Topic Editor: Grant E. Fraser, M.D., FRACGP, FACRRM, ASTEM

Review Date: 12/29/2012

Definition

A hypertensive crisis is an acute increase in blood pressure (BP) with a systolic blood pressure (SBP) greater than 180 mm Hg or a diastolic blood pressure (DBP) greater than 120 mm Hg. When accompanied by impending or actual target organ dysfunction, it is termed Hypertensive Emergency (HE). When there is no evidence of target organ damage, it is termed hypertensive urgency. Malignant hypertension is an older terminology for HE.
This topic focuses on hypertensive emergency in adults who are not pregnant and do not have spinal cord injury.

Description

• Hypertensive emergency (HE) or malignant hypertension, is generally an acute condition characterized by severe BP elevation of at least 180/120 mmHg (most commonly with DBP>140 mmHg), with evidence of, or impending target organ damage, such as:
• Acute left ventricular failure with pulmonary edema
• Acute myocardial infarction (AMI)
• Acute renal injury
• Dissecting aortic aneurysm
• Hypertensive encephalopathy
• Intracerebral hemorrhage
• Retinal hemorrhages, exudates and/or papilledema
• Unstable angina pectoris
• Patients with pre-existing hypertension, blacks, and current smokers may be at higher risk
• The pathophysiology is not certain. However, it appears as though a loss of auto-regulation within the arterial walls occurs; generally due to prolonged exposure to hypertensive conditions. This excessive pressure on vessel walls results in release of vasoconstrictors with an abrupt increase in systemic vascular resistance and blood pressure. The effect of this is endothelial injury, activation of the coagulation cascade and platelets, fibrinoid necrosis of arterioles, and fibrin deposits. The onset of ischemic injury releases further vasoconstrictors which continues the cycle. Leakage of fluid into the extracellular space occurs, along with micro-hemorrhages and end organ damage
• Uncontrolled hypertension, abrupt stopping of antihypertensive medications (usually alpha or beta blockers), and abuse of stimulant drugs are the major causes of HE

Epidemiology

Incidence/prevalence

• More than 1 billion people worldwide have chronic hypertension and >65 million people in the US
• Approximately 1% of hypertensive patients will have HE at some time

Age

• Peak incidence is among those aged 40-50 years

Gender

• Men with hypertension have a two-fold risk compared to women

Race

• HE is more prevalent in the African Americans

Risk factors for getting condition

• African Americans
• Chronic hypertension
• Current tobacco smokers
• Drug abuse (stimulants intoxication or withdrawal from alcohol or sedative-hypnotics)
• Male gender
• Medication noncompliance
• Poorly controlled or untreated chronic hypertension

Etiology

• HEs are due to idiopathic elevations in BP or as a complication of essential or secondary hypertension
• Acute exacerbation of chronic hypertension and nonadherence to antihypertensive medication are the major stimulants for HEs
• Other etiological agents include renal parenchymal disease, excessive catecholamine states such as pheochromocytoma, adrenocortical tumors, and monoamine oxidase inhibitors (MAOI) interactions with tyramine
• Antihypertensive medication withdrawal (generally alpha and beta blockers) may also cause a rebound effect leading to hypertensive emergencies
• Secondary causes of HC may include use of drugs such as oral contraceptives, amphetamines, cocaine, ecstasy, phencyclidine, linezolid, nonsteroidal anti-inflammatory drugs, corticosteroids, and heavy metals
• Other causes include pregnancy-induced hypertension, preeclampsia, and autonomic dysfunction, including autonomic dysreflexia in spinal cord injured patients

History

• Manifestations of HE differs between patients depending upon etiology, age and comorbidities
• Historical items of importance include:
• Details of past history of hypertension, prescription medication use, and if on medications for hypertension; which type(s) and compliance with medications
• Use of over the counter medications or herbal compounds
• Use of recreational drugs (especially amphetamines, cocaine, ecstasy, phencyclidine)
• Drug withdrawal states (alpha/beta blockers, alcohol, benzodiazepines, or barbiturates)
• Patients with hypertensive encephalopathy, a serious complication of HE, may have headache, altered level of consciousness, and/or focal neurologic signs
• Some patients may exhibit cardiovascular symptoms which may include chest pain (angina, aortic dissection, acute myocardial infarction), or have symptoms of acute left ventricular failure such as weakness, dyspnea, orthopnea, cough with clear phlegm
• If acute renal injury has occurred, there may be history of oliguria and/or hematuria

Physical findings on examination

• Physical examination should be performed to identify signs of end-organ damage
• Examine pulses in all extremities
• Auscultate the lungs for signs related to pulmonary edema
• Auscultate the heart for murmurs or gallops, and the renal arteries for bruits
• Conduct a focused neurological examination. Focal neurologic deficits, and lateralized focal signs in particular, may raise concern for intracranial hemorrhage
• Patients with hypertensive encephalopathy may present with retinopathy with arteriolar changes, hemorrhages, exudates, and/or papilledema

Blood tests findings

• Complete blood count (CBC), electrolytes, blood urea nitrogen, and creatinine levels should be tested in all patients with hypertensive crises to evaluate renal function and electrolyte abnormalities

Other laboratory test findings

• Urinalysis for detection of hematuria or proteinuria

Radiographic findings

• Plain chest radiographs are recommended in patients presenting with chest pain or shortness of breath. Findings of interest can include pulmonary edema and cardiomegaly due to congestive heart failure (CHF), or widened mediastinum and abnormal aortic knob due to thoracic aortic aneurysm
• Chest CT or MRI is performed in suspected cases of aortic dissection
• Head CT or MRI is recommended in cases of altered mental status, focal neurologic abnormality, or significant headache

Othertests

• Electrocardiogram (ECG) may show coronary ischemia,acute infarction, or left ventricular hypertrophy

• Acute coronary syndrome
• Acute pulmonary edema
• Aortic dissection
• Catecholamine excess: pheochromocytoma, cocaine/sympathomimetic drug intoxication, tyramine ingestion in patients on an MAOI
• Congestive heart failure
• Intracerebral hemorrhage
• Myocardial infarction
• Preeclampsia/eclampsia
• Renal failure
• Stroke
• Subarachnoid hemorrhage
• Withdrawal syndrome from alpha or beta blocking agents
• Withdrawal syndrome from cessation of alcohol, barbiturates, benzodiazepines

General treatment items

• Hypertensive urgency
• Most of these patients are poorly compliant or inadequately treated chronic hypertensives
• Patients with hypertensive urgency can be given oral medication with gradual blood pressure (BP) reduction over 12-24 to 48 hrs. The goal is to reduce BP to around 160/100 mm Hg over hours to days with close outpatient followup
• Commonly utilized agents include oral ace-inhibitors, alpha, beta or calcium channel blockers
• It is important to avoid use of parenteral antihypertensives or use of high-loading doses of oral drugs. The goal is gradual lowering of BP, as precipitous falls have significant risk
• Follow-up on an outpatient basis should generally be arranged within 24-48 hours. Some patients who are higher risk, such as diabetics, prior stroke, significant coronary artery disease or severe renal disease; or medication noncompliance may warrant further observation
• Hypertensive emergencies
• Hypertensive emergency (HE) is generally admitted to an intensive care unit for close monitoring and administration of parenteral titratable antihypertensive medications, along with continuous monitoring of BP, cardiovascular and neurologic status, and urine output
• It is important to note that blood pressure lowering recommendations only apply to patients who have not had acute stroke (hemorrhagic or ischemic) as different recommendations for blood pressure management should be followed in that setting
• Treatment of HE should include:
• Use of parenteral titratable agents to lower BP by no more than 25% within the first hour
• Thereafter, within the next 2-6 hours, if the patient is stable and not showing evidence of organ hypoperfusion, gradual lowering to a goal of 160/100-110
• Thereafter, over the ensuing 24-48 hours, goal to achieve a normal blood pressure and wean parenteral agents with gradual addition of oral agents for BP control, along with close monitoring for complications
• Medications preferred are rapid acting antihypertensive medications such as nitroprusside (favored as an initial agent for rapid onset, titratable and rapid offset), esmolol, labetalol, nicardipine, clevidipine, fenoldopam, nitroglycerin, hydralazine, and phentolamine
• Volume-expansion with intravenous saline may be advised in patients with normal kidney function if they present with volume depletion. This helps to reduce renin secretion and prevent hypotension once vasodilating drugs are administered
• In cases of aortic dissection, the goal is a reduction of the pressure impulse, and to achieve a rapid reduction of systolic blood pressure (SBP) to less than 120 mm Hg and mean arterial pressure less than 80 mm Hg within 5-10 minutes. Generally nitroprusside or nitroglycerin infusion with beta blocker (preferably esmolol) is administered and carefully titrated
• Enalaprilat is generally not recommended due to slow onset, a long duration of action, and risk of aggravation of renal failure which may be present in patients with HE
• Hydralazine can be used in pregnant women in addition to other options such as labetalol, nicardipine, methyldopa, nifedipine, and prazosin

Medications indicated with specific doses

Antihypertensive agents

• Clevidipine [IV]
• Adult Dosing
• Enalaprilat [IV]
• Adult Dosing
• Esmolol [IV]
• Adult Dosing
• Fenoldopam [IV]
• Adult Dosing
• Hydralazine [IM/IV]
• Adult Dosing
• Labetalol [IV]:
• Adult Dosing
• Nicardipine [IV]
• Adult Dosing
• Nitroglycerin [IV]
• Adult Dosing
• Nitroprusside [IV]
• Adult Dosing
• Phentolamine [IM/IV]
• Adult Dosing

Dietary or Activity restrictions

• Patients should maintain a low-sodium diet and remain well hydrated (except in pulmonary edema)
• In patients with cardiac, renal or CNS complications, the diet should be modified for such underlying conditions
• Bed rest with limited activity is advisable until the hypertensive emergency is adequately controlled. Thereafter, normal activity should be encouraged once the condition is under control

Disposition (Admission and Discharge criteria)

• Admission Criteria
• HE generally requires admission to the intensive care unit for close monitoring and titration of appropriate antihypertensive agents
  
• Discharge Criteria
  Patients can be discharged if they fulfill following criteria
• Any end organ damage stabilized
• Blood pressure controlled or stable dose oral agents
• Follow-up arranged, generally within 7 days as an outpatient
• Home monitoring of blood pressure arranged (highly preferred but not essential)
• If clear precipitating event (e.g. elicit drug use, medication non-compliance, etc) present, addressed and measures taken to prevent recurrence

Monitoring

• Home monitoring of BP is recommended with results to be brought to primary care physician
• Regular monitoring following hospital discharge is required with intervals of visits adjusted as appropriate by the primary care physician (for monitoring of BP and medications side effects, clinical efficacy and patient compliance)
• Monitoring of any organ dysfunction that occurred during the HE may be required post discharge on a case by case basis (e.g. significant renal failure)

Complications

• End organ hypoperfusion can occur with abrupt or excessive lowering of BP; leading to life-threatening complications such as stroke or myocardial ischemia
• Renal failure, intracranial hemorrhage, heart failure, pulmonary edema, acute myocardial infarction are the most common complications associated with HE
• In the case of eclampsia, seizure and maternal/fetal demise are major concerns

Prevention

• The first critical step in preventing HE is adequate screening and treatment of essential hypertension
• HE may be prevented with appropriate ongoing monitoring and treatment of known hypertensive patients, along with encouraging compliance with recommended medical regimen
• Smoking cessation
• Eliminate triggering factors to reduce risk for HE (sudden cessation of alpha or beta blockers, cessation of alcohol or sedative-hypnotics, use of stimulants)
• Diet modification, weight loss, and lifestyle changes play a crucial role in maintaining control of essential hypertension and thus preventing HE

Prognosis

• HE is associated with poor prognosis unless promptly treated. One year mortality rate in untreated cases of hypertensive emergency is 79% and 5-year survival rate among all patients who present with hypertensive crisis is 74%
• One study indicates that 5-year post HE survival is improving. This may be due to lower target levels of BP , strict BP control, and availability of new classes of antihypertensive drugs
• Rate of renal survival has also improved (5-year, 84%; 10-year, 72%) in patients with HE

Associated conditions

• Acute glomerulonephritis
• Atheromatous embolization of kidney
• Chronic glomerulonephritis
• Chronic pyelonephritis
• Congenital small kidney
• Cushing's disease
• Drug abuse (stimulants)
• Essential hypertension
• Hydronephrosis
• Nephroclacinosis
• Polyarteritis nodosa
• Post pregnancy
• Scleroderma
• Tuberculous and polynephritic kidney
• Tyramine ingestion with MAOI use
• Unilateral renal artery obstruction

Pregnancy/Pediatric affects on condition

• HE may be fatal to both mother and baby
• Diastolic blood pressure should be maintained greater than 90 mmHg to allow for adequate utero-placental perfusion
• Antihypertensives in pregnancy should achieve a BP of less than160/105 mmHg to prevent acute hypertensive complications such as cerebral hemorrhage in the mother
• Magnesium sulfate (for eclampsia/pre-eclampsia) should be considered
• Agents for hypertension in pregnancy usually include either injectable labetolol or hydralazine initially. Additional agents may include methyldopa, oral nifedipine and/or oral beta blockers
• Children with hypertensive emergencies usually have associated conditions such as renal disease. Labetalol, nicardipine, and nitroprusside are common agents of choice for BP control. The diagnosis of hypertensive emergency in children will use significantly lower numerical values of BP (based upon normal range for age) for both diagnosis and as goals for therapeutic response

Synonyms/Abbreviations

Synonyms

• Accelerated hypertension
• Hypertensive crisis
• Malignant hypertension
• Uncontrolled hypertension

ICD-9-CM

• 401.0 Malignant essential hypertension
• 401.1 Benign essential hypertension
• 401.9 Unspecified essential hypertension

ICD-10-CM

• I10 Essential (primary) hypertension
• I67.4 Hypertensive encephalopathy

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