Stroke

Overview

Definition

A stroke occurs when there is a disruption of the cerebral blood flow to the brain, resulting in temporary or permanent neurologic deficits. There are two broad categories of stroke. Ischemic stroke (cerebral infarction) accounts for 80% of all strokes and results from embolic obstruction or from thrombosis. Hemorrhagic stroke, the other 20% of strokes, results from bleeding either into the subarachnoid space or the parenchyma of the brain. In the United States, approximately 550,000 individuals suffer a stroke annually. Half of these people are left disabled and endure years of rehabilitation.

Etiology

Ischemic:

Thrombotic:

• Ulcerated atherosclerotic plaque site develops a blood clot in a area of turbulent blood flow and occludes an artery
• Protein C or S deficiency
• Sickle cell anemia
• Polycythemia vera
• Drug abuse

Embolic:

• Mitral stenosis produces thrombi, causing large cerebral emboli
• Valvular heart disease
• Bacterial endocarditis
• Atrial fibrillation
• Myocardial infarction (MI)
• Artery-to-artery embolus

• Lacunar—diabetes, hypertension; atherosclerosis of small arteries
• Cerebral atherothromboembolism of unknown source—hypercoaglability factors

Hemorrhagic:

• Intracerebral—bleeding directly into brain matter, usually at bifurcations of major arteries at base of brain
• Subarachnoid—bleeding outside brain parenchyma into cerebrospinal fluids (CSF) generally either from arteriovenous malformations or cerebral aneurysms; three-fourths occur at the circle of Willis
• Small arteries, damaged by age and hypertension, rupture

Risk Factors

• TIAs, history of stroke
• Aging
• Men > women
• Hypertension
• Heart disease
• Traumatic injury
• Substance abuse (cocaine, alcohol)
• Total serum cholesterol—for older patients
• Diabetes
• Increased blood viscosity
• African or Japanese Americans
• Use of oral contraceptives
• Smoking

Signs and Symptoms

Vary depending on location

• Ischemic stroke—sudden or insidious onset of focal deficits; paresthesias; hemiparesis; hemianopia; hemisensory deficits; swallowing difficulties; aphasia; pallor; pain
• Hemorrhagic stroke—altered mental status may deteriorate rapidly to coma; focal neurologic deficits; vomiting; headache (excruciating if subarachnoid); dysphagia; hemiparesis
• Transient ischemic attacks (TIAs)—resolve within 24 hours (usually 5 to 20 minutes); 50% of patients will have a stroke within five years

Differential Diagnosis

• Brain tumor
• Hematoma—subdural or epidural
• Brain abscess
• Migraine
• Hypoglycemia
• Meningitis
• Encephalitis
• Glaucoma
• Dementia
• Labyrinthitis

Diagnosis

Physical Examination

Pallor and altered mental status may be apparent. Patient may complain of pain and/or numbness.

Laboratory Tests

Complete blood count:

• Platelet count—identifies thrombocytosis, thrombocytopenia
• Coagulation study
• Blood viscosity
• Cardiac isoenzymes

Erythrocyte sedimentation rate:

• Urinalysis
• Drug screening

Pathological Findings

• Cerebral blood flow (CBF) below 15 to 18 ml/100 g of brain/min—areas where brain loses electrical activity evidence neurologic deficit
• CBF below 10 ml/100 g of brain/min—membrane integrity and function failure occurs; anoxia leads to cerebral infarction
• Free radical formation, glutamate release, and increased extracellular potassium and intracellular calcium potentiate neuronal death
• Total depletion of adenosine triphosphate (ATP) within five minutes, causing lactate and glucose levels to rise excessively

Imaging

• Computerized tomography (CT)—distinguishes ischemic (takes 6+ hours) from hemorrhagic (reliable diagnosis 95%) stroke; differential diagnoses
• Magnetic resonance imaging—less accurate distinguishing ischemic from hemorrhagic stroke than CT; identifies acute posterior stroke, vascular malformations, tumor
• Angiogram—accurately measures degree of stenosis; identifies location of hemorrhages, aneurysms

Other Diagnostic Procedures

• Check temperature, breathing, airway passage clearance
• Neurologic examination
• Funduscopic evaluation
• Motor/sensory evaluation
• Cerebral evaluation—assessment of reflexes and gait
• Electrocardiogram (EKG)—reveals atrial fibrillation, MI
• Echocardiogram—identifies thrombus, tumor
• Lumbar puncture—diagnoses hemorrhagic stroke when blood is found in the CSF

Treatment Options

Treatment Strategy

Effective management now focuses on emergent treatment targeted for the specific location and type of injury that has occurred with the goal of preventing neurologic deficits from becoming irreversible. The therapeutic window is estimated at two to six hours. Intervention and support, psychotherapy, and drug treatments may be employed. General strategies include the following.

• Control glucose level
• Administer oxygen
• Maintain airway—possible intubation
• Maintain cerebral perfusion
• Elevate head—promotes venous drainage
• Hyperventilation—decreases intracranial pressure
• Control overhydration—prevents cerebral edema
• Control dehydration—prevents further ischemia; isotonic saline—can cause cardiac or renal disease
• Lumbar puncture—for subarachnoid hemorrhage

Drug Therapies

• Treat only severe hypertension (e.g., carefully titrated nitroprusside or angiotensin-converting enzyme)—prevents irreversible damage to the penumbra, recurrent bleeding
• Thrombolytic therapy—aids vasoconstriction and platelet aggregation; prevents MI, deep venous thrombosis, pulmonary embolism; recombinant tissue plasminogen activator (rt-PA) 1.1 mg/kg to 100 mg maximum, 10% bolus, remainder infused over 1 hour; side effect—intracerebellar bleeding; contraindicated in hemorrhagic stroke
• Diuretics—reduce cerebral edema; possible rebound swelling
• Calcium-channel blockers—prevent vasospasm with subarachnoid hemorrhage; nimodipine 60 mg every 6 hours
• Anticoagulants (e.g., heparin 3,000 to 5,000 units intravenously) reduces stenosis, cardioembolic stroke recurrence, stroke from nonvalvular atrial fibrillation; contraindicated in hemorrhagic stroke
• Antiplatelets—commonly used for strokes of undetermined origin; aspirin 300 mg/day

Surgical Procedures

• Especially for brain stem compression, ventricular obstruction
• Prophylactically for subarachnoid hemorrhage (prevents infarction, further ischemia)
• Cartoid endarterectomy (removes stenotic plaques)

Complementary and Alternative Therapies

CAM for strokes includes prevention and treatment of risk factors (hypertension, diabetes, and cardiovascular disease) and preventing recurrences. Regular exercise and/or physical therapy is very important. Diet and nutrition play an important role. Homeopathy can sometimes provide dramatic relief. Gingko is an important part of any treatment. Other herbs may be useful.

Nutrition

• Diet: high fiber, low saturated fat, low sodium, high potassium, high magnesium foods
• Alcohol increases risk of hemorrhagic stroke, probably due to its effect on platelet aggregation.
• Garlic and onion help regulate lipids and atherosclerosis.
• Folate: deficiencies associated with hyperhomocystinemia and cardiovascular disease (400 to 800 IU/day)
• Essential fatty acids: regulate platelet aggregation and arachidonic acid metabolites. Reduce animal fats and increase fish. A mix of omega-6 (evening primrose) and omega-3 (flaxseed) may be optimal (2 tablespoons oil/day or 1,000 to 1,500 IU bid).
• Vitamin E: 400 to 1,600 IU/day, may protect against cerebral thrombosis, antioxidant
• Coenzyme Q10: 10 to 50 mg/day, increases oxygenation of heart and other tissues
• Vitamin C: 1,000 mg tid: antioxidant to prevent progressive tissue damage
• Bromelain: 250 mg tid between meals, decreases inflammation at the vascular level, which may be a precipitating factor in stroke and recurrences

Herbs

Herbs may be used as dried extracts (pills, capsules, or tablets), teas, or tinctures (alcohol extraction, unless otherwise noted). Dose for teas is 1 heaping tsp. herb/cup water steeped for 10 minutes (roots need 20 minutes).

• Gingko biloba may be used specifically for depression and/or dementia post-stroke due to decreased blood flow (60 to 80 mg tid), also used for arterial occlusive disease. Use carefully with hemorrhagic stroke.
• Hawthorn (Crataegus species) used in mild cardiac insufficiency, with historic use as a heart and vascular tonic and to strengthen connective tissue
• Mistletoe (Viscum album) to treat and prevent atherosclerosis

Homeopathy

An experienced homeopath would consider an individual's constitutional type to prescribe a more specific remedy and potency. Some of the most common acute remedies are listed below. Acute dose is three to five pellets of 12X to 30C every one to four hours until symptoms resolve.

• Acontitum napellus for numbness and/or paralysis after a cerebral accident that is associated with a great anxiety
• Belladonna for stroke that leaves person very sensitive to any motion, with vertigo and trembling
• Kali bromatum for stroke resulting in restlessness, wringing of the hands or other repeated gestures, insomnia, and night terrors
• Nux vomica for cerebral accident with paresis, expressive aphasia, convulsions, and great irritability

Acupuncture

Anecdotal, but worth considering for rehabilitation. Scalp acupuncture, in particular, may be helpful during rehabilitation process.

Patient Monitoring

Patients should be hospitalized with stroke, then monitored carefully at residential rehabilitation facility or home for potential recurrence. Physical therapy and/or speech therapy may help patients relearn and improve motor skills and speech.

Other Considerations

Prevention

• Aspirin—reduces recurrence; 300 mg/day
• Prevention of known risks (e.g., anticoagulants for atrial fibrillation, controlling diabetes) significantly prevents stroke

Complications/Sequelae

• Seizure
• Depression—up to 50% of patients
• Deep venous thrombosis
• Urinary tract infection
• Pneumonia
• Cytotoxic edema
• Vasospasm
• Pulmonary emboli
• Dementia—about 20% of patients

Prognosis

• Overall mortality—30%; hemorrhage mortality—35% to 50% at 30 days
• 90% of deaths occur in the first week

Rehabilitation is often long, involving physical and occupational therapies:

• 80% ambulatory
• 60% achieve self-care
• 25% permanent moderate to severe deficits

Pregnancy

The use of oral contraceptives and pregnancy both increase the risk of stroke.

References

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