Hypertensive Emergencies

Last Updated: January 21, 2002

Background: Patients with hypertension in the ED can be classified into 3 categories based upon their symptoms and the organ systems that are affected at the time of presentation.

Hypertensive emergency

Hypertensive emergency, also called hypertensive crisis, is severe hypertension with acute impairment of an organ system (eg, central nervous system [CNS], cardiovascular, renal). In these conditions, the blood pressure (BP) should be lowered aggressively over minutes to hours.

Hypertensive urgency

This is distinguished from hypertensive urgency, in which the BP is a potential risk but has not yet caused acute end-organ damage. These patients require BP control over several days to weeks.

Severe hypertension

The third category, severe hypertension, is elevated BP not yet leading to significant organ damage. In these patients, the hypertension does not necessarily require treatment during the ED visit but does require close follow-up with a primary care physician for long-term BP control. In these cases, beginning antihypertensive therapy in the ED may be appropriate and should be done in consultation with the patient's primary care physician, who will be caring for the patient after the ED visit.

Emergency department considerations

Optimal control of hypertensive situations balances the benefits of immediate decreases in BP against the risk of significant decrease in end-organ perfusion. The emergency physician must be capable of the following:

 

  • Appropriately evaluating patients with an elevated BP

     

  • Correctly classifying the hypertension

     

  • Determining the aggressiveness and timing of therapeutic interventions

     

  • Making disposition decisions

    An important point to remember in the management of the patient with any degree of BP elevation is to "treat the patient and not the number."

     

    Pathophysiology: The 3 major organ systems affected by high BP are the CNS, cardiovascular system, and renal system.

    Central nervous system

    The CNS is affected as the elevated BP overwhelms the normal cerebral autoregulation. Under normal circumstances, with an increase in BP, cerebral arterioles vasoconstrict and cerebral blood flow (CBF) remains constant. During a hypertensive emergency, the elevated BP overwhelms arteriolar control over vasoconstriction and autoregulation of CBF. This results in transudate leak across capillaries and continued arteriolar damage. Subsequent fibrinoid necrosis causes normal autoregulatory mechanisms to fail, leading to clinically apparent papilledema, the sine qua non of malignant hypertension. The end result of loss of autoregulation is hypertensive encephalopathy.

    Cardiovascular system

    The cardiovascular system is affected as increased cardiac workload leads to cardiac failure; this is accompanied by pulmonary edema, myocardial ischemia, or myocardial infarction.

    Renal system

    The renal system is impaired when high BP leads to arteriosclerosis, fibrinoid necrosis, and an overall impairment of renal protective autoregulation mechanisms. This may manifest as worsening renal function, hematuria, red blood cell (RBC) cast formation, and/or proteinuria.

     

    Frequency:
     

    • In the US: More than 60 million Americans, about 25-30% of the population, have hypertension. Of these individuals, 70% have mild disease, 20% moderate, and 10% severe hypertension (diastolic BP [DBP] >110 mm Hg). Approximately 1-2% develop a hypertensive emergency with end-organ damage.

    Mortality/Morbidity: Morbidity and mortality depend on the extent of end-organ damage on presentation and the degree to which BP is controlled subsequently. BP control may prevent progression to end-organ impairment.

    • One-year mortality rate for an untreated hypertensive emergency is greater than 90%.
    • Five-year survival rate among all patients presenting with a hypertensive crisis is 74%.
    • Median survival is 144 months for all patients presenting to the ED with a hypertensive crisis.

    Race: African Americans have a higher incidence of hypertensive emergencies than Caucasians.

    Sex: Males are at greater risk of hypertensive emergencies than females.

    Age: Hypertensive emergencies occur most commonly in middle-aged patients. The peak incidence occurs in those aged 40-50 years.

    CLINICAL

    History: Focus history on the presence of end-organ damage, the circumstances surrounding the hypertension, and any identifiable etiology.

    • Medications
      • Use of hypertensive medications and compliance
      • Use of illicit drugs (specifically alpha-adrenergic agents)
      • Other medication history
    • Duration of hypertension
    • Duration of current symptoms
    • Other medical problems (eg, prior hypertension, thyroid disease, Cushing disease, systemic lupus, renal disease)
    • Date of last menstrual period
    • CNS manifestations
      • Headaches (85%): Mild headache alone in association with elevated BP does not indicate a hypertensive crisis.
      • New-onset blurred vision (60%)
      • Weight loss (75%)

         

      • Nausea and vomiting
      • Weakness and fatigue (30%)

         

      • Confusion and mental status changes
    • Cardiovascular manifestations
      • Symptoms of congestive heart failure (CHF)

         

      • Angina

         

      • Dissecting aneurysm
    • Renal manifestations
      • History of hematuria

         

      • Oliguria
    • Other manifestations
      • Abdominal pain

         

      • Shortness of breath
      • Visual disturbances

    Physical: Use an approach based on organ systems to identify signs of end-organ damage.

    • CNS
      • Focal neurologic findings
      • Seizures, stupor, coma
      • Papilledema, hemorrhages, exudates, or evidence of closed-angle glaucoma
    • Cardiovascular
      • Lung auscultation for evidence of pulmonary edema
      • Signs of CHF, including extra heart sounds
      • Jugular venous distension
      • Peripheral edema
      • Check for equal and symmetric BP and pulses bilaterally.
    • Check for abdominal masses and bruits.

    Causes: The most common hypertensive emergency is a rapid unexplained rise in BP in a patient with chronic essential hypertension.

    • Other causes
      • Renovascular hypertension
      • Eclampsia, pre-eclampsia
      • Acute glomerulonephritis
      • Pheochromocytoma
      • Antihypertensive withdrawal syndromes
      • Head injuries and CNS trauma
      • Renin-secreting tumors
      • Drug-induced hypertension
      • Burns
      • Vasculitis
      • Thrombotic thrombocytopenic purpura
      • Idiopathic hypertension
      • Postoperative hypertension
      • Coarctation of aorta

    DIFFERENTIALS

    Acute Coronary Syndrome
    Aneurysms, Abdominal
    Anxiety
    Congestive Heart Failure and Pulmonary Edema
    Cushing Syndrome
    Delirium Tremens
    Encephalitis
    Glomerulonephritis, Acute
    Headache, Cluster
    Headache, Migraine
    Headache, Tension
    [Hyperthyroidism, Thyroid Storm and Graves Disease]

     Myocardial Infarction
    Pregnancy, Eclampsia
    Pregnancy, Preeclampsia
    Stroke, Hemorrhagic
    Stroke, Ischemic
    Subarachnoid Hemorrhage
    Systemic Lupus Erythematosus
     


     Other Problems to be Considered:

    Steroid use
    Use of over-the-counter or recreational sympathomimetic drugs
    Pheochromocytoma
    Acute vasculitis
    Serotonin syndrome
    Other CNS pathology
    Coarctation of the aorta


    • WORKUP

    Lab Studies:
     
    • CBC
    • Dipstick urinalysis to detect presence of hematuria or proteinuria as evidence of renal impairment
    • Microscopic urinalysis, evaluating for RBCs or RBC casts as evidence of renal impairment
    • Optional studies
      • Toxicology screen
      • Endocrine testing
      • Pregnancy test

    Imaging Studies:
     

    • Chest x-ray - Signs of CHF, pulmonary edema, or coarctation of aorta
    • Head CT scan - Indicated with abnormal neurologic exam to look for intracranial bleeding, edema, or infarction
    • Chest CT scan, transesophageal echo, or aortic angiogram - May be indicated for clinical suspicion of aortic dissection

    Other Tests:
     

    • Electrocardiogram (ECG) to assess for evidence of ischemia or infarction

    TREATMENT

    Prehospital Care:

    • Address the manifestations of a hypertensive emergency, such as chest pain or heart failure. Reduction of BP may not be indicated in the prehospital setting.
    • Oxygen, furosemide (Lasix), and nitrates all may be appropriate.
    • Under most circumstances, attempting to treat hypertension directly in the prehospital setting is unwise. In particular, rapid lowering of BP can critically decrease end-organ perfusion.

    Emergency Department Care: The fundamental principle in determining the necessary ED care of the hypertensive patient is the presence or absence of end-organ damage.

    • Initial considerations (if the patient is not in distress)
      • Place patient who is not in distress in a quiet room and reevaluate after an initial interview. In one study, 27% of patients with an initial DBP >130 mm Hg had their DBP fall below critical levels after relaxation without specific treatment.

         

      • Consider the context of the elevated BP (eg, severe pain often causes increase in BP).
    • Screen for end-organ damage
      • Use historical criteria, physical examination steps, lab studies, and diagnostic tests outlined in Workup.

         

      • Patients with end-organ damage usually require admission and rapid lowering of BP using intravenous (IV) medications. Suggested medication depends on the affected organ system.

         

      • Patients without evidence of end-organ effects may be discharged with follow-up.

         

        • The misconception remains that a patient never should be discharged from the ED with elevated BP. As a result of this belief, patients are given oral medicines, such as nifedipine, in an effort to lower BP rapidly before discharge. This is not indicated and may be dangerous.

           

        • Attempts to temporarily lower BP by using these medicines may result in a precipitous and difficult-to-correct drop in BP. Should this occur, end-organ hypoperfusion may result. Furthermore, patients who present with high BP may have had this elevation for some time and may need chronic BP control but may not tolerate rapid return of BP to a "normal" level.

           

        • Acute lowering of BP in the narrow window of the ED visit does not necessarily improve long-term morbidity and mortality rates. The follow-up recommended for these situations by The Joint National Committee on High Blood Pressure is outlined in Follow-up.

       

    • Rapid BP reduction is indicated in the following circumstances:
      • Acute myocardial ischemia

         

        • Nitroglycerin IV

           

        • Beta-blockers IV

           

        • Angiotensin-converting enzyme (ACE) inhibitors IV

         

      • CHF with pulmonary edema

         

        • Nitroglycerin IV

           

        • Lasix IV

           

        • Morphine IV

         

      • Acute aortic dissection

         

        • Nitroprusside IV plus beta-blockers IV

           

        • Alternative - Trimethaphan IV plus beta-blockers IV
      • Cerebral vascular accident: Lowering BP is indicated in cardiac or renal compromise, DBP >130 mm Hg, hypertensive encephalopathy, or subarachnoid hemorrhage (may require BP control to prevent rebleeding even without other evidence of end-organ damage).

         

        • Nitroprusside IV

           

        • Labetalol IV

           

        • Nimodipine IV
      • Monoamine oxidase (MAO)-tyramine interactions with acute hypertension - Phentolamine IV
    • Reduce BP quickly (over minutes to hours) in the following settings:
      • Pheochromocytoma

         

        • Phentolamine IV

           

        • Nitroprusside IV

           

        • Labetalol IV

         

      • Hypertensive encephalopathy

         

        • Nitroprusside IV

           

        • Trimethaphan IV

           

        • Beta-blockers IV

         

      • Eclampsia

         

        • Hydralazine IV

           

        • Labetalol IV

           

        • Magnesium IV
    • Lowering of BP acutely in the ED in clinical situations other than those listed here is controversial and generally should be avoided.

    Consultations:

    • Consultations may be indicated for comorbid conditions and their definitive treatment.
    • Since hypertension is usually a chronic problem, access to a primary care physician and long-term follow-up are essential for all patients.

    MEDICATION

    Once the diagnosis of a true hypertensive emergency is established and end-organ damage confirmed, the BP should be lowered by up to 25% of the mean arterial pressure (MAP) over minutes to hours. Treat a diastolic reading of 120 mm Hg or greater with an IV antihypertensive medication to prevent cerebral hemorrhage.
     

    Drug Category: Beta-blockers -- These agents are used for hypertensive emergency, especially with aortic dissection and myocardial infarction. They may be used alone or in combination with sodium nitroprusside. Pure beta-blockers should not be used alone in cases that are the result primarily of alpha stimulation (eg, pheochromocytoma, MAOI -tyramine interaction).

    Drug Name
         		 Labetalol (Normodyne) -- Alpha-, beta1-, and beta2-blocker, especially useful with aortic dissection. Lowers BP, reduces incidence of myocardial infarctions and death.
    Adult Dose 2 mg/min continuous infusion to start; titrate up to 5-20 mg/min; not to exceed 300 mg/dose
    Pediatric Dose 0.4-1 mg/kg/h; not to exceed 3 mg/kg/h
    Contraindications Documented hypersensitivity; cardiogenic shock; pulmonary edema; bradycardia; atrioventricular block; uncompensated CHF; reactive airway disease; severe bradycardia
    Interactions Decreases effects of diuretics; increases toxicity of methotrexate, lithium, and salicylates; may diminish reflex tachycardia resulting from nitroglycerin use without interfering with hypotensive effects; cimetidine may increase blood levels; glutethimide may decrease effects by inducing microsomal enzymes
    Pregnancy C - Safety for use during pregnancy has not been established.
    Precautions Caution in impaired hepatic function; discontinue therapy if signs of liver dysfunction; in elderly patients, response rate may be lower and incidence of toxicity higher
    Drug Name
         		 Esmolol (Brevibloc) -- Ideal for use in patients at risk for complications from beta-blockers, especially patients with mild to moderately severe LV dysfunction or peripheral vascular disease. Has short half-life of 8 min; thus, easily titratable to desired effect. In addition, therapy may be stopped quickly if necessary.
    Adult Dose Loading dose: 250-500 mcg/kg infused over 1 min
    Maintenance infusion: 50 mcg/kg/min over 4 min
    If adequate effect not observed within 5 min, repeat loading dose and follow with maintenance infusion using increments of 50 mcg/kg/min (for 4 min); this regimen may be repeated up to 4 times if necessary
    As desired BP approached, skip loading infusion and reduce dose increments in maintenance infusion from 50 mcg/kg/min to 25 mcg/kg/min. If necessary, may increase interval between titration steps from 5-10 min.
    Pediatric Dose Suggested dose: 100-500 mcg/kg administered over 1 min
    Contraindications Documented hypersensitivity; uncompensated CHF; bradycardia; cardiogenic shock; atrioventricular conduction abnormalities
    Interactions Aluminum salts, barbiturates, NSAIDs, penicillins, calcium salts, cholestyramine, and rifampin may decrease bioavailability and plasma levels, possibly resulting in decreased pharmacologic effect; sparfloxacin, astemizole, calcium channel blockers, quinidine, flecainide, and contraceptives may increase cardiotoxicity; digoxin, flecainide, acetaminophen, clonidine, epinephrine, nifedipine, prazosin, haloperidol, phenothiazines, and catecholamine-depleting agents may increase toxicity
    Pregnancy C - Safety for use during pregnancy has not been established.
    Precautions Beta-adrenergic blockers may mask signs and symptoms of acute hypoglycemia and clinical signs of hyperthyroidism; symptoms of hyperthyroidism, including thyroid storm, may worsen when medication abruptly withdrawn; withdraw drug slowly and monitor patient closely

    Drug Category: Alpha-adrenergic blockers -- At low doses, alpha-adrenergic receptor blockers may be used as monotherapy in treatment of hypertension. At higher doses, they may cause sodium and fluid retention. As a result, concurrent diuretic therapy may be required to maintain the hypotensive effects.

    Drug Name
         		 Phentolamine (Regitine) -- Alpha1- and alpha2-adrenergic blocking agent, effective for pheochromocytoma and hypercatecholaminergic-induced hypertension.
    Adult Dose Load 5-20 mg IV q5min or infuse 0.2-0.5 mg/min
    Pediatric Dose 0.05-1 mg/kg/dose IV/IM and repeat q2-4h prn until hypertension controlled
    Contraindications Documented hypersensitivity; coronary or cerebral arteriosclerosis; renal impairment
    Interactions Epinephrine or ephedrine may decrease effects; ethanol increases toxicity
    Pregnancy C - Safety for use during pregnancy has not been established.
    Precautions Caution in tachycardia, peptic ulcer, and gastritis; cerebrovascular occlusions and myocardial infarctions can occur

    Drug Category: Antihypertensive agents -- Sodium nitroprusside is DOC for most hypertensive emergencies. It is potent, rapid in onset, and has a relatively short duration.

    Drug Name
         		 Nitroglycerin (Nitro-Bid) -- Decreases coronary vasospasm, which increases coronary blood flow. Also induces vessel dilatation, decreasing cardiac workload.
    Adult Dose 400 mcg SL tab or spray q5min up to 3 doses
    Alternatively, 5-10 mcg/min IV titrating upward to keep SBP >90 mm Hg or to decrease MAP by 25%
    Pediatric Dose Continuous 0.1-1 mcg/kg/min IV infusion
    Contraindications Documented hypersensitivity; severe anemia; shock; postural hypotension; head trauma; closed-angle glaucoma; cerebral hemorrhage
    Interactions Aspirin may increase serum nitrate concentrations; calcium channel blockers may cause marked symptomatic orthostatic hypotension (dose adjustment of either agent may be necessary)
    Pregnancy C - Safety for use during pregnancy has not been established.
    Precautions Caution in coronary artery disease and low SBP
    Drug Name
         		 Sodium nitroprusside (Nitropress) -- Reduces peripheral resistance by acting directly on arteriolar and venous smooth muscle.
    Adult Dose 0.3-0.5 mcg/kg/min IV initial infusion, increase in increments of 0.5 mcg/kg/min; titrate to desired effect
    Average dose: 1-6 mcg/kg/min; rates >10 mcg/kg/min may lead to cyanide toxicity
    Pediatric Dose Administer as in adults
    Contraindications Documented hypersensitivity; subaortic stenosis, idiopathic hypertrophic; atrial fibrillation or flutter
    Interactions None reported
    Pregnancy C - Safety for use during pregnancy has not been established.
    Precautions Caution in increased intracranial pressure, hepatic failure, severe renal impairment, and hypothyroidism; in renal or hepatic insufficiency, nitroprusside levels may increase and can cause cyanide toxicity; sodium nitroprusside has ability to lower BP and thus should be used only in those patients with MAP >70 mm Hg
    Drug Name
         		 Hydralazine (Apresoline) -- Principal indication is treatment of eclampsia. Decreases systemic resistance through direct vasodilation of arterioles.
    Adult Dose 5-20 mg IV q4-6h prn initial dose; increase dose prn; change to PO ASAP
    Pediatric Dose 0.1-0.2 mg/kg/dose IV q4-6h prn; not to exceed 20 mg or 1.7-3.5 mg/kg/d divided in 4-6 doses
    Contraindications Documented hypersensitivity; mitral valve rheumatic heart disease
    Interactions MAOIs and beta-blockers may increase toxicity; pharmacologic effects may be decreased by indomethacin
    Pregnancy B - Usually safe but benefits must outweigh the risks.
    Precautions Has been implicated in myocardial infarction; caution in suspected coronary artery disease

    FOLLOW-UP

    Further Inpatient Care:
     

    • Close monitoring is required; therefore, an intensive care unit is the most suitable place for admission.
    • Other problems or comorbid conditions need to be addressed appropriately (ie, surgery for aortic dissection).

    Further Outpatient Care:
     

    • Hypertension is a chronic problem. The most important factor in a patient's overall risks of morbidity and mortality is appropriate long-term care.
    • If a patient presents with a high BP but ED evaluation reveals no evidence of end-organ damage, the patient does not need immediate treatment in the ED. Patient does require proper follow-up.
    • The Joint National Committee on High Blood Pressure has published a series of recommendations for appropriate follow-up, assuming no end-organ damage.
      • For a systolic BP 140-159 mm Hg/diastolic 90-99 mm Hg, confirm BP within 2 months.
      • For systolic BP 160-179 mm Hg/diastolic 100-109 mm Hg, evaluate/refer within 1 month.
      • For systolic BP 180-209 mm Hg/diastolic 110-119 mm Hg, evaluate/refer in 1 week.
      • For systolic BP greater than 210 mm Hg/diastolic greater than 120 mm Hg, evaluate/refer immediately.

    Transfer:
     

    • Transfer requirements are based on the ability of the institution to care for the patient and the patient’s associated comorbid conditions.
      • A patient with uncomplicated hypertensive emergency needs only an ICU setting and a physician.
      • Patients with comorbid conditions, such as aortic dissection or subarachnoid hemorrhage, may require transfer to a higher level of care.

    Deterrence/Prevention:
     

    • Good long-term control of hypertension is the best method for prevention of acute hypertensive emergencies.
    • Patient education and close follow-up in patients who have had a hypertensive crisis are essential to prevent recurrent hypertensive emergencies.
    • Proper use of antihypertensive medications by primary care physicians is the major tool in avoiding development of hypertensive emergencies.

    Complications:
     

    • Congestive heart failure
    • Myocardial infarction
    • Renal failure
    • Retinopathy
    • Cerebrovascular accident
    • Abrupt lowering of the BP may result in inadequate cerebral or cardiac blood flow, leading to stroke or myocardial ischemia.

    Prognosis:
     

    • The 1-year mortality rate is higher than 90% for patients with untreated hypertensive emergencies.
    • Median survival duration is 144 months for all patients presenting to the ED with a hypertensive emergency.
    • Five-year survival rate among all patients presenting with hypertensive crisis is 74%.

    Patient Education:
     

    • Patients need continuing education about antihypertensive medications and complications arising from inadequate BP control.
    • Dangers of uncontrolled hypertension must be stressed, including associated serious morbidity and death.
    • Education and maintenance of BP control are important to help prevent further complications.

    MISCELLANEOUS

    Medical/Legal Pitfalls:
     

    • Administering long-acting oral/sublingual medications to acutely lower nonurgent elevations in BP
    • Failure to arrange timely and appropriate follow-up
    • Failure to recognize the serious complications of severe hypertension

    BIBLIOGRAPHY

    • Bennett NM, Shea S: Hypertensive emergency: case criteria, sociodemographic profile, and previous care of 100 cases. Am J Public Health 1988 Jun; 78(6): 636-40[Medline].
    • Calhoun DA, Oparil S: Treatment of hypertensive crisis [see comments]. N Engl J Med 1990 Oct 25; 323(17): 1177-83[Medline].
    • Danish Multicenter Study: Emergency treatment of severe hypertension evaluated in a randomized study. Effect of rest and furosemide and a randomized evaluation of chlorpromazine, dihydralazine and diazoxide. Danish Multicenter Study. Acta Med Scand 1980; 208(6): 473-80[Medline].
    • Ferguson RK, Vlasses PH: Hypertensive emergencies and urgencies. JAMA 1986 Mar 28; DA - 19860418(12): 1607-13[Medline].
    • Houston M: Pathophysiology, Clinical Aspects, and Treatment of Hypertensive Crises. In: Progress in Cardiovascular Diseases 1989; XXXII: 99-148.
    • JNCV: The fifth report of the Joint National Committee on Detection, Evaluation, and Treatment of High Blood Pressure. Arch Intern Med 1993 Jan 25; 153(2): 154-83[Medline].
    • Lavin P: Management of hypertension in patients with acute stroke. Arch Intern Med 1986 Jan; 146(1): 66-8[Medline].
    • Ledingham J: Management of Hypertensive Crisis. In: Hypertension 5 1983; supp III: 114-118.
    • Lip GY, Beevers M, Beevers DG: Complications and survival of 315 patients with malignant-phase hypertension. J Hypertens 1995 Aug; 13(8): 915-24[Medline].
    • McRae RP Jr, Liebson PR: Hypertensive crisis. Med Clin North Am 1986 Jul; DA - 19860724(4): 749-67[Medline].
    • Murphy C: Hypertensive emergencies. Emerg Med Clin North Am 1995 Nov; 13(4): 973-1007[Medline].
    • Panacek E: Controlling Hypertensive Emergencies: Strategies for Prompt, Effective Therapeutic Intervention. In: Emergency Medicine Reports 1992; 13: 53-61.
    • Ram CV: Management of hypertensive emergencies: changing therapeutic options. Am Heart J 1991 Jul; 122(1 Pt 2): 356-63[Medline].
    • Reuler JB, Magarian GJ: Hypertensive emergencies and urgencies: definition, recognition, and management. J Gen Intern Med 1988 Jan-Feb; 3(1): 64-74[Medline].
    • Strandgaard S, Paulson OB: Cerebral autoregulation. Stroke 1984 May-Jun; DA - 19840709(3): 413-6[Medline].

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