Management of patient with Cerebrovascular Disorders
An “umbrella term” refers to a functional abnormality of the central nervous system that occurs when the normal blood supply to the brain is disrupted.
CVA Cerebrovascular disorders
Is the primary cerebrovascular disorders in the united states and in the world.
2 types of strokes
Ischemic –vascular occlusion and significant hypo-perfusion occur.
Hemorrhagic –extravasations of blood into the brain and subarachnoid space.
An ischemic stroke, cerebrovascular accident (CVA), or “brain attack” is a sudden loss of function resulting from disruption of the blood supply toa part of the brain.
Ischemic strokes are subdivided into five
Large artery thrombotic strokes- cause by atherosclerotic plaques in the large blood vessels of the brain.
Small penetrating artery thrombotic strokes- also called lacunar strokes because of the cavity that is created after the death of the infracted brain tissue.
Cardiogenic embolic strokes- associated with cardiac dysrythmias, usually atrial fibriliation. Also associated with valvular heart disease and thomboli in the left ventricle. Emboli originates from the heart and circulate to the cerebral vasculature, most commonly the left middle cerebral artery, resulting a stroke.
Cryptogenic strokes- no know cause and strokes from other cause, such as illicit drug use,coagulopathies,migraine, and spontaneous dissection of the carotid or vertebral arteries.
Hemorrhagic strokes are caused by arteriovenous malformations (AVM’s), aneurysm ruptures, certain drugs, uncontrolled hypertension, hemangioblastomas, and trauma. These strokes can occur in epidural, subarachnoid, or intracerebral hemorrhage.
Ischemic strokes can be caused by cardiovascular disease (cerebral embolism may originate in the heart) and dysrhytmia (atrial fibrillation); risk factors for coronary artery disease apply to stroke as well. Ischemic stroke can also be caused by vasospasm, migraines, and coagulopathies (eg, high hematocrit).
General cerebral ischemia may be caused by excessive or prolonged drop in blood pressure.
Drug abuse (cocaine) can cause stroke , particularly in adolescents and young adults.
Alcohol consumption may also be a risk factor
Pathopysiology Energy failure ION IMBALANCE ACIDOSIS GLUTAMATE DEPOLARIZATION INTRACELLULAR CALCIUM INCREASED CELL MEMBRANES AND PROTEINS BREAKDOWN FORMATION OF FREE RADICALS PROTEIN PRODUCTION DECREASED CELL INJURY AND DEATH ISCHEMIA
Numbness or weakness of face, arm or leg
Sudden severe headache
Confusion or change in mental status
Trouble speaking or understanding speech
Difficulty walking, dizziness, or loss of balance or coordination
Hemiplegia – paralysis of one side of the body
Hemiparesis – weakness of one side of the body
Dysarthria – difficulty in speaking
Dysphasia or Aphasia – impaired speech or loss of speech
Apraxia – inability to perform a previously learned action
Homonymous hemianopsia – loss of the half of visual field
Disturbances in visual -spatial relations – perceiving the relationship of two or more objects in spatial area
Loss of proprioception –inability to perceive the position and motion of body parts
Agnosia – deficits in ability to recognize previously familiar objects
Cognitive Impairment and Psychological Effect
Frontal lobe damage; learning capacity, memory or other higher cortical intellectual functions may be impaired.
Depression, other psychological problems: emotional lability, frustration , hostility , resentment , and lack of cooperation
Transient urinary incontinence
Persistent urinary incontinence or urinary retention ( may be symptomatic of bilateral brain damage )
Continuing bladder and bowel incontinence ( may reflect extensive neurologic damage )
Assessment and Diagnostic Methods
History and complete physical and neurologic examination
Noncontrast computed tomography (CT) or magnetic resonance imaging (MRI) scan, transthoracic or transesophageal echocardiogram
Transcranial Doppler flow studies
Warfarin Sodium ( Coumadin ) for those with atrial fibrillation ( or cardioembolic stroke ).
Platelet inhibiting medications , including aspirin, extended-release dipyridamole (Persantine) plus aspirin, clopidogrel (Plavix), and ticlopidine (Ticlid), decrease the incidence of cerebral infarction.
3-hydroxy-2-methyl-glutaryl-coenzyme A reductase inhibitors (statins) to reduce coronary events and strokes.
Thrombolytic agents or t-PA, used to threat ischemic stroke by dissolving the blood clot that is blocking the blood flow to the brain .
Therapy for patients with Ischemic Stroke Not Receiving t-PA
IV Heparin or low molecular weight heparin.
Surgical Prevention of Ischemic Stroke
Carotid endarterectomy is the removal of an atherosclerotic plaque or thrombus from carotid artery.
For complications of carotid endarterectomy are stroke, cranial nerve injuries, infection or hematoma, carotid artery disruption.
It is important to:
Maintain adequate blood pressure level in the immediate post operative period , avoid hypotension to prevent cerebral ischemia and thrombosis.
Close cardiac monitoring is necessary, because patient have a high incidence of coronary artery disease.
After carotid endarterectomy monitor and document assessment parameters for all body systems with particular attention to neurologic status.
Formation of thrombus at the site of endarterectomy when there is increase in neurologic deficits. The patient should be prepared for repeat endarterectomy.
Assessment of the following: cranial nerves; facial (VII), vagus (X), accessory (XI) and
Edema on neck after surgery is expected, however extensive edema and hematoma formation can obstruct the airway supplies, including those needed for tracheostomy, must be available
Other Complications include
Hyperperfusion Syndrome , occurs when cerebral vessel autoregulation fails. Observe for severe unilateral headache improved by sitting upright or standing.
Intracerebral hemorrhage , occurs infrequently, but is often fatal and results in serious neurologic impairment.
An increase in cerebral edema – the consequences may be deadly if not treated early – is indicated by any change or decrease in the level of consciousness, a rapid increase in the systolic blood pressure with no change in the diastolic – called a widened pulse pressure, bradycardia, & a change from a slow to rapid irregular breathing pattern.
Accounts for 15 % of cerebrovascular disorder and are primarily caused by an intracranial or subarachnoid hemorrhage.
Patients generally have more severe deficits and a longer recovery time compared to those with ischemic stroke.
Caused by bleeding into the brain tissue, the ventricles, or the subarachnoid space
Primary cerebral hemorrhage from a spontaneous rupture of small vessels accounts for approximately 80% or hemorrhagic strokes and its primarily caused by uncontrolled hypertension
Secondary intracerebral hemorrhage is associated with arteriovenous malformations (AVM), intracranial aneurysms, or certain medications
Also known as bleeding into the brain substance
Most common in pt. with HPN and cerebral atherosclerosis because degenerative changes from disease cause rupture of the vessels.
They also may be due to certain types of arterial pathology, brain tumor, and use of medications ( oral anticoagulants, amphetamines, and illicit drugs such as crack and cocaine).
The bleeding is usually arterial and occurs most commonly in the cerebral lobes, basal ganglia, thalamus, brain stem (mostly the pons), and cerebellum.
The bleeding ruptured the wall of the lateral ventricles and causes intraventricular hemorrhages which is frequently fatal.
B.Intracranial ( cerebral) aneurysms
Aneurysm is the dilatation of the walls of a cerebral artery that develops as a result of weakness in the arterial wall.
A cause of aneurysm is unknown.
May be due to atherosclerosis, resulting in the defect in the vessel wall with subsequent weakness of the wall, congenital defect of the vessel wall, hypertensive vascular disease and head trauma.
Artery in the brain can be the site of cerebral aneurysm.
The cerebral arteries most affected by an aneurysm are the internal carotid artery (ICA), anterior cerebral artery (ACA), ante communicating artery (ACoA), posterior communicating artery (PCoa), posterior cerebral artery (PCA), and middle cerebral artery (MCA)
C. Arteriovenous Malformations
AVM is due to an abnormality in embryonal development that leads to a tangle of arteries and veins in the brain without a capillary bed. And leads to dilatation of the arteries and veins and rupture.
Common cause of hemorrhagic stroke in young people.
D. Subarachnoid Hemorrhage
May occur as a result of an AVM, intracranial aneurysm, trauma or HPN .
The most common cause is a leaking aneurysm in the circle of willis or a congenital AVM or the brain.
This is a picture of a bleeding aneurysm that has led to a subarachnoid hemorrhage.