A 57-year-old male with hypertension and end-stage renal disease is brought into the ED by his family for evaluation of headache, nausea, blurry vision, and confusion. Blood pressure is 235/130 mmHg. He is somnolent but arousable and oriented only to person; the remainder of his neurologic exam is nonfocal. A fundoscopic exam shows retinal hemorrhages, exudates, and papilledema. How should this patient be managed?
Hypertension (HTN) is a medical problem that affects an estimated 1 in 3 adults in the U.S. and more than 1 billion people worldwide. The Joint National Committee (JNC) 7 Report defines hypertensive emergency as severe hypertension with evidence of impending or progressive end-organ dysfunction.1 Systolic blood pressure (SBP) in these settings often is >180 mm Hg with diastolic blood pressure (DBP) >120 mm Hg. The JNC 7 Report defines hypertensive urgency as severe HTN without acute end-organ dysfunction. Whereas hypertensive urgencies can be treated with oral antihypertensive agents with close outpatient follow-up, hypertensive emergencies require immediate BP reduction to halt the progression of end-organ damage.
Severe HTN causes shear stress and endothelial injury, leading to activation of the coagulation cascade, fibrinoid necrosis, and tissue ischemia.2 Due to adaptive vascular changes, pre-existing hypertension lowers the probability of a hypertensive emergency developing at a particular BP. The rate of BP rise, rather than the absolute level, determines most end-organ damage.3 In previously normotensive patients, end-organ damage can occur at BPs >160/100 mm Hg; however, organ dysfunction is uncommon in chronically hypertensive individuals, unless BP >220/120 mm Hg.
Clinical manifestations of hypertensive emergency depend on the target organs involved (see Figure 1, right). When a patient presents with severe hypertension, a focused evaluation should attempt to identify the presence of end-organ damage. If present, these patients should be admitted to an ICU for close monitoring, and administration of parenteral antihypertensive agents should be started. (Online Exclusive: View a chart of “Parenteral Antihypertensive Agents Used in Hypertensive Emergencies”)
Review of the Data
General principles: The initial therapeutic goal in most hypertensive emergencies is to reduce the mean arterial pressure (MAP) by no more than 25% within the first hour. Precipitous or excessive decreases in BP might worsen renal, cerebral, or coronary ischemia. Due to pressure natriuresis, patients with primary malignant hypertension might be volume-depleted. Restoration of intravascular volume with intravenous (IV) saline can prevent precipitous falls in BP when antihypertensive agents are started.
After the patient stabilizes, the BP can be lowered about 10% per hour to 160/100-110 mm Hg. A gradual reduction to the patient’s baseline BP is targeted over the ensuing 24 to 48 hours. Once there is stable BP control and end-organ damage has ceased, patients can be transitioned to oral therapy.