Hypertensive crisis affects upward of 500,000 Americans each year. Although the incidence of hypertensive crisis is low, affecting fewer than 1% of hypertensive adults, more than 50 million adult Americans suffer from hypertension. Presentation of a patient with severe hypertension to the emergency room demands immediate evaluation, prompt recognition of a hypertensive emergency or urgency, and the prompt institution of appropriate therapeutic measures to prevent progression of target-organ damage and to avoid a catastrophic event. Hypertensive emergencies are severe elevations in blood pressure that are complicated by evidence of progressive target-organ dysfunction such as coronary ischemia, disordered cerebral function, a cerebrovascular event, pulmonary edema, or renal failure. Although therapy with parenteral antihypertensive agents may be initiated in the emergency department, these patients warrant prompt admission to an intensive care unit where continuous monitoring of blood pressure can be assured during therapy.
Hypertensive urgencies are severe elevations in blood pressure without evidence of progressive target organ dysfunction and can usually be managed by orally administered medications initiated in the emergency department with appropriate follow-up within 24 hours, to several days depending upon individual characteristics of the patient. Elevated blood pressure alone rarely requires emergency therapy.1
Most hypertensive urgencies or emergencies are preventable and are the result of inadequate treatment of mild to moderate hypertension or nonadherence to antihypertensive therapy.2,3 In a few cases, a previously unrecognized form of secondary hypertension, such as renal vascular hypertension or pheochromocytoma, and rarely, primary hyperaldosteronism, may be responsible and will obviously require early recognition if specific therapy is to be initiated. Prompt emergency room evaluation is undertaken to identify the clinical status of the patient, to provide clues to an underlying etiology of the hypertension, to assess the degree of target organ involvement, and to select the most appropriate pharmacologic agent and method of administration.