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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