• Emergency: Very elevated blood pressure with acute, ongoing target-organ damage that should be lowered within minutes.
  
• Urgency: Very elevated blood pressure without acute, ongoing target-organ damage that should be lowered within hours (controversial).

Many patients present to emergency departments or physician offices with very elevated BPs, but few of these involve either hypertensive emergencies or urgencies. True hypertensive emergencies occur in only one to two people per 100,000 population per year in developed countries, but may be up to four times more common in developing nations, minority populations, economically challenged individuals, and those who are nonadherent to prescribed antihypertensive drugs. To triage such patients appropriately it is important to identify symptoms or signs indicating acute, ongoing target-organ damage. This can take several forms, but usually involves the central nervous system (including the optic fundi), cardiovascular system, kidneys, and/or uterus (see the first three columns of Table 45–1). Patients with acute, ongoing target-organ damage are at very high risk of cardiovascular events and generally should be treated within minutes in a heavily monitored setting with a short-acting intravenously delivered antihypertensive agent (typically sodium nitroprusside). Individuals who do not have acute, ongoing target-organ damage may be referred to a source of ongoing care for hypertension (if at low risk), or treated with orally administered antihypertensive agents (if at moderate risk) and the BP response observed.