Hypertensive Emergency

2017 American Academy of Pediatrics updated definitions for pediatric blood pressure categories

Hypertensive Urgency: Stage II hypertension without symptoms or evidence of end-organ damage. In this case, urgent medical intervention is needed to bring down the blood pressure, but it is not considered an emergency situation.

Hypertensive Emergency: Stage II hypertension with signs of end-organ damage (eg: seizures, encephalopathy, AKI, heart failure) that warrants immediate medical intervention to lower the blood pressure and prevent further damage to the organs.

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Causes of Hypertension

• First year of life

  Secondary (99%)

  • Coarctation of aorta

  • Renovascular

  • Renal parenchymal disease

  • Miscellaneous causes (BPD, PDA, IVH)

  • Endocrine (CAH, Hyperaldosteronism, Hyperthyroidism)

  • Neoplasia (Wilm’s tumor, Neuroblastoma, Pheochromocytoma)

• Age 1 - 12 years

  Secondary (70-85%)

  • Coarctation of aorta

  • Renovascular

  • Renal parenchymal disease

  • Reflux nephropathy

  • Endocrine (CAH, Hyperaldosteronism, Hyperthyroidism)

  • Neoplasia (Wilm’s tumor, Neuroblastoma, Pheochromocytoma)

  Primary (Essential) (15-30%)

• Age 12 - 18 years

  Primary (Essential) (85-95%)

  Secondary (5-15%):

  • Coarctation of aorta

  • Renovascular

  • Renal parenchymal disease

  • Reflux nephropathy

  • Endocrine (CAH, Hyperaldosteronism, Hyperthyroidism)

  • Neoplasia (Wilm’s tumor, Neuroblastoma, Pheochromocytoma)

Diagnosis

In general, hypertension workups can be done outpatient after failure of lifestyle modifications and should be tailored based on suspected secondary causes. Workup is indicated in the ED in cases of severe acute hypertension. Some studies to consider include:

• CBC

  Assess for anemia or infection

• CMP

  Assess for AKI and electrolyte abnormalities (hyper/hyponatremia, hyper/hypokalemia, hypercalcemia)

  Screen for hepatic steatosis and transaminitis.

• POC blood glucose, HbA1c

  Screen for diabetes

• UA/UDS

  Assess for hematuria, proteinuria, pyuria, bacteriuria

  If concerned about ingestion, get UDS

• Lipids

  Assess for elevated cholesterol, LDL, TG, low HDL

• Plasma renin activity

  Low or absent renin

• Consider RBUS +/- doppler (esp if <6 yo, abnormal UA, or renal function)

  Renovascular disease (Renal artery stenosis (RAS), fibromuscular dysplasia)

  Mass, vascular malformations, bilateral small kidneys, discrepant kidney sizes (>1.5 cm), bilateral large kidneys, hydronephrosis, renal tubers, congenital anomalies.

  Screening test: if negative then not likely to have RAS

  If positive, get a CTA or MRA to ruleout RAS. Can also get blood tests to show high renin and aldosterone.

• EKG/Echocargiogram

  LVH is a sign of systemic HTN

• Consider neuroimaging

  Papilledema, AMS, seizures, or focal neurologic deficits can indicate increased cranial pressure secondary to an intracranial mass, intracranial hemorrhage, or stroke.
  

Acute Hypertension Management

In general, PRN antihypertensives are indicated when blood pressure is >95th%ile + 12 mmHg for age or >140/90 (stage II HTN)

1. Treat underlying cause. Consider easily reversible causes (pain, fever, anxiety).

2. For hypertensive urgency, start PO isradipine or IV hydralazine

3. For hypertensive emergencies, start IV labetalol bolus with a continuous infusion or nicardipine infusion.

   1. Over 8 hours, lower BP no more than 25% of the difference between the current SBP and the SBP goal.

   2. IV Hydralazine is not suitable as it has a slower onset of action and a longer duration of action which can cause inadvertent hypotension and end-organ ischemia.

4. Consider diuretics if signs of volume overload

• Isradipine PO 0.05 to 0.1 mg/kg/dose (max 5 mg)

  Onset: 30 minutes

  Duration: 2 to 8 hours

  Can cause peripheral edema, headache, dizziness, flushing, palpitations, dyspnea

• Clonidine PO 2 to 5 mcg/kg (max 10 mcg/kg) q6-8h

  Onset: 15 to 30 minutes

  Duration: 6 to 8 hours

  Can cause somnolence, headache, abdominal pain, fatigue, nightmares, and irritability

• Hydralazine IV 0.1-0.4 mg/kg (max 20 mg) q4-6h

  Onset: 10 minutes (max effect may take up to 80 minutes)

  Duration: 4 to 6 hours

  May cause reflex tachycardia

• Labetalol IV Bolus 0.1-1 mg/kg q4h (max dose 40 mg) | Infusion 0.25-3 mg/kg/h

  Onset: 2 to 5 minutes

  Duration: 2 to 6 hours

  Relatively contraindicated in asthma, BPD, heart failure, and may mask symptoms of hypoglycemia.

• Nicardipine IV Infusion 0.5-4 mcg/kg/min

  Can bolus 30 mcg/kg (max 2 mg/dose)

  Onset: 2 to 5 minutes

  Duration: 30 minutes to 4 hours

  May cause reflex tachycardia