Treating hypertensive emergencies

Diastolic blood pressure of 120 mm Hg or more is often cited as identifying a hypertensive crisis. However, the absolute level of blood pressure may not be as important as the rate of increase. One important feature that distinguishes hypertensive emergency from hypertensive "urgency" is the ongoing vascular damage that occurs with hypertensive emergency. When this is present, therapy should be initiated as soon as possible. The initial goal is to reduce mean arterial pressure about 15% to 25% within the first 48 hours. Overzealous or uncontrolled reduction in blood pressure may result in coma, stroke, myocardial infarction, acute renal failure, or death. Thus, a drug with titratable dosing (eg, intravenous nitroprusside sodium [Nipride, Nitropress]) is preferred in most situations. Patients with hypertensive urgency do not have evidence of vascular damage. Usually, they are asymptomatic, have no retinal lesions, and have a marked elevation in diastolic blood pressure. Hypertensive urgency does not require immediate normalization of blood pressure, but initiation of therapy and careful follow-up are critical.