Systemic Hypertension
Three categories of ED presentations (Annals 41:1, April 2003; excellent review article):
- Severely Increased BP: no treatment, f/u within a week
- Hypertensive Urgency: Increased BP (DBP >115 to 120 mm Hg) with evidence of prior, but not active end organ damage. Examples are a patient with a history of MI or CVA
- Hypertensive Emergency: Increased BP with signs of acute end organ damage
Clinical Examination
Take BP in both arms, and before and after evaluation to get true reading
Examine fundi for retinal hemorrhage and papilledema
Signs of Heart Failure
Creatinine and UA for protein and blood. Urine dipstick totally normal rules out clinically significant creatnine elevation (AEM 2002 9:1) Signs of acute damage are large numbers of red cells and red cell casts
EKG
Drugs for HTN Emergency
nitroprusside is the traditional first choice (beware in renal failure), but labetalol is quickly becoming a more attractive option. Aim to reduce MAP by 30-40% over the first two hours.
Drug Dose* Onset of Action Duration of Action Adverse Effects Special Indications Vasodilators 
Sodium nitroprusside 0.25-10 µg/kg per min as IV infusion (maximal dose for 10 min only) Immediate Nausea, vomiting, muscle twitching, sweating, thiocyanate and cyanide intoxication Most hypertensive emergencies; caution with high intracranial pressure or azotemia Nicardipine hydrochloride 5-15 mg/h IV 5-10 min 1-4 h Tachycardia, headache, flushing, local phlebitis Most hypertensive emergencies except acute heart failure; caution with coronary ischemia Fenoldopam mesylate 0.1-0.3 µg/kg per min IV infusion <5 min 30 min Tachycardia, headache, nausea, flushing Most hypertensive emergencies; caution with glaucoma Nitroglycerin 5-100 µg/min IV infusion 2-5 min 3-5 min Headache, vomiting, methemoglobinemia, tolerance with prolonged use Coronary ischemia Enalaprilat 1.25-5 mg every 6 h IV 15-30 min 6 h Precipitous decrease in pressure in high-renin states; response variable Acute left ventricular failure; avoid in acute myocardial infarction Hydralazine hydrochloride 10-20 mg IV; 10-50 mg IM 10-20 min; 20-30 min 3-8 h Tachycardia, flushing, headache, vomiting, aggravation of angina Eclampsia Diazoxide 50-100 mg IV bolus repeated or 15-30 mg/min infusion 2-4 min 6-12 h Nausea, flushing, tachycardia, chest pain Now obsolete: when no intensive monitoring available Adrenergic inhibitors Labetalol hydrochloride 20-80 mg IV bolus every 10 min; 0.5-2.0 mg/min IV infusion 5-10 min 3-6 h Vomiting, scalp tingling, burning in throat, dizziness, nausea, heart block, orthostatic hypotension Most hypertensive emergencies except acute heart failure Esmolol hydrochloride 250-500 µg/kg per min for 1 min, then 50-100 µg/kg per min for 4 min; may repeat sequence 1-2 min 10-20 min Hypotension, nausea Aortic dissection, perioperative Phentolamine 5-15 mg IV 1-2 min 3-10 min Tachycardia, flushing, headache Catecholamine excess From the National High Blood Pressure Education ProgramIV, Intravenous; IM, intramuscular. *These doses might vary from those in the Physicians’ Desk Reference, 51st ed. Hypotension can occur with all agents. Requires special delivery system.
Cerebrovascular Emergencies
Autoregulation of cerebral blood flow is altered in patients with hypertension particularly in the setting of underlying cerebrovascular disease such that even slight decreases in blood pressure increase the risk of a cerebral ischemic event. The National Institute of Neurologic Disorders and Stroke (NINDS) recommends deferral of treatment of systolic pressures of 185-220mm Hg and/or diastolic pressures of 105-120mm Hg in the absence of other clear indications for immediate intervention. (J Emerg Med 19(4):339, 2000)
AHA recommendations for hemorrhagic stroke is to treat MAP>130 or SBP> 220. Nimodipine is to prevent vasospasm not to treat the BP.
Accelerated-Malignant Hypertension
Most commonly occurs in young black males with renal parenchymal disease or renovascular disease. Ocular findings will be present on fundoscopic exam. Papilledema is the sine qua non of malignant hypertension. If it is absent, then it is accelerated hypertension, but the prognosis is just as bad. Treatment should begin immediately.
Hypertensive Encephalopathy
Triad of htn, altered mental status and papilledema (often) heralds this condition. This state is most likely to occur in previously normotensive patients whose cerebral autoregulatory system is not prepared for the precipitous rise in BP. A CT scan will show characteristic changes.
Secondary Hypertension
Acute Renal Disease
Renal Artery Stenosis-young white women get medial fibroplasia of renal arteries. Can also be seen in blacks and whites often with rapidly progressive disease. ACEI may cause improvement with unilateral stenosis, but failure in bilat.
Glomerulonephritis-IgA (#1 cause), post-Strep, Henoch-Schoenlein Purpura
Scleroderma-Induced Renovascular Hypertension
will have elevated renin
need to give high dose ACEIs
Preeclampsia
From 20 weeks gestation till 2 weeks postpartum
Toxicologic Ingestions
sympathomimetics, MAO interactions
Coarctation of the Aorta
Pheochromocytoma
Tachy, HA, hypertension, check urine metanephrine, serum catecholamines
Give IV phentolamine
Test performance characteristics Data comparing the test performance characteristics of plasma fractionated metanephrines and 24-hour urinary fractionated metanephrines and catecholamine measurements are described here:
In one multicenter cohort study that included 214 patients with confirmed pheochromocytoma and 644 patients who were determined not to have the tumor, (both groups being tested for either sporadic or familial pheochromocytoma), the following characteristics for a number of biochemical tests were reported [30] :
- Sensitivity was highest for plasma fractionated metanephrines (99 percent) followed by urinary fractionated metanephrines (97 percent), urinary catecholamines (86 percent), plasma catecholamines (84 percent), urinary total metanephrines (77 percent), and urinary vanillylmandelic acid (64 percent).
- Specificity was highest for urinary vanillylmandelic acid (95 percent) followed by urinary total metanephrines (93 percent), plasma fractionated metanephrines (89 percent), urinary catecholamines (88 percent), plasma catecholamines (81 percent), and lowest for urinary fractionated metanephrines (69 percent).
- Using receiver operating characteristic curves, sensitivity and specificity values at different upper reference limits were highest for plasma fractionated metanephrines.
(from uptodate 2008)
Hyperaldosteronism
Draw tube for renin and aldosterone
Withdrawal
Outpatient Treatment
NIH’s ALLHAT study shows equal effectiveness between thiazide diuretic (chlorthalidone), lisinopril, and amlodipine for the prevention of MIs and coronary death. The diuretic was more effective at preventing heart failure and more effective than amlodipine at preventing stroke. The ALLHAT study included more minorities than a recent Australian study which showed ACEI are better. Probably the best choice is an ACEI and a diuretic for double therapy in all comers.
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