Chapter 230. Cerebral Vascular Accident

A 65-year-old hypertensive black man presented to the emergency department with onset of right face, arm, and hand paralysis, and difficulty communicating. Rapid diagnostic testing using MRI revealed an ischemic infarct in the left middle cerebral artery (Figure 230-1). He was evaluated by a stroke response team and was found to be a candidate for tissue plasminogen activator (TPA). After the stroke, he was treated with aspirin, antihypertensives, and cholesterol-lowering medication. He recovered 80% of his neurologic deficit over the next 3 months. Figure 230-2 is a noncontrast CT image of this patient 2 weeks later.

Cerebral vascular accidents or strokes are common, especially in older populations. Most strokes are ischemic or hemorrhagic. Risk factors include hypertension, smoking, diabetes mellitus, and atrial fibrillation. Thirty-day mortality for a first stroke is greater than 20%.

Stroke.

• Cerebral vascular accidents (CVAs) affect approximately 700,000 people per year in the United States, most being older than age 65 years.1
• Ischemic (66%) and hemorrhagic (10%) strokes account for most strokes.1
• Prevalence of stroke and mortality are higher in blacks than in whites. Prevalence is 753 versus 424 per 100,000 and mortality is 95.8 versus 73.7 per 100,000 for black and white men, respectively.1

• CVAs are typically classified into cardioembolic (15% to 22%), large vessel (10% to 12%), small vessel (15% to 18%), other known cause (2% to 4%), and undetermined cause (46% to 51%).2
• Ischemic CVAs occur when atherosclerosis progresses to a plaque, which ruptures acutely. Each step of this process is mediated by inflammation.3
• Hemorrhagic CVAs occur when vessels bleed into the brain, usually as the result of elevated blood pressure.
• Other known causes of CVAs include inflammatory disorders (giant cell arteritis, systemic lupus erythematosus [SLE], polyarteritis nodosa, granulomatous angiitis, syphilis, and AIDS), fibromuscular dysplasia, drugs (cocaine, amphetamines, and heroin), hematologic disorders (thrombocytopenia, polycythemia, and sickle cell), and hypercoagulable states.

• Hypertension (HTN)—The predominant risk factor for more than 50% of all strokes. Prehypertension (blood pressure in the range of 130 to 139/85 to 89) carries a hazard ratio of 2.5 for women and 1.6 for men.4
• Cigarette smoking carries a hazard ratio of 1.62 for ischemic stroke and 2.56 for hemorrhagic stroke.5
• Type 2 diabetes mellitus (DM) increases the risk of having a stroke six-fold.4
• Black patients at ages 45 and 65 are 2.9 and 1.66 times more likely to have a stroke compared to white patients.6
• Atrial fibrillation increases the risk of stroke. The CHADS2 (congestive heart failure [CHF], HTN, age >75, DM, stroke) scoring system (see below) separates patients into low risk (stroke rate 1% to 1.5% per year), moderate risk (2.5%), high risk (4%), and very high risk (7%).4
• Body mass index (BMI) greater than 30 carries a hazard ratio of 1.45 for ischemic stroke but does not increase the risk of hemorrhagic stroke.5

Diagnosis of CVA must be made expediently to minimize mortality and morbidity.

Clinical Features

• History of risk factors, including older age, HTN, cigarette smoking, type 2 DM, or previous transient ischemic attack (TIA) or stroke.
• Acute onset of neurologic signs and symptoms based on the site of the CVA (see “Typical Distribution” below).

Typical Distribution

TIA or stroke can occur in any area of the brain; common areas with typical symptoms include the following:

• Middle cerebral artery is the most common ischemic site (Figure 230-3):
  • Superior branch occlusion causes contralateral hemiparesis and sensory deficit in face, hand, and arm, and an expressive aphasia if the lesion is in the dominant hemisphere.
  • Inferior branch occlusion causes a homonymous hemianopia, impairment of contralateral graphesthesia and stereognosis, anosognosia and neglect of the contralateral side, and a receptive aphasia if the lesion is in the dominant hemisphere.
• Internal carotid artery (approximately 20% of ischemic strokes) occlusion causes contralateral hemiplegia, hemisensory deficit, and homonymous hemianopia; aphasia is also present with dominant hemisphere involvement.
• Posterior cerebral artery occlusion causes a homonymous hemianopia affecting the contralateral visual field.

Laboratory Testing (Include Ancillary Testing)

These tests may be helpful in the context of an acute stroke, particularly when the cause of the stroke is not immediately evident:

• Complete blood count (CBC) for thrombocytosis or polycythemia.
• Erythrocyte sedimentation rate (ESR) for diseases such as giant cell arteritis or SLE.
• Testing for syphilis using a treponemal enzyme immunoassay (EIA), with positive results confirmed by a nontreponemal test (Venereal Disease Research Laboratory [VDRL]).
• Serum glucose to eliminate hypoglycemia as the cause of the neurologic symptoms.

Imaging

CT or MRI can distinguish ischemic from hemorrhagic and localize the lesion (Figure 230-4).

Other causes of acute neurologic dysfunction include the following:

• TIA—This precursor to a CVA can appear identical; however, no lesion is seen on imaging, and symptoms resolve within 48 hours.
• Multiple sclerosis—Multiple anatomically distinct neurologic signs and symptoms that occur over time and resolve; vision is often affected. MRI findings should help to distinguish multiple sclerosis from CVA.
• Brain mass—More common presentation is headache or seizure; however, may present with focal neurologic signs based on location. CT or MRI will help to diagnose a brain mass and differentiate this from stroke.
• Migraines—Throbbing, unilateral headache with photophobia, and nausea; hemiparesis or aphasia may be part of the aura.
• Vertigo from benign positional vertigo or acute labyrinthitis—Can mimic a CVA in the posterior circulation; however, symptoms such as dysarthria, dysphagia, and diplopia are typically absent.
• Hypoglycemia—Confused state is similar to large stroke syndromes but is easily differentiated by a blood glucose measurement.

Acute Stroke (Within the First 3 Hours)

• Rapidly evaluate or consult specialists to identify candidates for TPA. Odds for a favorable 3-month outcome for TPA compared to no TPA are 2.8 (95% confidence interval [CI], 1.8 to 4.5) for 0 to 90 minutes, 1.6 (95% CI, 1.1 to 2.2) for 91 to 180 minutes.7 SOR A
• Favorable outcomes at 90 days poststroke have also been demonstrated when TPA is given up to 4.5 hours after the onset of symptoms.8 SOR B
• Currently, only 3% of patients who meet the criteria receive TPA.4
• Preliminary studies cautioned about using TPA in community settings; recent studies, however, indicate several options to improve outcomes, including telephone consultation with a regional stroke center.9
• Acutely elevated blood pressure should not be aggressively treated in most cases.

After stabilization, treat ischemic strokes with antithrombotic, antihypertensives, statins, and lifestyle changes.

• Prescribe 81-mg or 325-mg aspirin for secondary stroke prevention in patients with prior ischemic stroke or TIA (relative risk [RR] reduction 28%; number needed to treat [NNT] to prevent 1 stroke per year = 77).4 SOR A
• Lower blood pressure (RR reduction 28%; NNT to prevent 1 stroke per year = 51).4 Current data demonstrate that thiazide-type diuretic and angiotensin-converting enzyme inhibitor (ACEI) (or angiotensin receptor blocker [ARB]) may provide additional risk reduction beyond blood pressure (BP) control and should be used first. ACEI and ARB may not be as effective as monotherapy in black populations.4 SOR A
• Lower low-density lipoprotein (LDL) cholesterol to less than 100 mg/dL for patients with a prior stroke or who are at high risk of stroke using a statin (RR reduction 25%; NNT to prevent 1 stroke per year = 57).4 SOR A
• Assist patients to stop smoking (RR reduction 33%; NNT to prevent 1 stroke per year = 43).4 SOR A
• Advise patients to adopt a healthy lifestyle by eating more fruits and vegetables, losing weight, and maintaining a physical exercise program. SOR B

Consider the following to further decrease morbidity and mortality:

• Avoid indwelling urinary catheters to reduce the risk of urinary tract infection.
• Encourage early ambulation to reduce the risk of a deep venous thrombosis.
• Use antiembolism stockings to reduce the risk of a deep venous thrombosis.
• Consider a swallowing study to identify patients at risk of aspiration.

Special Situations

• Hemorrhagic stroke:
  • Acutely—Do not aggressively lower BP. Some authorities recommend lowering BP only when mean arterial pressure (MAP) is more than 130 mm Hg (MAP = [(2 × diastolic BP) + systolic BP]/3).
  • After the hemorrhagic stroke is over, treat BP aggressively; modest decreases (12/5 mm Hg) from one of many classes of hypertensive drugs lower recurrent stroke risk by 50% to 75%.4
• Nonvalvular atrial fibrillation (AF)—Use the CHADS2 scoring system to identify patients with AF who can be managed with aspirin or should be anticoagulated with coumadin.4
• The CHADS/CHADS2 scoring table is shown below:2
  Table Graphic Jump Location

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  C: Congestive heart failure	= 1 point
  H: HTN (or treated HTN)	= 1 point
  A: Age >75 years	= 1 point
  D: Diabetes	= 1 point
  S: Prior TIA or stroke	= 2 points

  • For 0 to 1 point, use aspirin; 2 points, weigh risk of bleeding, adequacy of follow-up versus benefit; 3 or greater, use warfarin if at all possible.
• Patients with symptomatic carotid stenosis: Refer for carotid endarterectomy patients with 70% to 99% carotid stenosis (without near-occlusion) with ipsilateral focal neurologic signs (absolute risk reduction [ARR] 16.0%).10 Consider referring symptomatic patients with moderate stenosis of 50% to 69% (ARR 4.6%).10 SOR A
• Patients with asymptomatic carotic artery stenosis greater than 60%. Consider referral for carotid endarterectomy in patients younger than the age of 75 years (NNT = 20 to prevent 1 stroke in 5 years).4

• Address modifiable risk factors: Control HTN, high cholesterol and DM; stop smoking; and maintain a healthy body weight.
• The United States Preventive Services Task Force (USPSTF) recommends the use of aspirin for women ages 55 to 79 when the potential benefit of reduction in ischemic strokes outweighs the potential harm of an increase in GI hemorrhage.11
• The USPSTK found the evidence insufficient to recommend for or against the use of aspirin for stroke reduction in men.11

CVA prognosis varies based on size and location of ischemia or hemorrhage, time to TPA administration (for ischemic stroke), and availability of aggressive poststroke rehabilitation.

• The 30-day mortality rate after a first or second stroke is 22% and 41%, respectively.4
• Five-year observed survival is 40% to 68% for stroke.12

• Patients with symptoms of an acute stroke should be hospitalized, evaluated immediately for appropriateness of TPA and treatment of reversible causes, and managed, if possible, in a stroke unit or using the “best practices” associated with these units.
• After a stroke and rehabilitation, patients should be followed at regular intervals to evaluate risk reduction strategies.

Educate patients who have had a stroke about the high risk of having a second stroke, the high morbidity and mortality associated with a recurrent stroke, and the need for lifestyle modifications and medications to reduce this risk.

Patient Resources

• The National Stroke Association has patient information including signs of a stroke and HOPE: The Stroke Recovery Guide—http://www.stroke.org.
• The Internet Stroke Center has a section for patients and families with patient education about signs of a stroke and living after a stroke—http://www.strokecenter.org.
• The National Institute of Neurologic Diseases and Stroke has written and auditory patient information in English and Spanish—http://www.ninds.nih.gov.

Provider Resources

• The Internet Stroke Center has a large collection of stroke scales and clinical assessment tools, a neurology image library, listings of professional resources, and evidence-based diagnosis and management strategies—http://www.strokecenter.org.
• Guidelines for early management of adults with ischemic stroke from the American Heart Association and other partners—http://stroke.ahajournals.org/content/38/5/1655.full.