemic stroke. Stroke. 2007;38:1655-1711.
5. Del Zoppo GJ, Saver JL, Jauch EC, et al. Expansion of the time window for treatment of acute ischemic stroke with IV tPA. Stroke. 2009;40:2945-2948.
6. Gupta R, Connolly ES, Mayer S, et al. Hemicraniectomy for massive middle cerebral artery territory infarction: a systematic review. Stroke. 2004;35:539-543.