title: Hypertensive emergencies.
abstract: A hypertensive emergency is a situation in which uncontrolled hypertension is associated with acute end-organ damage. Most patients presenting with hypertensive emergency have chronic hypertension, although the disorder can present in previously normotensive individuals, particularly when associated with pre-eclampsia or acute glomerulonephritis. The pathophysiological mechanisms causing acute hypertensive endothelial failure are complex and incompletely understood but probably involve disturbances of the renin-angiotensin-aldosterone system, loss of endogenous vasodilator mechanisms, upregulation of proinflammatory mediators including vascular cell adhesion molecules, and release of local vasoconstrictors such as endothelin 1. Magnetic resonance imaging has demonstrated a characteristic hypertensive posterior leucoencephalopathy syndrome predominantly causing oedema of the white matter of the parietal and occipital lobes; this syndrome is potentially reversible with appropriate prompt treatment. Generally, the therapeutic approach is dictated by the particular presentation and end-organ complications. Parenteral therapy is generally preferred, and strategies include use of sodium nitroprusside, beta-blockers, labetelol, or calcium-channel antagonists, magnesium for pre-eclampsia and eclampsia; and short-term parenteral anticonvulsants for seizures associated with encephalopathy. Novel therapies include the peripheral dopamine-receptor agonist, fenoldapam, and may include endothelin-1 antagonists.
authors.affiliation: Department of Medicine, Weill Medical College of Cornell University, New York Presbyterian Hospital, NY, USA.
authors.forename: C J
authors.initials: CJ
authors.lastname: Vaughan
authors.forename: N
authors.initials: N
authors.lastname: Delanty
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology; D020343:Hypertensive Encephalopathy / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology
chemical_list: D000959:Antihypertensive Agents