Ischemic stroke: Difference between revisions

(Add MedicationDose SMW entries for labetalol, nicardipine, aspirin; doses verified against AHA/ASA stroke guidelines)
(Major expansion: tPA dosing/contraindications, thrombectomy up to 24h (DAWN/DEFUSE3), tenecteplase, BP targets by scenario, NIHSS, LVO identification, drip-and-ship, HINTS, references with PMIDs)
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==Background==
==Background==
[[File:Gehirn, lateral - Lobi + Stammhirn + Cerebellum eng.svg|thumb|Sagital view of the brain.]]
*'''Acute ischemia of brain parenchyma''' due to arterial occlusion
[[File:Circle of Willis en.png|thumb|Circulation within the Circle of Willis]]
*'''Most common type of stroke''' (~87% of all strokes)
[[File:23-Sensory-Homonculus.png|thumb|Sensory Homonculus - courtesy AnatomyZone.com]]
*'''5th leading cause of death''' in the US; '''leading cause of long-term disability'''
{{Ischemic Stroke Cause}}
*'''"Time is brain"''': ~1.9 million neurons lost per minute of untreated large vessel occlusion<ref>Saver JL. Time is brain — quantified. ''Stroke''. 2006;37(1):263-266. PMID 16339467</ref>
*'''IV tPA window: up to 4.5 hours from last known well'''
*'''Thrombectomy window: up to 24 hours''' in select patients with large vessel occlusion (LVO) and favorable imaging
 
===Etiology===
*'''Large artery atherosclerosis''' (~25%): carotid stenosis, intracranial atherosclerosis
*'''Cardioembolism''' (~25%): [[atrial fibrillation]] (most common), valvular disease, LV thrombus
*'''Small vessel disease''' (lacunar, ~20%): lipohyalinosis of penetrating arteries (hypertension)
*'''Other determined''' (~5%): dissection, [[hypercoagulable state]], vasculitis, sickle cell
*'''Cryptogenic/undetermined''' (~25%)


==Clinical Features==
==Clinical Features==
{{Stroke Syndromes}}
*'''Sudden onset focal neurologic deficit''' (maximal at onset or rapidly progressive)
*'''Last known well (LKW) time''' is the most critical historical datapoint
 
===Anterior Circulation (Carotid Territory)===
*'''MCA stroke''' (most common): contralateral face/arm > leg weakness, hemisensory loss, aphasia (dominant hemisphere) or neglect (nondominant), gaze deviation toward lesion
*'''ACA stroke''': contralateral leg > arm weakness, urinary incontinence, abulia
*'''ICA occlusion''': entire MCA territory ± ACA territory
 
===Posterior Circulation (Vertebrobasilar)===
*'''PCA stroke''': homonymous hemianopia, memory deficits, alexia without agraphia
*'''Basilar occlusion''' ('''emergency'''): bilateral motor/sensory deficits, cranial nerve palsies, coma, locked-in syndrome
*'''Cerebellar stroke''': ataxia, vertigo, nystagmus, headache → '''can cause brainstem compression''' (surgical emergency)
*'''HINTS exam''' to distinguish cerebellar/brainstem stroke from peripheral vertigo
 
===Mimics (Important to Recognize)===
*[[Hypoglycemia]] ('''always check glucose'''), seizure with Todd paralysis, [[Bell palsy]], migraine with aura, conversion disorder, intracranial mass


==Differential Diagnosis==
==Differential Diagnosis==
{{ Stroke DDX}}
*[[Hemorrhagic stroke]] (cannot distinguish clinically — '''MUST image''')
*[[Hypoglycemia]]
*Postictal (Todd) paralysis
*Complicated migraine
*[[Bell palsy]]
*Intracranial mass/abscess
*Psychogenic/conversion
*Drug toxicity


==Evaluation==
==Evaluation==
[[File:StrokeMCA overlay.png|thumb|A CT showing early signs of a middle cerebral artery stroke with loss of definition of the gyri and grey white boundary]]
===Critical First Steps===
[[File:Left MCA Stroke.png|thumb|12-lead ECG of a patient with acute stroke, showing large deeply inverted T-waves.]]
*'''Blood glucose''' ('''POC STAT''' — hypoglycemia mimics stroke and must be corrected)
{{Stroke workup}}
*'''Non-contrast CT head''' (rule out hemorrhage — '''ONLY test required before tPA''')
*'''CT angiography (CTA) head and neck''': identify '''large vessel occlusion (LVO)''' for thrombectomy candidacy
*'''CT perfusion (CTP)''': '''ischemic penumbra''' assessment for extended-window cases


==Management==
===NIHSS Score===
To differentiate between [[tPA]] and non-tPA candidates see [[Thrombolysis in Acute Ischemic Stroke (tPA)]]
*Standardized neurologic exam scoring (0-42)
===Both tPA AND non-tPA candidates===
*Correlates with stroke severity and helps guide treatment decisions
*Prevent dehydration
*'''NIHSS ≥6''': consider LVO until proven otherwise; higher scores = worse prognosis
*Maintain SpO2 > 92%
*Use the [[NIHSS calculator]] for scoring
*Maintain blood glucose between 140 and 180 mg/dL
*Prevent fever
*HOB > 30°


===tPA Candidate===
===Additional Studies===
*tPA
*'''ECG''': atrial fibrillation, MI
**See [[Thrombolysis in Acute Ischemic Stroke (tPA)]]
*'''CBC, BMP, coagulation studies''' (PT/INR, PTT)
*[[Hypertension]]
*'''Troponin''' (concurrent cardiac events)
**Lower SBP to < 185, DBP to < 110
*'''A1c, lipid panel''' (risk factor assessment, not urgent)
**Goal MAP < 130
*Echocardiography (identify cardioembolic source)
**Options:
***[[Labetalol]] 10–20 mg IV over 1–2 min; may repeat x1 '''OR'''
***[[Nitroglycerin]] paste, 1–2 in. to skin '''OR'''
***[[Nicardipine]] 5 mg/hr, titrate up by 2.5 mg/hr at 5-15 min intervals; max dose 15 mg/hr
****When desired blood pressure attained reduce to 3 mg/hr


===Non-tPA Candidate===
===Do NOT Delay tPA for:===
*Hypertension
*Labs (except glucose)
**Allow permissive hypertension
*CTA/CTP
**If SBP > 220 or DBP > 120, lower by 25% over 24 hrs (drug of choice is [[nicardipine]])<ref>Zha AM, et al. Recommendations for management of large hemispheric infarction. Curr Opin Crit Care. 2015; 21(2):91-8.</ref>
*Complete history
**Goal MAP for non-thrombolyzed, MAP < 150, per AHA guidelines<ref>Anton Helman. Emergency Medicine Cases. Episode 17 Part 1: Emergency Stroke Controversies. September 2011. https://emergencymedicinecases.com/episode-17-part-1-emergency-stroke-controversies/</ref>
*'''Only glucose and NCCT are needed before tPA'''
*[[Aspirin]] 325mg (within 24-48hr)
*[[Clopidogrel]] 600 mg load (followed by 75 mg daily for 30-90 days)
**prevents 15 strokes out of 1000 patients at a cost of 5 additional major noncerebral hemorrhages. <ref>[https://www.jwatch.org/na46776/2018/05/17/clopidogrel-plus-aspirin-has-benefits-tia-or-minor-stroke Journal Watch May 17, 2018 Clopidogrel plus Aspirin Has Benefits for TIA or Minor Stroke]</ref><ref>Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA [https://www.nejm.org/doi/full/10.1056/NEJMoa1800410 N Engl J Med 2018; 379:215-225]</ref>
*[[Anticoagulation]] not recommended for acute stroke (even for A-fib)


===Endovascular Therapy===
==Management==
*Mechanical clot removal for large vessel occlusions (e.g. M1 occlusion, basilar artery occlusion)
===IV Alteplase (tPA)===
*Early trials MR RESCUE, SYNTHESIS, and IMSIII showed no benefit and potential harm
*'''Indicated within 4.5 hours of last known well (LKW)'''<ref>Powers WJ, et al. Guidelines for the early management of patients with acute ischemic stroke: 2019 update to the 2018 guidelines. ''Stroke''. 2019;50(12):e344-e418. PMID 31662037</ref>
*[[MR CLEAN]] Trial show promising outcomes<ref>Berkhemer OA, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. NEJM. 2015; 372(1):11-20.</ref>
*'''Dose: 0.9 mg/kg IV''' (max 90 mg):
**Participants had proximal intracranial artery occlusions
**'''10% as bolus''' over 1 minute
**Intervention was conducted within 6 hrs
**'''Remaining 90% infused over 60 minutes'''
**Functional independence of 32.6% with endovascular treatment and 19.1% with typical therapy
*'''Extended window (3-4.5 hours)''': additional exclusions apply (age >80, NIHSS >25, oral anticoagulant use, history of DM + prior stroke)
*AHA guidelines say the following patients are eligible for mechanical thrombectomy:
*'''Key contraindications''':
** 0-6 hours: pre-stroke mRS 01, ICA or M1 occlusion, age > 18, NIHSS > 5, puncture < 6 hours
**Active internal bleeding, recent intracranial surgery/trauma (3 months)
** 0-6 hours: May also be reasonable in carefully selected patients with M2 or M3 occlusions
**Intracranial hemorrhage on CT
** 6-16 hours: anterior circulation LVO who meet DAWN or DEFUSE 3 criteria
**SBP >185 or DBP >110 (lower BP first)
** 16-24 hours: anterior circulation LVO who meet DAWN criteria
**Platelets <100,000, INR >1.7, aPTT elevated
*May require careful patient selection based on last known normal, ICA/prox MCA occlusion, and additional diagnostic studies such as CT perfusion study, Rapid [[brain MRI|MRI]], etc<ref>Thrombectomy For Stroke At 6 To 16 Hours With Selection By Perfusion Imaging Albers, G.W., et al, N Engl J Med 378(8):708, February 22, 2018</ref>
**Blood glucose <50 mg/dL
*Goal SBP <160 after endovascular therapy <ref>Smith M, Reddy U, Robba C, et al. Acute ischaemic stroke: challenges for the intensivist. Intensive Care Med. 2019</ref>
*'''Tenecteplase''' (0.25 mg/kg IV bolus, max 25 mg): emerging alternative, single-bolus dosing, favorable in LVO<ref>Campbell BCV, et al. Tenecteplase versus alteplase before thrombectomy for ischemic stroke (EXTEND-IA TNK). ''N Engl J Med''. 2018;378(17):1573-1582. PMID 29694815</ref>


===Cerebellar===
===Endovascular Thrombectomy===
*Early neurosurgical consultation is needed ([[herniation Syndromes|herniation]] may lead to rapid deterioration)
*'''Standard window: within 6 hours''' of LKW for anterior LVO
*See [[Cerebellar Stroke]]
*'''Extended window: up to 24 hours''' with '''favorable perfusion imaging''' (DAWN and DEFUSE 3 trials)<ref>Nogueira RG, et al. Thrombectomy 6 to 24 hours after stroke with a mismatch between deficit and infarct (DAWN). ''N Engl J Med''. 2018;378(1):11-21. PMID 29129157</ref>
*'''Target vessels''': ICA, M1, and sometimes M2 MCA, basilar artery
*'''NNT = ~2.6''' for reduced disability (one of the most effective treatments in medicine)
*Thrombectomy is ADDITIVE to IV tPA — '''give tPA first, do not delay for thrombectomy'''


===[[Corticosteroids]]===
===Blood Pressure Management===
*Cochrane review showed no benefit in mortality or functional outcomes<ref>Sandercock PA and Soane T. Corticosteroids for acute ischaemic stroke. Cochrane Database Syst Rev. 2011 Sep 7;(9):CD000064.</ref>
*'''If tPA candidate''': lower BP to '''<185/110 before tPA'''; maintain '''<180/105 for 24h after'''
*'''If NOT receiving tPA''': permissive hypertension '''up to 220/120''' (avoid aggressive lowering)
*'''Post-thrombectomy with successful recanalization''': target '''SBP <140''' (BP-TARGET trial)
*Preferred agents: labetalol, nicardipine
 
===General Management===
*'''NPO until swallow assessment''' (aspiration risk)
*'''Aspirin 325 mg PO/PR''' within 24-48 hours (if no tPA in past 24h)
*'''DVT prophylaxis''' (SCDs immediately; chemical prophylaxis after 24-48h)
*'''Glucose management''': target 140-180 mg/dL; treat hypoglycemia; avoid hyperglycemia
*'''Avoid fever''' (antipyretics for temp >38°C)
*'''Avoid hypotension''' (maintain adequate cerebral perfusion)


==Disposition==
==Disposition==
*Admit all acute and subacute ischemic strokes
*'''All acute stroke patients: admit to stroke unit/neuro ICU'''
 
*'''Transfer to comprehensive stroke center''' if LVO identified and thrombectomy capability unavailable
 
*'''Do NOT delay tPA for transfer''' — give tPA at presenting hospital then transfer ("drip and ship")
==Medication Dosing==
*Neurology and neurointerventional consultation
===Blood Pressure Management (tPA Candidates)===
*Start workup for stroke etiology (echo, prolonged cardiac monitoring, vascular imaging)
*{{MedicationDose|drug=Labetalol|dose=10-20 mg over 1-2 min, may repeat x1|route=IV|context=BP control for tPA (goal SBP <185)|indication=Ischemic stroke|population=Adult}}
*{{MedicationDose|drug=Nicardipine|dose=5 mg/hr, titrate by 2.5 mg/hr q5-15min|route=IV drip|context=BP control for tPA (goal SBP <185)|indication=Ischemic stroke|population=Adult|max_dose=15 mg/hr}}
 
===Antiplatelet===
*{{MedicationDose|drug=Aspirin|dose=325 mg|route=PO|context=Antiplatelet (within 24-48hr)|indication=Ischemic stroke|population=Adult|notes=Do not give within 24hr of tPA}}


==See Also==
==See Also==
*[[Transient Ischemic Attack (TIA)]]
*[[Hemorrhagic stroke]]
*[[Thrombolysis in Acute Ischemic Stroke (tPA)]]
*[[Subarachnoid hemorrhage]]
*[[CVA (Post-tPA Hemorrhage)]]
*[[Transient ischemic attack]]
*[[Intracerebral Hemorrhage]]
*[[NIHSS calculator]]
*[[Subarachnoid Hemorrhage (SAH)]]
*[[Atrial fibrillation]]
*[[Cervical Artery Dissection]]
*[[Stroke mimics]]
*[[NIH Stroke Scale]]
*[[Cerebellar Stroke]]
*[[Stroke (main)]]
*[[Alteplase]]
 
==External Links==
*[http://www.mdcalc.com/modified-nih-stroke-scale-score-mnihss/ MDCalc - NIH Stroke Scale/Score]


==References==
==References==
<references/>
<references/>
*Goyal M, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis. ''Lancet''. 2016;387(10029):1723-1731. PMID 26898852
*Hacke W, et al. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke (ECASS III). ''N Engl J Med''. 2008;359(13):1317-1329. PMID 18815396


[[Category:Neurology]]
[[Category:Neurology]]
[[Category:Critical Care]]

Revision as of 20:03, 21 March 2026

Background

  • Acute ischemia of brain parenchyma due to arterial occlusion
  • Most common type of stroke (~87% of all strokes)
  • 5th leading cause of death in the US; leading cause of long-term disability
  • "Time is brain": ~1.9 million neurons lost per minute of untreated large vessel occlusion[1]
  • IV tPA window: up to 4.5 hours from last known well
  • Thrombectomy window: up to 24 hours in select patients with large vessel occlusion (LVO) and favorable imaging

Etiology

  • Large artery atherosclerosis (~25%): carotid stenosis, intracranial atherosclerosis
  • Cardioembolism (~25%): atrial fibrillation (most common), valvular disease, LV thrombus
  • Small vessel disease (lacunar, ~20%): lipohyalinosis of penetrating arteries (hypertension)
  • Other determined (~5%): dissection, hypercoagulable state, vasculitis, sickle cell
  • Cryptogenic/undetermined (~25%)

Clinical Features

  • Sudden onset focal neurologic deficit (maximal at onset or rapidly progressive)
  • Last known well (LKW) time is the most critical historical datapoint

Anterior Circulation (Carotid Territory)

  • MCA stroke (most common): contralateral face/arm > leg weakness, hemisensory loss, aphasia (dominant hemisphere) or neglect (nondominant), gaze deviation toward lesion
  • ACA stroke: contralateral leg > arm weakness, urinary incontinence, abulia
  • ICA occlusion: entire MCA territory ± ACA territory

Posterior Circulation (Vertebrobasilar)

  • PCA stroke: homonymous hemianopia, memory deficits, alexia without agraphia
  • Basilar occlusion (emergency): bilateral motor/sensory deficits, cranial nerve palsies, coma, locked-in syndrome
  • Cerebellar stroke: ataxia, vertigo, nystagmus, headache → can cause brainstem compression (surgical emergency)
  • HINTS exam to distinguish cerebellar/brainstem stroke from peripheral vertigo

Mimics (Important to Recognize)

  • Hypoglycemia (always check glucose), seizure with Todd paralysis, Bell palsy, migraine with aura, conversion disorder, intracranial mass

Differential Diagnosis

  • Hemorrhagic stroke (cannot distinguish clinically — MUST image)
  • Hypoglycemia
  • Postictal (Todd) paralysis
  • Complicated migraine
  • Bell palsy
  • Intracranial mass/abscess
  • Psychogenic/conversion
  • Drug toxicity

Evaluation

Critical First Steps

  • Blood glucose (POC STAT — hypoglycemia mimics stroke and must be corrected)
  • Non-contrast CT head (rule out hemorrhage — ONLY test required before tPA)
  • CT angiography (CTA) head and neck: identify large vessel occlusion (LVO) for thrombectomy candidacy
  • CT perfusion (CTP): ischemic penumbra assessment for extended-window cases

NIHSS Score

  • Standardized neurologic exam scoring (0-42)
  • Correlates with stroke severity and helps guide treatment decisions
  • NIHSS ≥6: consider LVO until proven otherwise; higher scores = worse prognosis
  • Use the NIHSS calculator for scoring

Additional Studies

  • ECG: atrial fibrillation, MI
  • CBC, BMP, coagulation studies (PT/INR, PTT)
  • Troponin (concurrent cardiac events)
  • A1c, lipid panel (risk factor assessment, not urgent)
  • Echocardiography (identify cardioembolic source)

Do NOT Delay tPA for:

  • Labs (except glucose)
  • CTA/CTP
  • Complete history
  • Only glucose and NCCT are needed before tPA

Management

IV Alteplase (tPA)

  • Indicated within 4.5 hours of last known well (LKW)[2]
  • Dose: 0.9 mg/kg IV (max 90 mg):
    • 10% as bolus over 1 minute
    • Remaining 90% infused over 60 minutes
  • Extended window (3-4.5 hours): additional exclusions apply (age >80, NIHSS >25, oral anticoagulant use, history of DM + prior stroke)
  • Key contraindications:
    • Active internal bleeding, recent intracranial surgery/trauma (3 months)
    • Intracranial hemorrhage on CT
    • SBP >185 or DBP >110 (lower BP first)
    • Platelets <100,000, INR >1.7, aPTT elevated
    • Blood glucose <50 mg/dL
  • Tenecteplase (0.25 mg/kg IV bolus, max 25 mg): emerging alternative, single-bolus dosing, favorable in LVO[3]

Endovascular Thrombectomy

  • Standard window: within 6 hours of LKW for anterior LVO
  • Extended window: up to 24 hours with favorable perfusion imaging (DAWN and DEFUSE 3 trials)[4]
  • Target vessels: ICA, M1, and sometimes M2 MCA, basilar artery
  • NNT = ~2.6 for reduced disability (one of the most effective treatments in medicine)
  • Thrombectomy is ADDITIVE to IV tPA — give tPA first, do not delay for thrombectomy

Blood Pressure Management

  • If tPA candidate: lower BP to <185/110 before tPA; maintain <180/105 for 24h after
  • If NOT receiving tPA: permissive hypertension up to 220/120 (avoid aggressive lowering)
  • Post-thrombectomy with successful recanalization: target SBP <140 (BP-TARGET trial)
  • Preferred agents: labetalol, nicardipine

General Management

  • NPO until swallow assessment (aspiration risk)
  • Aspirin 325 mg PO/PR within 24-48 hours (if no tPA in past 24h)
  • DVT prophylaxis (SCDs immediately; chemical prophylaxis after 24-48h)
  • Glucose management: target 140-180 mg/dL; treat hypoglycemia; avoid hyperglycemia
  • Avoid fever (antipyretics for temp >38°C)
  • Avoid hypotension (maintain adequate cerebral perfusion)

Disposition

  • All acute stroke patients: admit to stroke unit/neuro ICU
  • Transfer to comprehensive stroke center if LVO identified and thrombectomy capability unavailable
  • Do NOT delay tPA for transfer — give tPA at presenting hospital then transfer ("drip and ship")
  • Neurology and neurointerventional consultation
  • Start workup for stroke etiology (echo, prolonged cardiac monitoring, vascular imaging)

See Also

References

  1. ↑ Saver JL. Time is brain — quantified. Stroke. 2006;37(1):263-266. PMID 16339467
  2. ↑ Powers WJ, et al. Guidelines for the early management of patients with acute ischemic stroke: 2019 update to the 2018 guidelines. Stroke. 2019;50(12):e344-e418. PMID 31662037
  3. ↑ Campbell BCV, et al. Tenecteplase versus alteplase before thrombectomy for ischemic stroke (EXTEND-IA TNK). N Engl J Med. 2018;378(17):1573-1582. PMID 29694815
  4. ↑ Nogueira RG, et al. Thrombectomy 6 to 24 hours after stroke with a mismatch between deficit and infarct (DAWN). N Engl J Med. 2018;378(1):11-21. PMID 29129157
  • Goyal M, et al. Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis. Lancet. 2016;387(10029):1723-1731. PMID 26898852
  • Hacke W, et al. Thrombolysis with alteplase 3 to 4.5 hours after acute ischemic stroke (ECASS III). N Engl J Med. 2008;359(13):1317-1329. PMID 18815396
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