A hypertensive emergency is severe hypertension with manifestations of damage to target organs (primarily the brain, eyes, cardiovascular system, and kidneys). Hypertensive emergencies are relatively rare in children, occurring in approximately 2 per 10,000 emergency department visits (1). Diagnosis is by blood pressure measurement and tests for target organ damage, including ECG, urinalysis, and serum blood urea nitrogen and creatinine measurements. Treatment is immediate blood pressure reduction, typically with IV medications.
(See also Hypertension in Children and Hypertensive Emergencies in adults.)
Acute severe hypertension is an increase, usually rapid, in blood pressure (BP) that is both life threatening and has the potential to cause target organ damage. Acute severe hypertension is also referred to as "hypertensive crisis" and can be further divided into hypertensive urgencies and hypertensive emergencies. Hypertensive urgency is an episode of acute severe hypertension without evidence of target organ damage while hypertensive emergency is a similar elevation increase associated with target organ damage. A hypertensive urgency can become an emergency, and thus the distinction between the two terms is imprecise, and the preferred term is acute severe hypertension. However, the terms "urgency" and "emergency" are still used in clinical practice.
In adults and adolescents (> 13 years), BP exceeding 180/120 mm Hg fulfills criteria for severe hypertension; however, there is no analogous discrete BP cutoff for younger children. The American Academy of Pediatrics' guidelines suggest that physicians should be concerned about acute target organ damage in patients whose blood pressure (BP) measurement is ≥ 30 mm Hg above the 95th percentile based on age, sex, and height (see BP percentile level tables for boys and girls) (2). For these levels of severe hypertension, applying the term "hypertensive emergency" to children with target organ dysfunction or damage (primarily of the heart, brain, and/or kidneys) and applying the term "hypertensive urgency" to children with no symptoms and no target organ manifestations may help direct care because children with a hypertensive emergency need to be moved quickly to an emergency department or intensive care unit for evaluation, rapid testing, close monitoring, and IV treatment. Children with a hypertensive urgency also need to be quickly evaluated and treated by a physician who has experience treating children with severe hypertension, but BP does not need to be lowered as rapidly because these patients may have long-standing hypertension (which is why they do not have symptoms), and, at times, oral medications can be used.
Importantly, children with acute secondary hypertension (particularly due to acute glomerulonephritis) can be symptomatic and even develop encephalopathy at BP levels that would be considered mild in an adult or adolescent with hypertension because, in addition to the BP level, the rate of rise is important because there is less time for the organ systems to adapt to the hypertension.
General references
1. Wu HP, Yang WC, Wu YK, et al: Clinical significance of blood pressure ratios in hypertensive crisis in children. Arch Dis Child 97(3):200–205, 2012. doi: 10.1136/archdischild-2011-300373
2. Flynn JT, Kaelber DC, Baker-Smith CM, et al: Clinical practice guideline for screening and management of high blood pressure in children and adolescents. Pediatrics 140(3):e20171904, 2017. doi: 10.1542/peds.2017-1904
Etiology of Acute Severe Hypertension in Children
Hypertensive emergencies are usually the result of a rapid rise in BP, which may develop in children regardless of whether they have been previously diagnosed with hypertension.
The causes of acute severe hypertension vary significantly by age:
Infancy: Congenital renal disease, renal vascular disease, bronchopulmonary dysplasia, coarctation of the aorta, renal vein thrombosis
Childhood: Renal parenchymal disease, renal vascular disease, endocrine disorders, medication- or toxin-induced hypertension
Adolescence: Renal parenchymal disease; primary hypertension sometimes with nonadherence to treatment; use of medications and substances such as stimulants, anabolic steroids or corticosteroids, certain oral contraceptives, or certain illicit drugs (eg, cocaine, amphetamines)
Symptoms and Signs of Acute Severe Hypertension in Children
BP is markedly elevated, typically to stage 2 hypertension levels or higher (see table Classification of Blood Pressure in Children).
In children with severe hypertension, manifestations range from entirely asymptomatic to severe symptoms and functional impairment. Some of the variation may be related to age. Infants and young children tend to present with nonspecific findings such as irritability, poor feeding, or growth and weight faltering. There is some evidence that younger children (≤ 6 years) are more likely than older children to present with change of consciousness or seizure activity. Older children who are able to communicate their symptoms may report headache, acute visual changes, dizziness, chest discomfort, or nausea and vomiting. Although uncommon, orthopnea, shortness of breath, and edema may suggest concomitant heart failure or kidney failure.
Complications associated with acute severe hypertension are typically related to the cardiac, renal, and central nervous systems:
Heart: Left heart failure
Brain: Hypertensive encephalopathy
Kidneys: Acute kidney injury (elevated creatinine) or proteinuria
By definition, all children with a hypertensive emergency present with overt evidence of target organ damage. In children with a hypertensive urgency, subclinical target organ damage, such as left ventricular hypertrophy, hypertensive retinopathy, or microalbuminuria, may be present.
Diagnosis of Acute Severe Hypertension in Children
Blood pressure (BP) measurement and monitoring
Laboratory testing and imaging for target organ involvement
Elevated BP should be measured using the proper technique for children. In a hypertensive emergency, BP measurements are usually taken with an oscillometric device, which facilitates the frequent (as often as every 2 to 3 minutes) measurements required. However, the initial measurement should be confirmed by auscultation.
Clinical assessment of any child with hypertensive urgency or emergency should include a detailed history and physical examination.
Risk factors for hypertension should be assessed, as these may provide clues to the etiology of the hypertension. History should include recent medication changes or exposures, as well as more remote factors, such as perinatal events including premature birth or umbilical artery catheterization. A history of urinary tract infections or frequent febrile illnesses as a young child raises the possibility of renal scarring or reflux nephropathy. In adolescent girls, pregnancy must be considered. Episodes of flushing, pallor, diaphoresis, and palpitations may suggest an underlying endocrine or metabolic disorder.
A thorough physical examination is mandated with careful attention not only to possible clues as to the underlying etiology of the BP elevation but also to findings that may be indicative of target organ damage or comorbid conditions. Similar goals hold true for laboratory testing and diagnostic imaging. The typical approach to a child with confirmed hypertension tends to be measured with subsequent completion of additional studies as indicated based on the clinical situation. However, the higher degree of acuity in children who present with hypertensive crisis typically demands a more expansive approach to initial testing to identify the cause of hypertension detect target organ damage expeditiously
Initial testing may include a variety of laboratory testing and/or diagnostic imaging.
Laboratory testing includes:
Complete blood count (CBC)
Electrolytes, blood urea nitrogen (BUN), and creatinine
Urinalysis
Thyroid function tests
Cortisol
Fractionated plasma metanephrines
Urine catecholamines
Pregnancy test
Toxicology screen
Diagnostic imaging may include:
Renal ultrasound with Doppler
Echocardiogram
Chest radiograph
Nuclear medicine renal scan (technetium-99m dimercaptosuccinic acid [Tc-99m DMSA] or technetium-99m mercaptoacetyltriglycine [Tc-99m MAG3])
Computed tomography (CT) angiography, magnetic resonance (MR) angiography, digital subtraction angiography
Metaiodobenzylguanidine (MIBG) scanning
Brain imaging (CT or MRI)
Although results from such studies help inform eventual therapeutic options to control BP over the long term, initiation of antihypertensive medications should never be delayed in deference to testing.
Treatment of Acute Severe Hypertension in Children
Admission to intensive care unit if available; or stabilization in the emergency department
Immediate treatment with short-acting antihypertensive medications
Intravenous access and, sometimes, arterial blood pressure monitoring
Thorough evaluation for target organ damage
The American Academy of Pediatrics guideline recommends a BP treatment goal in acute severe hypertension of "around the 95th percentile," although prior guidelines recommended lowering BP to less than the 95th percentile in children with hypertension and no target organ damage and to less than the 90th percentile in children with target organ damage, secondary hypertension, and/or comorbid conditions such as underlying kidney disease, heart disease, or diabetes (1, 2).
In patients with hypertensive emergency, the BP should be lowered gradually, over days rather than hours. Patients with chronic hypertension in particular have cerebral autoregulatory mechanisms that have adapted to protect the brain from ischemic damage, which cannot tolerate a rapid drop in BP. Thus, rapid lowering of the BP can lead to cerebral hypoperfusion and ischemia, which in some cases, can cause temporary or permanent neurologic dysfunction. Rapid reduction in BP may also lead to kidney hypoperfusion and ischemia, resulting in acute kidney injury and potentially chronic kidney disease.
A reasonable approach to BP control in children with acute severe hypertension is to reduce the BP by 25% of the total planned decrease over the first 8 to 12 hours, reduce it by a further 25% over the next 8 to 12 hours, and reduce it by the final 50% over the following 24 hours (3); hence, the time period for controlled reduction to the goal BP is~ 48 hours. It may be difficult to reach the goal BP in the first 48 hours, especially in patients with secondary hypertension; additional therapy may be required over the following days to reduce the blood pressure adequately.
All patients with hypertensive emergency require intravenous access for medication and fluid administration. Arterial access is optimal for continuous arterial BP monitoring in the intensive care unit, emergency department, or other location of care. For initial treatment, intravenous antihypertensive agents, such as nicardipine (via continuous infusion) and labetalol (via continuous infusion or intermittent dosing), are preferred as these are reliable to administer, act rapidly, and can be titrated fairly quickly to achieve BP targets. Other potential options include esmolol or nitroprusside infusions and intermittent hydralazine.All patients with hypertensive emergency require intravenous access for medication and fluid administration. Arterial access is optimal for continuous arterial BP monitoring in the intensive care unit, emergency department, or other location of care. For initial treatment, intravenous antihypertensive agents, such as nicardipine (via continuous infusion) and labetalol (via continuous infusion or intermittent dosing), are preferred as these are reliable to administer, act rapidly, and can be titrated fairly quickly to achieve BP targets. Other potential options include esmolol or nitroprusside infusions and intermittent hydralazine.
Once BP is controlled initially by rapidly acting IV medications, patients are transitioned to oral antihypertensives. The choice of oral agent is based on the initial response to IV agents, the cause of the acute severe hypertension, and other patient characteristics. Oral agents may also be considered for initial BP control if life-threatening complications are absent and they can be tolerated by the patient, or if intravenous access is difficult or delayed (4). (See tables Intravenous Medications for Children With Severe Hypertension and Symptoms or Signs of Target Organ Damage and Oral Medications for Children With Asymptomatic Severe Hypertension.)
Intravenous Medications for Children With Severe Hypertension and Symptoms or Signs of Target Organ Damage
Medication (Class) | Dose | Adverse Effects | Comments |
|---|---|---|---|
First-line medications | |||
Labetalol (combined alpha- and beta-adrenergic blocker)Labetalol (combined alpha- and beta-adrenergic blocker) | Infusion: 0.25–3 mg/kg/hour IV; Initiate at low end dose and gradually titrate as needed to control blood pressure Bolus: 0.2–1 mg/kg IV every 10 to 20 minutes, increasing up to 40 mg/dose if needed | May cause bradycardia, wheezing | Relative contraindications for or caution should be used in patients with asthma or heart failure. |
Nicardipine (calcium channel blocker)Nicardipine (calcium channel blocker) | Infusion: Initially 0.5–1 mcg/kg/minute IV (may give initial one-time bolus of 30 mcg/kg not to exceed 2 mg prior to infusion) titrate upward every 15 to 30 minutes to maximum 4 mcg/kg/minute | May cause reflex tachycardia May raise cyclosporine/tacrolimus levelsMay raise cyclosporine/tacrolimus levels | Nicardipine is better for infants, children with lung disease, or children with significant asthma.Nicardipine is better for infants, children with lung disease, or children with significant asthma. |
Second-line medications | |||
Hydralazine (direct vasodilator)Hydralazine (direct vasodilator) | Bolus: 0.1–0.2 mg/kg up to 0.4 mg/kg per dose IV every 4 to 6 hours, maximum dose 20 mg (may be given IM but has an even slower onset of action) | Tachycardia, headache | Hydralazine is given only as a bolus because its longer onset of action time (4 hours) is not as helpful in emergency situations.Hydralazine is given only as a bolus because its longer onset of action time (4 hours) is not as helpful in emergency situations. Response to this medication varies in effect and rate. |
Sodium nitroprusside (direct vasodilator)Sodium nitroprusside (direct vasodilator) | Infusion: Starting 0.3 to 0.5 mcg/kg/minute IV increase every 3 to 5 minutes as needed to a maximum dose of 10 mcg/kg/minute (typical dose 3 to 4 mcg/kg/minute) | Cyanide toxicity with prolonged use (> 72 hours) or in renal failure May increase intracranial pressure | This medication requires careful monitoring and titration. |
Second- or third-line medications | |||
Esmolol (beta-adrenergic blocker)Esmolol (beta-adrenergic blocker) | Infusion: 100–500 mcg/kg/minute IV | May cause profound bradycardia | Esmolol is very short-acting, so constant infusion is needed. Esmolol is very short-acting, so constant infusion is needed. This medication is contraindicated if a pheochromocytoma is possible. |
Enalaprilat (angiotensin-converting enzyme inhibitor) | Infants and children (bolus dosing): 5–10 mcg/kg/dose every 8–24 hours Adolescents and adults (bolus dosing) 0.625–1.25 mg dose every 6 hours | Used in caution with suspected case of renovascular hypertension and acute or chronic kidney disease; contraindicated in pregnancy | Onset of action is in 15 minutes. |
Oral Medications for Children With Asymptomatic Severe Hypertension
Medication (Class) | Dose | Adverse Effects | Comments |
|---|---|---|---|
Clonidine (central alpha-agonist)Clonidine (central alpha-agonist) | For children < 12 years of age, use weight-based dosing: Initial dose 2–5 mcg/kg every 6 to 8 hours adjusted up to 10 mcg/kg; maximum dose may be given up to 4 times a day For children ≥ 12 years of age, use fixed dosing schedule: 0.1 mg 2 times a day increased by 0.1 mg a day as needed up to 0.4 mg 2 times a day | Significant drowsiness, fatigue, dizziness, dry mouth | Clonidine should not be abruptly stopped.Clonidine should not be abruptly stopped. |
Hydralazine (vasodilator)Hydralazine (vasodilator) | Initial dose 0.25 mg/kg every 6 to 8 hours increased as needed up to maximum 25 mg every 6 hours | Tachycardia, headache | Hydralazine has a variable half-life that is genetically determined.Hydralazine has a variable half-life that is genetically determined. Dosage adjustments are needed for children who have renal dysfunction. |
Isradipine (calcium channel blocker)Isradipine (calcium channel blocker) | Initial dose 0.05 to 0.1 mg/kg every 6 to 8 hours up to 5 mg using the immediate-release capsules | Common adverse effects: Flushing, peripheral edema Severe adverse effects: Angioedema | Isradipine causes an exaggerated response in patients taking azole antifungals.Isradipine causes an exaggerated response in patients taking azole antifungals. |
Minoxidil (direct vasodilator)Minoxidil (direct vasodilator) | 0.1 to 0.2 mg/kg once a day up to 10 mg (may increase to every 8 to 12 hours) | Common adverse effects: Dizziness, prolonged hypotension, fluid retention Severe adverse effects: Heart failure, pulmonary edema, Stevens-Johnson syndrome | Minoxidil is the most potent oral vasodilator with a very long length of action and its effects are difficult to reverse.Minoxidil is the most potent oral vasodilator with a very long length of action and its effects are difficult to reverse. Minoxidil is contraindicated in acute myocardial infarction or pheochromocytoma.Minoxidil is contraindicated in acute myocardial infarction or pheochromocytoma. This medication causes significant reflex tachycardia and fluid retention, so may need to use with a beta-blocker and diuretic. Dosage adjustments are needed for children who have renal dysfunction. |
Treatment references
1. National High Blood Pressure Education Program Working Group on High Blood Pressure in Children and Adolescents. The fourth report on the diagnosis, evaluation, and treatment of high blood pressure in children and adolescents. Pediatrics. 2004;114(2 Suppl 4th Report):555-576.
2. Flynn JT, Kaelber DC, Baker-Smith CM, et al. Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents [published correction appears in Pediatrics 2017 Dec;140(6):e20173035. doi: 10.1542/peds.2017-3035] [published correction appears in Pediatrics 2018 Sep;142(3):e20181739. doi: 10.1542/peds.2018-1739]. Pediatrics 2017;140(3):e20171904. doi:10.1542/peds.2017-1904
3. Flynn JT, Tullus K. Severe hypertension in children and adolescents: pathophysiology and treatment [published correction appears in Pediatr Nephrol 2012 Mar;27(3):503-4. Dosage article in article text]. Pediatr Nephrol 2009;24(6):1101-1112. doi:10.1007/s00467-008-1000-1
4. Stein DR, Ferguson MA. Evaluation and treatment of hypertensive crises in children. Integr Blood Press Control 2016;9:49-58. Published 2016 Mar 16. doi:10.2147/IBPC.S50640
Key Points
Hypertensive emergencies involve target organ dysfunction caused by elevated BP.
Admit to intensive care unit and consult a specialist in pediatric hypertension, treat with IV therapy, but do not delay treatment if these assets are not immediately available.
Preferred first-line medications are IV labetalol and nicardipine.Preferred first-line medications are IV labetalol and nicardipine.
Goal of initial therapy is to lower BP to stop target organ damage quickly but not so fast as to cause hypoperfusion.
BP should be lowered by 25% every 8 hours until the 95th percentile is approached and any related symptoms of target organ dysfunction are gone.
An expedited evaluation for the cause and of the hypertensive emergency and potential effects on target on target organs is warranted.
Children who develop a severe hypertensive emergency on top of their chronic hypertension need a more cautious approach to lowering their BP.
