Cerebrovascular Accidents or Strokes
Cerebrovascular Accidents or Strokes
Dr. Nusrum Iqbal
Department of Medicine
Lahore Medical & Dental College
Lahore
Definition
Stroke is a clinical condition with all the following features:
An acute neurological disorder
Produced by non-traumatic injury in the central nervous system that is vascular in origin
Accompained by focal rather than global neurologic dysfunction
Persist for longer than 24 hours or results in death within the first 24 hours
Causes
A. Infarction (80-85% cases)
Thrombosis
Embolism
B. Hemorrhage (15-20% cases)
Intracerebral hemorrhage
Sub-arachnoid hemorrhage
Clinical Classification of Stroke
Depending upon the rate of development and reversibility
1. Transient ischemic attack
2. Stroke in evolution
3. Completed stroke
Transient Ischemic Attack
Tranisent neurological deficit due to vascular insufficiency
Completely recovers within 24 hours
Usual duration is few minutes
Due to embolism in most cases
Risk of completed stroke is increased after TIAs
Stroke in evolution
Neurological deficity increases by step vise progression or there is a slow uninterrupted progression
May take 1-2 weeks to complete
Resembles space occupying lesions
Completed stroke
Neurological deficit lasts longer than 24 hours
Pathologic Classification
Ischemic/cerebral infarction
Oclusion of cerebral artery
Thrombosis at the site of atheromatous lesions (commonest)
Embolic - Originates from thrombi in the left atrium (from atral fibrelation) and left ventrical (from acute MI)
Vegetations of endocarditis can also embolize
Cerebral Hemorrhage
50% cases are due to intracerebral hemorrhage
Remaining 50% cases due to subarchnoid hemorrhage
common sites - internal capsule pons, and cerebellum
Causes
Hypertension
Atherosclerosis
AV malformation
Bleeding disorders
Symptoms
Sudden onset of focal neurological symptoms - limb weakness
Fever - 50% cases
Aphasia - infarction or left middle cerebral artery
Headache - raised intracranial pressure
Vomitting - raised intracranial pressure
loss of consciousness - common in intracerebral hemorrhage, massive infarction with cerebral oedema
Fits or seizures - focal seizures are common occurs within 24 hours
Signs
Main Artery Branch Signs
Internal carotid Anterior Hemiplegia and
cerebral hemianesthesia
(legs are involved more than arms and face); incontinence of urine
Signs
Main Artery Branch Signs
Internal carotid Middle Hemiplegia;
cerebral hemianesthesia; dysphasia (if dominant side involved); hemianopia
Signs
Main Artery Branch Signs
Vertebral Posterior Hemianopia,
cerebral cortical blindness; amnesia, thalamic pain.
Signs
Main Artery Banch Signs
Vertebral Basilar/ ataxia;
cerebellar nystagmus; diplopia; dysarthria; dysphagia; facial weakness; hemiplegia/ hemianesthesia on opposite side
Risk factors of stroke
Smoking
Hypertension
Diabetes Mellitus
Ischemic or valvular heart disease
Investigations
Routine Tests
CBC and ESR
Blood glucose Urea creatinine and electrolytes
Lipid profile
ECG
chest x-ray
CT Scan
most useful investigation
infarction, intracerebral hemorrhage and subarchnoid hemorrhage or easily differentiated
Aneurysm and arteriovenous malformations may also be detected (MRI is most sensitive than CT scan)
Diagnostic yield is 50% lower when performed within 24 hours after infarction
MRI
Higher diagnostic yield than CT scans for bland infarctions (cerebellum and brainstem)
reserved for occasional case of suspected stroke in which CT scans are unrevealing
Lumbar puncture/ CSF examination
helpful if signs of meningeal irritation are present
subarchnoid hemorrhage
Not indicated in most cases
equivocal evidence of subarchnoid hemorrhage on CT scan
Echo cardiography
indicated when stroke is associated with atrial fibrilation acute MI or left sided endocarditis
Angiography - aneurysms and AV malformation
EEG - f seizures are suspected as the cause of the neurologic deficit
Management
Immediate Management
Admission to hospital
Secure airways, breathing and circulation
Monitor vital signs
Management of hypertension, antihypertensive treatment is indicated when the cystolic blood pressure is above 220 mmHg or when mean blood pressure is above 130 mm.
Nicardipine a calcium channel blocker that preserves cerebral blood flow
Ace inhibitors
Nitroglycerine and nitroprusside should be avoided (cerebral vesodilator)
Anti coagulations
Heparin
progressive ischemic stroke
recent studies reveals little or no benefit from full anticoagulation in progressive ischemic stroke
Thrombolytic therapy
It should be used in the first three hours after the onset of acute ischemic stroke
TPA (tissue palasminogen activator)
Proper protocol should be followed as described by National Institute of Neurologic Disorders and Stroke
Increase intracranial Pressure
Elevating the head of the bed to 30 degree (promote venous return from the head)
endotracheal suctioning should be reduced in frequency and duration if possible
High dose steroids should be avoided in all cases of intracranial hypertension and can increase the risk of infection
Mannitol lowers intracranial pressure by growing water out of cerebral tissue
Hyperventilation to induce hypocapnia and reduce cerebral blood flow does not improve outcome
Long term Management
Medical therapy
all risk factors should be identified and if possible, treated
Antihypertensive therapy
Antiplatelet therapy, soluble aspirin
Anticoagulants (heparin and warfarin)
polycythemia should be treated if found
baclofan (GABA agonist) is helpful in the management of severe spasticity
Surgical Approaches
Internal carotid endarterectomy
patients who are shown to have internal carotid artery stenosis that narrows arterial lumen by more than 70%
risk of further TIA/stroke is reduced by approximately 75% following successful surgery
procedure has a mortality around 3%
Extracranial-intracranial bypass
there was no overall benefit, procedure is now largely obsolete
Rehabilitation
Physiotherapy and Speech Therapy
Helpful in relieving spasticity preventing contratures and teaching stroke patients to use walking ads
Speech therapy is recommended following aphasia
both physiotherapy and speech therapy have an undoubted psychological notes
modifications may be necessary at home e.g. stair rails, portable lavatory, bath rails, sliding boards, wheel chairs, tripods, modification of doorways and sleep arrangements
Laison between hospital occupational therapist and primary care physician is valuable
Management of Hemorrhagic Stroke
General management is that of ischemic stroke
urgent neuro-surgical evacuation of the clot if it is expanding
hypertension should be controlled properly
dexamethasone is often prescribe to reduce cerebral oedema
nimodipine a calcium channel antagonist has been shown to reduce mortality
Subarachnoid hemorrhage (SAH)
Is usually the result of aneurysmal rupture or bleeding from an arteriovenous malformation
SAH can differ from the other types of stroke in both presentation and management
Clinical Presentation
Hallmark of the clinical presentation of SAH in headache
headache of SAH is usually abrupt in onset, persistent, progressive and worse with exertion
headache of SAH tends to be centered at the base of the skull in the cervical region
nausea, vomiting, mental status changes, stiff neck
Diagnostic Evaluation
CT scans of the head (unenhanced) have a 90% sensitivity
initial diagnostic test of choice for suspected SAH
CT scans can miss SAH in the posterior fossa
a negative CT scan does not eliminate the possibility for SAH
Management
Cerebral angiography is performed to identify the responsible vascular abnormality for surgical correction
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