Stroke (main)

Revision as of 07:07, 28 September 2011 by Jswartz (talk | contribs)

Background

  • Vascular injury that reduces CBF to specific region of brain causing neuro impairment
  • Accurate determination of last known time when pt was at baseline is essential

Anatomy

  1. Anterior Circulation (internal carotid system)
    1. Ophthalmic artery - optic nerve and retina
    1. ACA
      1. Contralateral sensory and motor symptoms in the lower extremity (sparing hands/face)
      2. Left sided lesion: akinetic mutism, transcortical motor aphasia
      3. Right sided lesion: Confusion, motor hemineglect
    2. MCA
      1. Hemiparesis, facial plegia, sensory loss contralateral to affected cortex
      2. Motor deficits found more commonly in face and upper extremity than lower extremity
      3. Dominant hemisphere involved: aphasia
      4. Nondominant hemisphere involved: inattention, neglect, dysarthria without aphasia
      5. Homonymous hemianopsia and gaze preference toward side of infarct may also be seen
  1. Posterior circulation (vertebral system)
    1. Vertebral artery
      1. Crossed neuro deficits (i.e., ipsilateral CN deficits w/ contralateral motor weakness)
      2. Multiple, simultaneous complaints are the rule
        1. Vertigo, headache, nausea, visual disturbances, oculomotor palsies, ataxia
      3. Isolated events are not attributable to vertebral occlusive disease:
        1. E.g. Isolated lightheadedness, vertigo, transient ALOC, drop attacks
    2. Basilar artery
      1. Quadriplegia, coma, locked-in syndrome
    3. Posterior cerebral
      1. Unilateral headache (most common presenting complaint)
      2. Visual field defects (contralateral homonymous hemianopsia, unilateral blindness)
      3. Motor function is typically minimally affected
    4. Posteroinferior cerebellar
      1. Vertigo, gait instability, limb ataxia, HA, dysarthria, N/V, CN abnormalities

Causes

  1. Ischemic (87%)
    1. Thrombotic (80% of ischemic CVA)
      1. Atherosclerosis
      2. Vasculitis
      3. Arterial dissection
      4. Polycythemia
      5. Hypercoagulable state
      6. Infection
    2. Embolic (20% of ischemic CVA)
      1. Valvular vegetations
      2. Mural thrombi
      3. Arterial-arterial emboli from proximal source
      4. Fat emboli
      5. Septic emboli
    3. Hypoperfusion
      1. Cardiac failure resulting in systemic hypotension
  2. Hemorrhagic (13%)
    1. Intracerebral
      1. HTN
      2. Amyloidosis
      3. Anticoagulation
      4. Vascular malformations
      5. Cocaine use
    2. SAH
      1. Berry aneurysm rupture
      2. Vascular malformation rupture

Clinical Features

  • Thrombotic
    • Stuttering or waxing and waning
    • TIA involving same vascular distribution
  • Embolic
    • Sudden onset of symptoms
    • TIAs involving different vascular distributions
    • A-fib
    • Valvular replacement
    • Recent MI
  • Hemorrhagic
    • Sudden onset of symptoms
    • Preceded by severe headache
    • Recent neck trauma/manipulation

DDX

  1. Seizures/postictal paralysis (Todd paralysis)
    1. Transient paralysis following a seizure which typically disappears quickly
    2. Note: seizures can be secondary to a CVA
  2. Syncope
    1. No persistent or associated neurologic symptoms
  3. Brain neoplasm or abscess
    1. Focal neurologic findings, signs of infection, detectable by imaging
  4. Epidural/subdural hematoma
    1. History of trauma, ETOH, anticoagulant use, bleeding disorder; detectable by imaging
  5. Hypoglycemia
    1. Can be detected by bedside glucose measurement, history of DM
  6. Hyponatremia
    1. History of diuretic use, neoplasm, excessive free water intake
  7. Hypertensive encephalopathy
    1. Gradual onset; global cerebral dysfunction, HA, delirium, HTN, cerebral edema
  8. Meningitis/encephalitis
    1. Fever, immunocompromise may be present, meningismus, detectable on LP
  9. Hyperosmotic coma
    1. Extremely high glucose levels, history of DM
  10. Wernicke encephalopathy
    1. History of ETOH or malnutrition; triad of ataxia, ophthalmoplegia, and confusion
  11. Labyrinthitis
    1. Predominantly vestibular symptoms; pt should have no other focal findings
  12. Drug toxicity
    1. Lithium, phenytoin, carbamazepine
  13. Bell's palsy
    1. Neuro deficit confined to isolated peripheral 7th nerve palsy; often a/w younger age
  14. Complicated migraine
    1. History of similar episodes, preceding aura, HA
  15. Meniere disease
    1. History of recurrent episodes dominated by vertigo symptoms, tinnitus, deafness
  16. Demyelinating disease (MS)
    1. Gradual onset, may have hx of multiple episodes of findings in multiple distributions
  17. Conversion disorder
    1. No cranial nerve findings, nonanatomic distribution of findings

Work-Up

  1. Glucose
  2. CBC
  3. Chemistry
  4. Coags
  5. Troponin
  6. Lipid profile
  7. Head CT
  8. ECG
  9. Also consider:
    1. Pregnancy test
    2. Utox
    3. TTE with bubble study


Treatment

Ischemic

  1. Glycemic control
    1. Use insulin to maintain blood sugar < 185
  2. Temperature control
    1. Treat fever > 37.5 (99.5)
  3. If pt is tPA candidate go to --> CVA (tPA Criteria)
    1. Consider tPA
      1. If give tPA DO NOT give antiplatelets/anticoagulants for at least 24 hours
    2. BP Control
      1. If potential candidate for tPA but BP > 185/110:
        1. Labetalol 10-20mg IV over 1-2min, may repeat x 1, OR
        2. Nicardipine IV 5mg/hr, titrate up by 2.5mg/hr q5-15min, max 15mg/hr; when desired BP reached lower to 3mg/hr OR
        3. other agents (hydralazine, enalaprit, etc) may be considered when appropriate
  4. If pt is NOT a tPA candidate:
    1. Aspirin
    2. BP control
      1. Only tx BP if > 220/120
    3. Anticoagulation
      1. Heparin only if cardiac embolic source/ a-fib

Hemorrhagic

See Intracranial Hemorrhage (ICH)

Cerebellar Stroke

  • Can be confused w/ acute vestibular syndrome (e.g. labyrinthitis)
  • HINTS Exam can reliably distinguish the two (more effective than early DWI MRI)
    • Head Impulse Testing
      • Tests vestibulo-ocular reflex
      • Have pt fix their eyes on your nose
      • Move their head in the horizontal plane to the left and right
      • If reflex is intact their eyes will stay fixed on your nose
      • If reflex is abnormal their head will move 1st and then their eyes will "catch up"
      • It is reassuring if the reflex is abnormal (due to dysfunction of the nerve)
    • Nystagmus
      • Benign nystagmus only beats in one direction no matter which direction their eyes look
      • Bad nystagums beats in every direction their eyes look
        • If pt looks left, get left nystagmus, if looks right, get right-beating nystagmus
    • Test of Skew
      • Vertical dysconjugate gaze is bad
      • Alternating cover test
        • Have pt look at your nose w/ their eyes and then cover one eye
          • When rapidly uncover the eye look to see if the eye quickly moves to re-align
    • If any of the above are abnormal obtain full CVA w/u (including MRI)

See Also

Source

  • UpToDate
  • AHA/ASA Acute Stroke Guidelines
  • EMCrit