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INTRODUCTION AND EPIDEMIOLOGY
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Hypertension affects approximately 30% of the U.S. population, and 1% to 6% of all ED patients will present with severe hypertension.1,2,3,4,5 Of the latter, between a third and one half will have end-organ damage.2,3,4,5 Risk factors for the development of hypertensive crisis include obesity, cigarette smoking, and older age.6
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Chronic hypertension is categorized into three classifications: prehypertension, stage 1 hypertension, and stage 2 hypertension7 (Table 57-1).
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Hypertensive emergency is an acute elevation of blood pressure (≥180/120 mm Hg) associated with end-organ damage; the targeted end organs include the brain, heart, aorta, kidneys, or eyes7 (Table 57-2). Acute hypertensive emergencies are more common in chronic hypertensive patients who fail to adhere to their antihypertensive therapy regimens and those who are unable to access outpatient health care.6
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