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