Ischemic stroke

Background

Sensory Homonculus - courtesy AnatomyZone.com

Ischemic stroke causes (87% of all strokes)

Clinical Features

Anterior Circulation

  • Blood supply via internal carotid system
  • Includes ACA and MCA

Internal Carotid Artery

  • Tonic gaze deviation towards lesion
  • Global aphasia, dysgraphia, dyslexia, dyscalculia, disorientation (dominant lesion)
  • Spatial or visual neglect (non-dominant lesion)

Anterior Cerebral Artery (ACA)

Signs and Symptoms:

  • Contralateral sensory and motor symptoms in the lower extremity (sparing hands/face)
  • Urinary and bowel incontinence
  • Left sided lesion: akinetic mutism, transcortical motor aphasia
  • Right sided lesion: Confusion, motor hemineglect
  • Presence of primitive grasp and suck reflexes
  • May manifest gait apraxia

Middle Cerebral Artery (MCA)

Signs and Symptoms:

  • Hemiparesis, facial plegia, sensory loss contralateral to affected cortex
  • Motor deficits found more commonly in face and upper extremity than lower extremity
  • Dominant hemisphere involved: aphasia
    • Wernicke's aphasia (receptive aphasia) -> patient unable to process sensory input and don't understand verbal communication
    • Broca's aphasia (expressive aphasia) -> patient unable to communicate verbally, even though understanding may be intact
  • Nondominant hemisphere involved: dysarthria (motor deficit of the mouth and speech muscles; understanding intact) w/o aphasia, inattention and neglect side opposite to infarct
  • Contralateral homonymous hemianopsia
  • Gaze preference toward side of infarct
  • Agnosia (inability to recognize previously known subjects)

Posterior circulation

Signs and Symptoms:

Basilar artery

Signs and Symptoms:

  • Quadriplegia, coma, locked-in syndrome
  • "Crossed signs" in which a patient has unilateral cranial nerve deficits but contralateral hemiparesis and hemisensory loss suggest brainstem infarction
    • Millard-Gubler syndrome (ventral pontine syndrome) -- ipsilateral CN VI and VII palsy with contralateral hemiplegia of extremities
  • Sparing of vertical eye movements (CN III exits brainstem just above lesion)
    • Thus, may also have miosis b/l
  • One and a half syndrome (seen in a variety of brainstem infarctions)
    • "Half" - INO (internuclear ophthalmoplegia) in one direction
    • "One" - inability for conjugate gaze in other direction
    • Convergence and vertical EOM intact
  • Medial inferior pontine syndrome (paramedian basilar artery branch)
    • Ipsilateral conjugate gaze towards lesion (PPRF), nystagmus (CN VIII), ataxia, diplopia on lateral gaze (CN VI)
    • Contralateral face/arm/leg paralysis and decreased proprioception
  • Medial midpontine syndrome (paramedian midbasilar artery branch)
    • Ipsilateral ataxia
    • Contralateral face/arm/leg paralysis and decreased proprioception
  • Medial superior pontine syndrome (paramedian upper basilar artery branches)
    • Ipsilateral ataxia, INO, myoclonus of pharynx/vocal cords/face
    • Contralateral face/arm/leg paralysis and decreased proprioception

Superior Cerebellar Artery (SCA)

Posterior Cerebral Artery (PCA)

Signs and Symptoms:

  • Common after CPR, as occipital cortex is a watershed area
  • Unilateral headache (most common presenting complaint)
  • Visual field defects (contralateral homonymous hemianopsia, unilateral blindness)
  • Visual agnosia - can't recognize objects
  • Possible macular sparing if MCA unaffected
  • Motor function is typically minimally affected
  • Lateral midbrain syndrome (penetrating arteries from PCA)
    • Ipsilateral CN III - eye down and out, pupil dilated
    • Contralateral hemiataxia, tremor, hyperkinesis (red nucleus)
  • Medial midbrain syndrome (upper basilar and proximal PCA)
    • Ipsilateral CN III - eye down and out, pupil dilated
    • Contralateral paralysis of face, arm, leg (corticospinal)

Anterior Inferior Cerebellar Artery (AICA)

Posterior Inferior Cerebellar Artery (PICA)

Signs and Symptoms:

  • Lateral medullary/Wallenberg syndrome
  • Ipsilateral cerebellar signs, ipsilateral loss of pain/temperature of face, ipsilateral Horner syndrome, ipsilateral dysphagia and hoarseness, dysarthria, vertigo/nystagmus
  • Contralateral loss of pain/temp over body
  • Also caused by vertebral artery occlusion (most cases)

Internal Capsule and Lacunar Infarcts

  • May present with either lacunar c/l pure motor or c/l pure sensory (of face and body)[3]
    • Pure c/l motor - posterior limb of internal capsule infarct
    • Pure c/l sensory - thalamic infarct (Dejerine and Roussy syndrome)
  • C/l motor plus sensory if large enough
  • Clinically to cortical large ACA + MCA stroke - the following signs suggest cortical rather than internal capsule[4]:
    • Gaze preference
    • Visual field defects
    • Aphasia (dominant lesion, MCA)
    • Spatial neglect (non-dominant lesion)
  • Others
    • Ipsilateral ataxic hemiparesis, with legs worse than arms - posterior limb of internal capsule infarct
    • Dysarthria/Clumsy Hand Syndrome - basilar pons or anterior limb of internal capsule infarct

Anterior Spinal Artery (ASA)

Superior ASA

  • Medial medullary syndrome - displays alternating pattern of sidedness of symptoms below
  • Contralateral arm/leg weakness and proprioception/vibration
  • Tongue deviation towards lesion

Inferior ASA

  • ASA syndrome
  • Watershed area of hypoperfusion in T4-T8
  • Bilateral pain/temp loss in trunk and extremities (spinothalamic)
  • Bilateral weakness in trunk and extremities (corticospinal)
  • Preservation of dorsal columns

Differential Diagnosis

Stroke-like Symptoms

Evaluation

A CT showing early signs of a middle cerebral artery stroke with loss of definition of the gyri and grey white boundary
12-lead ECG of a patient with acute stroke, showing large deeply inverted T-waves.

Stroke Work-Up

  • Labs
    • POC glucose
    • CBC
    • Chemistry
    • Coags
    • Troponin
    • T&S
  • ECG
    • In large ICH or stroke, may see deep TWI and prolong QT, occ ST changes
  • Head CT (non-contrast)
    • In ischemia stroke CT has sensitivity 42%, specificity 91%[5]
    • In acute ICH the sensitivity is 95-100%[6]
    • The goal of CTH is to identify stroke mimics (ICH, mass lesions, etc .)[7]
  • Also consider:
    • CTA brain and neck
      • To check for large vessel occlusion for potential thrombectomy
      • Determine if there is carotid stenosis that warrants endarterectomy urgently
    • Pregnancy test
    • CXR (if infection suspected)
    • UA (if infection suspected)
    • Utox (if ingestion suspected)

MR Imaging (for Rule-Out CVA or TIA)

  • MRI Brain with DWI, ADC (without contrast) AND
  • Cervical vascular imaging (ACEP Level B in patients with high short-term risk for stroke):[8]
    • MRA brain (without contrast) AND
    • MRA neck (without contrast)
      • May instead use Carotid CTA or US (Carotid US slightly less sensitive than MRA)[9] (ACEP Level C)

Management

To differentiate between tPA and non-tPA candidates see Thrombolysis in Acute Ischemic Stroke (tPA)

Both tPA AND non-tPA candidates

  • Prevent dehydration
  • Maintain SpO2 > 92%
  • Maintain blood glucose between 140 and 180 mg/dL
  • Prevent fever
  • HOB > 30°

tPA Candidate

Non-tPA Candidate

  • Hypertension
    • Allow permissive hypertension
    • If SBP > 220 or DBP > 120, lower by 25% over 24 hrs (drug of choice is nicardipine)[10]
    • Goal MAP for non-thrombolyzed, MAP < 150, per AHA guidelines[11]
  • 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. [12][13]
  • Anticoagulation not recommended for acute stroke (even for A-fib)

Endovascular Therapy

  • Mechanical clot removal for large vessel occlusions (e.g. M1 occlusion, basilar artery occlusion)
  • Early trials MR RESCUE, SYNTHESIS, and IMSIII showed no benefit and potential harm
  • MR CLEAN Trial show promising outcomes[14]
    • Participants had proximal intracranial artery occlusions
    • Intervention was conducted within 6 hrs
    • Functional independence of 32.6% with endovascular treatment and 19.1% with typical therapy
  • Institutional dependent time window for intervention
  • May require careful patient selection based on last known normal, ICA/prox MCA occlusion, and additional diagnostic studies such as CT perfusion study, Rapid MRI, etc[15]
  • Goal SBP <160 after endovascular therapy [16]

Cerebellar

Corticosteroids

  • Cochrane review showed no benefit in mortality or functional outcomes[17]

Disposition

  • Admit all acute and subacute ischemic strokes

See Also

External Links

References

  1. Macdonell RA, Kalnins RM, Donnan GA. Cerebellar infarction: natural history, prognosis, and pathology. Stroke. 18 (5): 849-55.
  2. Lee H, Kim HA. Nystagmus in SCA territory cerebellar infarction: pattern and a possible mechanism. J Neurol Neurosurg Psychiatry. 2013 Apr;84(4):446-51.
  3. Rezaee A and Jones J et al. Lacunar stroke syndrome. Radiopaedia. http://radiopaedia.org/articles/lacunar-stroke-syndrome.
  4. Internal Capsule Stroke. Stanford Medicine Guide. http://stanfordmedicine25.stanford.edu/the25/ics.html
  5. Mullins ME, Schaefer PW, Sorensen AG, Halpern EF, Ay H, He J, Koroshetz WJ, Gonzalez RG. CT and conventional and diffusion-weighted MR imaging in acute stroke: study in 691 patients at presentation to the emergency department. Radiology. 2002 Aug;224(2):353-60.
  6. Suarez JI, Tarr RW, Selman WR. Aneurysmal subarachnoid hemorrhage. N Engl J Med. 2006; 354(4):387–396.
  7. Douglas VC, Johnston CM, Elkins J, et al. Head computed tomography findings predict short-term stroke risk after transient ischemic attack. Stroke. 2003;34:2894-2899.
  8. ACEP Clinical Policy: Suspected Transient Ischemic Attackfull text
  9. Nederkoorn PJ, Mali WP, Eikelboom BC, et al. Preoperative diagnosis of carotid artery stenosis. Accuracy of noninvasive testing. Stroke. 2002;33:2003-2008.
  10. Zha AM, et al. Recommendations for management of large hemispheric infarction. Curr Opin Crit Care. 2015; 21(2):91-8.
  11. Anton Helman. Emergency Medicine Cases. Episode 17 Part 1: Emergency Stroke Controversies. September 2011. https://emergencymedicinecases.com/episode-17-part-1-emergency-stroke-controversies/
  12. Journal Watch May 17, 2018 Clopidogrel plus Aspirin Has Benefits for TIA or Minor Stroke
  13. Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA N Engl J Med 2018; 379:215-225
  14. Berkhemer OA, et al. A randomized trial of intraarterial treatment for acute ischemic stroke. NEJM. 2015; 372(1):11-20.
  15. 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
  16. Smith M, Reddy U, Robba C, et al. Acute ischaemic stroke: challenges for the intensivist. Intensive Care Med. 2019
  17. Sandercock PA and Soane T. Corticosteroids for acute ischaemic stroke. Cochrane Database Syst Rev. 2011 Sep 7;(9):CD000064.