RHS 332: Clinical Neurology

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RHS 332 Clinical Neurology

• Ahmad Alghadir, M.S. Ph.D. P.T.
• Room 2071
• aalghadir_at_hotmail.com
• alghadir_at_ksu.edu.sa

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Recommended texts

• S.B. Osullivan, T.J. Schmitz, Physical
  Rehabilitation Assessment and Treatment, F.A.
  Davis Company. 3rd ed. 1994.
• R.L. Braddom, Physical Medicine Rehabilitation,
  W.B. Saunders Company. 1st ed. 1996.

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Stroke
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Introduction

• Cerebrovascular accident (CVA) sudden, focal
  neurologic deficit resulting from ischemic or
  hemorrhagic lesions in the brain.
• Deficits sensory, motor (hemiplegia or
  hemiparesis), functional, coordination, mental,
  and language impairments.

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• The location and extent of the lesion and the
  amount of collateral blood flow determine the
  severity of neurologic deficits.

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Epidemiology (US)

• The most common cause of adult disability.
• 500,000 new victims each year.
• 30 die during the acute phase.
• Of the survivors, 35 have severe disability.
• 20 of strokes occur in persons under the age of
  65.

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• Males have a 30 greater incidence of stroke than
  females.

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Etiology

• Cerebral thrombosis (blood clot) ? occlusion ?
  ischemia ? infarction.
• Cerebral embolism (foreign body) ? occlusion ?
  ischemia ? infarction.
• Hemorrhage ? ischemia and mechanical injury ?
  infarction.

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Risk factors

• Hypertension ? rupture ? hemorrhage.
• Atherosclerosis ? slow blood stream ? thrombosis
  ? occlusion ? ischemia ? atherothrombotic brain
  infarction (ABI, 57).
• Atherosclerosis ? stenosis ? hypertension ?
  rupture ? hemorrhage.
• Atherosclerosis ? weakness ? rupture ?
  hemorrhage.

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• Elevated blood cholesterol and lipids.
• Excessive alcohol consumption.
• Transient ischemic attacks.
• Physical inactivity.
• Heart diseases.
• Prior stroke.
• Diabetes.
• Smoking.
• Obesity.

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Pathophysiology

• Core (focal infarction) ? irreversible neuronal
  death.
• Penumbra (surrounding ischemic area)? reversible
  metabolic changes.

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• Cerebral edema begins within hours of the insult
  ? reaches a maximum by about 4 days ? subsides
  gradually ? disappears by 3 weeks.
• Cerebral edema ? elevation of intracranial
  pressure ? caudal shift of brain ? death (most
  common cause of death in acute stroke).

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• Symptoms of stroke result from a restriction of
  cerebral blood flow (CBF) greater than 80.

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• Factors influencing symptoms of stroke include
• The location of the ischemic process.
• The size of the ischemic area.
• The nature and functions of the structures
  involved.
• The availability of collateral blood flow
  (rapidity of the occlusion).

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CBF

• CCA ? ICA ? ACA ? medial aspect of frontal and
  parietal lobes.
• CCA ? ICA ? MCA ? lateral aspect of frontal,
  parietal, temporal, and occipital lobes.
• SA ? VA ? BA ? PCA ? medial aspect of temporal
  and occipital lobes.

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Autoregulatory mechanisms

• Modulate a constant rate of CBF through the brain
  (50-60 ml / 100 g of brain tissue / m) (17 of
  cardiac output).
• Blood concentration of O2 and CO2 increase in
  CO2 or decrease in O2 ? vasodilation ? increase
  CBF / decrease in CO2 or increase in O2 ?
  vasoconstriction ? decrease CBF.

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• Blood pH fall in pH (increased acidity) ?
  vasodilation ? increase CBF / rise in pH
  (increased alkalinity) ? vasoconstriction ?
  decrease CBF.
• Blood pressure fall in pressure ? vasodilation ?
  increase CBF / rise in pressure ?
  vasoconstriction ? decrease CBF.

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• Blood viscosity increase in viscosity ?
  vasodilation ? increase CBF / decrease in
  viscosity ? vasoconstriction ? decrease CBF.
• Local function of brain tissue increase in
  function ? vasodilation ? increase CBF / decrease
  in function ? vasoconstriction ? decrease CBF.

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Vascular syndromes

• ACA stroke
• Occlusion proximal to anterior communicating
  artery ? minimal deficits.
• Occlusion distal to anterior communicating artery
  ?
• Contralateral hemiparesis and cortical sensory
  loss with greater involvement of the lower
  extremity than upper extremity.

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• Memory and behavioral impairments.
• Unilateral neglect.
• Incontinence.
• Apraxia inability to perform purposeful
  movements (corpus callosum).
• Agraphia loss of the ability to write (corpus
  callosum).

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• MCA stroke
• Contralateral hemiparesis or hemiplegia and
  sensory deficit of the face, arm, and leg, with
  the face and arm more involved than the leg.
• Loss of conjugate gaze to the opposite side.
• Contralateral homonymous hemianopsia.

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• Unilateral neglect.
• Aphasia.

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• PCA stroke
• Visual agnosia inability to recognize familiar
  objects visually.
• Prosopagnosia inability to recognize faces.
• Contralateral homonymous hemianopsia.
• Cortical blindness (bilateral infarction).
• Loss of memory.

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• Hemianesthesia contralateral sensory loss
  (thalamus).
• Thalamic sensory syndrome contralateral
  unpleasant hemibody sensation (thalamus).
• Resting tremor (basal ganglia).
• Athetosis (basal ganglia).
• Hemiballismus (subthalamic nucleus).
• Contralateral hemiplegia (cerebral peduncle).

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• ICA stroke
• Complete occlusion ? massive infarction ? coma ?
  death.
• Incomplete occlusion ? mixture of ACA and MCA
  stroke.

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• VBA stroke
• Complete occlusion ? progressive occipital
  headache ? coma ? death.
• Incomplete occlusion ? all of the above
  cerebellar symptoms cranial nerve
  abnormalities.