- Numerous terms can be used in the literature and often overlap (see Synonyms). Some definitions include a specific diastolic or systolic BP reading, whereas others emphasize an acute change in the BP or the presence of specific clinical syndromes.
- Severe HTN is defined as a diastolic BP of ≥115 mm Hg (15.3 kPa).
- A hypertensive emergency occurs only when an acute elevation of BP causes rapid and progressive end-organ damage, particularly in the cardiovascular, renal, and central nervous systems.
- System(s) affected: Cardiovascular; Nervous; Pulmonary; Renal
- Synonym(s): Hypertensive crisis; Severe HTN; Malignant HTN; Accelerated HTN; Hypertensive emergency
Incidence of hypertensive emergency: 1% of patients with hypertension annually in US.
- Overall prevalence of hypertension in the US 29.3% in 2003–2004 survey data
- Predominant age: Elderly
- History of poorly controlled HTN
- Drug abuse
- Noncompliance with medications
- Genetics: Risk of hypertensive emergency is higher in African Americans.
- Predominant sex: Male > Female
- Treat HTN.
- Counsel the patient on the importance of compliance with antihypertensive treatment and the dangers of stopping the medications abruptly.
- Increased sympathetic tone leads to increased BP.
- Angiotensin II has multiple effects contributing to HTN and end-organ damage:
- Stimulates sympathetic tone, aldosterone release, and antidiuretic hormone release
- Chronic HTN induces vascular thickening and sclerosis.
- Central effects include enhanced resorption of salt and water.
- Chronic HTN shifts autoregulation of BP and cerebral blood flow.
- Renal disease
- Abrupt withdrawal from antihypertensives, especially clonidine (Catapres)
- Withdrawal from CNS depressants
- Appetite suppressants
- Steroids (including oral contraceptives)
- MAOI interaction with certain foods or drugs
- Drugs of abuse; cocaine or amphetamine
- Thrombotic thrombocytopenic purpura (TTP)
- Severe burns
- Postoperative HTN
Commonly Associated Conditions
- Chronic renal failure
- Renovascular HTN
- Acute glomerulonephritis
- Renal vasculitis
Elderly patients may experience isolated systolic HTN due to decreased baroreceptor sensitivity.
- Usually associated with renal disease
- May present with abdominal pain
- Preferred agents for children include labetalol, nicardipine, and nitroprusside.
- Hydralazine is drug of choice because nitroprusside decreases placental blood flow and cyanide metabolite crosses the placenta; may result in fetal toxicity with prolonged exposure.
- Treat preeclampsia.
Clinical presentation will vary depending on organ system affected.
- Altered mental status
- Nausea, vomiting
- Neurologic disturbance
- Shortness of breath, dyspnea, orthopnea
- Chest pain
- Abdominal pain
- Focal neurologic deficits, stupor, coma
- Retinopathy: Funduscopic exam may reveal papilledema, exudates, or hemorrhages.
- Pulmonary edema
- Hemorrhage, thrombosis, embolus
- Renal or abdominal bruit
- Unequal blood pressure or pulses in the extremities
Diagnostic Tests & Interpretation
Initial lab tests
- Urinalysis and renal function tests (red cell casts, hematuria, proteinuria are all common)
- Urine drug screen in selected patients
- Blood count and smear may indicate microangiopathic hemolytic anemia or thrombocytopenia.
- Serum electrolytes, which may indicate hypokalemic alkalosis
- Creatinine clearance
- Calcium, glucose
Follow-Up & Special Considerations
Subsequent workup pheochromocytoma in selected patients
- Chest radiograph:
- May show pulmonary edema and cardiomegaly due to CHF
- Mediastinal widening and blunting of the aortic knob consistent with aortic aneurysm (potential rupture)
- If CNS symptoms, get head CT or MRI.
- If chest, abdominal, or back pain, consider contrast CT or MRI for suspected aortic dissection.
Follow-Up & Special Considerations
Subsequent workup for aldosteronism and for renal artery stenosis may be indicated in selected patients, especially young patients who may have fibromuscular dysplasia.
- ECG may reveal ischemia or left ventricular hypertrophy.
- The BP should be measured with an appropriately sized cuff, with ≥2 readings from both arms; then average readings.
Extreme BP elevations can overwhelm the autoregulatory mechanisms for organ blood flow, resulting in damage to the arteriolar and capillary beds. This process produces organ hemorrhages and edema.
- Myocardial infarction or angina pectoris
- Aortic dissection
- Other CNS pathology (e.g., encephalopathy)
- Acute pulmonary edema
- Renal failure
A 2008 Cochrane Review (1) noted that there are no randomized clinical trials showing a reduction in mortality from the recommended treatments, and similarly no clear randomized trial basis for recommending one medication over another. However, the recommended medications have been shown to reduce blood pressure in these circumstances, and the evidence levels reflect their effectiveness in this regard.
- IV unless otherwise indicated:
- Nitroprusside (Nipride, Nitropress): Infusion 0.5–10 µg/kg/min; contraindicated in pregnancy (2,3)[A]
- Fenoldopam (Corlopam): 0.1 µg/kg/min IV initial dose. Increase by 0.1 µg/kg/min q15 minutes to desired effect. Maximum dose 1.6 mcg/kg/min (4)[A].
- Hydralazine: Bolus 5–15 mg; preferred in pregnancy (2,3,5)[A]
- Labetalol (Normodyne, Trandate): Bolus 20–80 mg q10–15 minutes; infusion 0.5–2.0 mg/min (2,3)[A]
- Nitroglycerin (NTG): Infusion 5–100 µg/min (2,3,5)[A]
- NTG: 0.4 mg SL tablet. Repeat q5 minutes if needed. Consider IV infusion after 3 doses (2)[B].
- Phentolamine (Regitine): Bolus 5–10 mg q5–15 minutes (2,3)[A]
- Esmolol: 0.05–0.3 mg/kg/min (2,3,5)[A]
- Enalapril: 0.625–1.25 mg (2,3)[B]
- Nicardipine: 4–15 mg/h (2,3,6)[B]
- The drug(s) used depends on the end organs affected and the patient’s clinical status:
- Hypertensive encephalopathy: Nicardipine, labetalol, esmolol, or enalaprilat (3)[A]
- CNS events: Nicardipine, labetalol. In ischemic stroke, withhold treatment unless systolic >220 or diastolic >120, except where needed for treating concomitant cardiovascular disease or pulmonary edema (2,3,5)[A].
- Subarachnoid hemorrhage: Nicardipine, labetalol, or esmolol (3,5)[A]
- Myocardial ischemia: Nitroglycerin infusion; or labetalol, or esmolol (2,3,5)[A]
- CHF: Nitroprusside infusion; or nitroglycerin infusion; or enalaprilat or nicardipine (2,3)[A]
- Aortic dissection: Nitroprusside and β-blocker, esmolol or nitroglycerin infusion (2,3,5)[A]
- Renal failure: Nitroprusside, labetalol, or nicardipine. Consider dialysis (2,5)[A].
- Pheochromocytoma: Phentolamine; or labetalol; or nitroprusside infusion (2)[A]
- Antihypertensive withdrawal: Labetalol or phentolamine (2)[A]
- Interactions between MAOIs and foods or drugs: Phentolamine or labetalol (2)[B]
- Eclampsia/preeclampsia: Hydralazine, labetalol, or oral nifedipine (2,3,5)[A]
- Oral clonidine: Oral loading dose of 0.2 mg followed by 0.1 mg/h until BP has been lowered or a total dose of 0.8 mg has been administered (2,5)[B]
- Trimethaphan (Arfonad): Infusion 0.5–5 mg/min (2)[B]
- Diazoxide in eclampsia/preeclampsia: 15 mg bolus every 3 minutes to maximum dose of 300 mg (7)[B]
- The general goal is to lower the mean arterial pressure (MAP) by ∼20% or reduce the diastolic pressure to 100–110 mm Hg (13.3–14.6 kPa) over 1 hour.
- MAP is ∼1/3 of the sum of twice the diastolic pressure plus the systolic pressure.
- If ongoing end-organ damage is thought to be secondary to the hypertensive state, prompt treatment with IV medication is indicated. Monitor patient closely so that a rapid fall in BP can be avoided.
Complementary and Alternative Medicine
Comfortable environment, which may lower the BP
- An arterial catheter may be used to monitor BP.
- Advantage over noninvasive monitoring not clearly proven (5)[C]
In general, lower the BP no more than 20% in the 1st hour; then, if stable, lower to 160/100–110 in the next 2–6 hours.
- All patients with true hypertensive emergencies should be hospitalized.
- Associated end-organ effects may require specific treatment (e.g., acute myocardial infarction).
Fluid restriction may be appropriate for associated pathology such as pulmonary edema.
Patient should be stabilized on oral antihypertensives as appropriate (6)[A].
Close outpatient follow-up with primary care physician recommended to ensure ongoing control of HTN.
- Follow BP closely to avoid a rapid drop.
- Begin oral therapy as soon as possible after BP control has been achieved with IV medications.
- Ongoing BP control plus monitoring of affected organ system(s) (e.g., renal function) for evidence of continued morbidity
- Avoid abrupt discontinuation of antihypertensive medicines.
- Stress importance of compliance.
- Emphasize the lack of symptoms with HTN until organ damage occurs.
- BP should return to acceptable levels within 24 hours.
- Long-term prognosis depends upon extent of secondary end-organ damage in addition to ongoing BP control.
- Complications depend upon organ system(s) secondarily affected.
- Abrupt or excessive lowering of BP may result in inadequate cerebral or cardiac blood flow, leading to stroke or myocardial ischemia.
- The benefits of aggressive treatment may outweigh the risks in patients with severe HTN but no end-organ damage. No studies have proven that aggressive treatment reduces the risk of long-term morbidity or mortality from hypertensive urgencies.
1. Perez MI, Musini VM. Pharmacological interventions for hypertensive emergencies. Cochrane Database Syst Rev. 2008:CD003653.
2. Flanigan JS, Vitberg D. Hypertensive emergency and severe hypertension: what to treat, who to treat, and how to treat. Med Clin North Am. 2006;90:439–51.
3. Shayne PH, Pitts SR. Severely increased blood pressure in the emergency department. Ann Emerg Med. 2003;41:513–29.
4. Tumlin JA, Dunbar LM, Oparil S, et al. Fenoldopam, a dopamine agonist, for hypertensive emergency: a multicenter randomized trial. Fenoldopam Study Group. Acad Emerg Med. 2000;7:653–62.
5. Management of hypertension and hypertensive emergencies in the emergency department: The EMREG-International Consensus Panel Recommendations. Ann Emerg Med. 2008;51(3):S1–S38.
6. Chobanian AV, Bakris GL, Black HR, et al. The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7 report. JAMA.2003;289:2560–72.
7. Hennessy A, Thornton CE, Makris A, et al. A randomised comparison of hydralazine and mini-bolus diazoxide for hypertensive emergencies in pregnancy: The PIVOT trial. Aust N Z J Obstet Gynaecol.2007;47:279–85.
Cherney D, Straus S. Management of patients with hypertensive urgencies and emergencies: a systematic review of the literature. J Gen Intern Med. 2002;17:937–45.
Decker WW, Godwin SA, Hess EP, et al. Clinical policy: critical issues in the evaluation and management of adult patients with asymptomatic hypertension in the emergency department. Ann Emerg Med.2006;47:237–49.
Marik PE, Varon J. Hypertensive crises: challenges and management. Chest. 2007;131:1949–62.
See Also (Topic, Algorithm, Electronic Media Element)
Aortic Dissection; Pre-Eclampsia and Eclampsia (Toxemia of Pregnancy); Hypertension, Essential; Pheochromocytoma
401.9 Unspecified essential hypertension
38341003 Hypertensive disorder, systemic arterial (disorder)
- Treatment of severe HTN (hypertensive urgency) without evidence of acute end-organ damage is controversial. No emergent treatment is recommended.
- Avoid rapid prehospital lowering of BP.
- Treatment depends upon the organ systems affected.
- Esmolol and ACE inhibitors are contraindicated in pregnancy.