Hypertensive Urgency/Emergencies
Contributing Author: Natalie Hecht, NP
Definition
Hypertension: systolic BP and/or diastolic BP >95th percentile (based on gender, age and height) on at least 3 readings
Hypertensive urgency: severe increase in BP without signs of organ damage; may present with mild symptoms, such as headaches and/or nausea
Hypertensive emergency: severe increase in BP accompanied by life-threatening symptoms and/or acute organ damage
* Degree of hypertension is less important than signs of end organ damage
NIH Blood Pressure Tables for Children and Adolescents: http://www.nhlbi.nih.gov/health-pro/guidelines/current/hypertension-pediatric-jnc-4/blood-pressure-tables
Diagnosis
Measurement
Arterial line BP is most accurate
If noninvasive, blood pressure is most reliably measured in right upper extremity (ensure proper cuff size: cuff too small leads to falsely elevated BP)
Signs of end organ damage
Brain: encephalopathy is most common manifestation of hypertensive emergency
Severe nausea/vomiting, headache, vision changes
Mental status changes: confusion, lethargy, coma
Cerebral edema
Seizures
Stroke
Eyes
Decrease in peripheral vision
Papilledema, retinal hemorrhage /retinopathy
Kidneys
Acute renal failure
Elevated creatinine
Hematuria and proteinuria (though this is usually a manifestation of glomerulonephritis as the cause of HTN)
Heart
Left ventricular heart failure due to sudden increase in afterload
Pulmonary edema
Myocardial ischemia
Aortic dissection, especially in patients with predisposition (Marfan)
On exam: diffuse fine crackles, S3 gallop
Etiology
Renal: most common etiology of hypertension in pediatric patients
Renal artery stenosis
PSGN
HUS
Neuro
Acute stroke (may be cause of HTN or reflex response to maintain CPP)
Pseudotumor cerebri
Cardiac
Aortic dissection (accompanying sx include chest or abd pain)
Coarctation
Endocrine
Thyroid crisis
Cushing syndrome
Pheochromocytoma
Ingestions/drugs
PCP, cocaine, amphetamines
Immunosuppressive therapy (ie tacrolimus or cyclosporine) or erythropoietin use
Workup and Management
Work Up
Electrolytes, CBC, UA
EKG, CXR, ECHO
4 limb BPs
Fundoscopic exam to assess papilledema, retinal hemorrhage
Detailed neuro exam: meningeal irritation, visual fields
Kidney US
Drug screen
History of Marfan syndrome
Pregnancy test to rule out preeclampsia (positive pregnancy may also impact meds used)
Management
Goal: decrease BP by 20-25% of overall goal (usually, goal is 95th-99th percentile of BP for age, gender and height). Gradually normalize BP over 24-48 hours. Dropping the BP rapidly may worsen end-organ damage.
Medications: Generally safest to begin with continuous infusion, which can be titrated or held based on response
First line
Clevidipine: Calcium Channel Blocker (dihydropyridine), smooth muscle relaxation and vasodilation
0.5-1 mcg/kg/min initially, titrated by increments of 0.5-1 mcg/kg/min (max 10 mcg/kg/min). (Tobias JD et al, 2011) Adult dosing 1-2 mg/hr up to max of 21 mg/hr.
Comes in oil-in-water emulsion containing 200 mg/ml (2 kcal/mL) of lipid
Onset of action 2-4 minutes with duration 5 to 15 minutes.
Metabolized by rapid hydrolysis in bloo and extravascular tissue by esterases. Half-life elimination 1 minutes (terminal 15 minutes)
Nitroprusside: Breaks down to release NO, nonselective vasodilator, decreases both systemic and pulmonary resistance
0.3-0.5mcg/kg/min initial dose to max of 5mcg/kg/min
Rapid onset with peak hypotensive effect within 2 minutes
Cyanide poisoning, leading to severe lactic acidosis can occur after hours to days of drip. Methemoglobinemia causing acidosis is another adverse effect.
Nicardipine: CCB, smooth muscle relaxation and vasodilation
Loading dose 5-10mcg/kg, followed by infusion of 0.5-1mcg/kg/min. May increase slowly every 15 minutes to max of 5mcg/kg/min
Onset of action 5-15 min, peak effect 30 min - 2 hrs
Reflex tachycardia may occur
Labetalol: alpha-1 & beta blocker
0.2-1 mg/kg/dose up to 40mg/dose (start at lower range) as an initial bolus dose, then 0.25-3mg/kg/hr
Onset of action 2-5 min, peak effect 5-15 min
Contraindicated in asthmatics, patients with heart failure
Second line
Esmolol: beta-1 agonist
Loading dose of 300-500mcg/kg, then infusion of 25-200mcg/kg/min, which may be increased q5-15min to max of 1,000mcg/kg/min
Peak effect 6-10 min, ultra short acting
Associated with bradycardia
Contraindicated in heart block, cardiogenic shock, asthma / bronchoconstriction
For use in hypertensive urgency only, not emergency:
Isradipine: CCB
0.05-0.1 mg/kg/dose
Onset 1 hour, peak effect 2-3 hours
Nifedipine: CCB
Oral or sublingual administration only
0.25-0.5mg/kg/dose (start low due to risk of precipitous hypotension)
Onset 15-30 min with half life 1.5 hr
May cause reflexive tachycardia
Hydralazine: vasodilator of arterial smooth muscle
Slower onset and longer acting than labetalol & nicardipine
0.2-0.6mg/kg/dose
Onset 30 min - 2 hr, duration 6-12 hr
May be given q4hr
IV or IM
Volume depletion is common in hypertensive crises; consider IV crystalloid if BP is dropping excessively to assist with organ perfusion
From Singh et al, International Journal of Nephrology, 2012
References
1) Helfaer & Nichols, Rogers’ Handbook of Pediatric Intensive Care. 4th Edition, 2009.
2) The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Pediatrics
3) Flynn JT. Management of hypertensive emergencies and urgencies in children. UpToDate. 2015