Hypertensive emergencies

Hypertensive encephalopathy in childhood

Hypertensive encephalopathy is an uncommon but recognized complication of malignant hypertension in children. We reviewed the clinical course, laboratory studies, and outcomes of 12 patients with hypertensive encephalopathy seen at the University of Iowa Hospitals and Clinics between 1979 and 1994. The most common presenting symptoms were seizures, headache, and vision changes. Laboratory studies were nonspecific and in some patients were normal. Hypertensive encephalopathy is a clinical diagnosis. Management consists of recognition of this syndrome and aggressive treatment of hypertension. The neurologic outcome in our series was good.

Advances in pharmacotherapy: treatment of hypertensive crisis

A hypertensive crisis can be caused by many factors. Frequently, the mechanism involved is complex and highly variable among patients. Without drug therapy, this condition is associated with very high mortality and morbidity. There are a number of oral and intravenous hypotensive agents available, which can effectively control blood pressure in a hypertensive crisis. The relative advantages and disadvantages of each treatment option is discussed.

Acute hypotensive action of clonidine after intravenous infusion in hypertensive emergencies

Clonidine was administered by intravenous infusion to 12 patients classified as having exaggerated arterial hypertension, their systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressures were significantly reduced from the third min. The maximal percentage reduction (Mean +/- SEM) reached 30.1 +/- 3.1% (SAP) and 24.7 +/- 2.9% (DAP) after 30 to 110 min of infusion. Initially there were transitory initial increases in SAP (3 patients) and DAP (1 patient). The increases in blood pressure were related to low body surface area (BSA). The dose of clonidine per m2BSA able to reduce by 10% either SAP or DAP (active dose-10), and the dose able to reduce SAP or DAP by 10 mmHg in one minute (systolic or diastolic clonidine unit) were calculated, providing indices for detecting clonidine responsiveness in patients with exaggerated hypertension. This method is advantageous when using clonidine intravenously because it diminishes the risk of overdosage.

Hypertensive emergencies: practical approach to treatment

In a hypertensive crisis, an antihyprtensive agent must be able to reduce blood pressure to safe levels rapidly and predictably. Parenteral therapy is usually necessary, and in general, agents that can be infused and titrated are preferable to those that cannot. This article tells which drugs to use in specific situations and gives explicit instructions for intravenous and oral administration.

Treatment of severe hypertension and hypertensive emergencies with intravenous clonidine hydrochloride

Eleven severely hypertensive patients, median age 54 years, were treated with intravenous (i.v.) clonidine hydrochloride (Catapres). In nine there were life-threatening complications: severe left ventricular failure (LVF), hypertensive encephalopathy, cerebral haemorrhage, dissecting aortic aneurysm, renal failure, and severe epistaxis. In two patients there was pronounced, but uncomplicated, elevation of blood pressure. 0·15 mg or 0·3 mg clonidine was given every 40 min with electrocardiographic (ECG) monitoring. The mean systolic and diastolic blood pressures in the eleven patients were respectively 266 and 165 mmHg before treatment falling to 165 and 109 mmHg after treatment (P < 0·001). The mean decrease in heart rate was 26 beats/min (P < 0·001). Doses of clonidine required for control ranged from 0·15 mg (one ampoule) to 0·9 mg (mean 0·56 mg), although one patient received a total of 0·9 mg without an adequate response. The presenting condition caused the eventual death of two patients. There were no serious side effects, except for one transient episode of sino-atrial heart block. It is concluded that clonidine is effective and safe in the treatment of hypertensive emergencies.