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Neonatal Hypertension Workup

  • Author: Joseph Flynn, MD, MS; Chief Editor: Ted Rosenkrantz, MD  more...
 
Updated: Jan 03, 2016
 

Approach Considerations

Usually only a limited set of laboratory data are needed in the evaluation of neonatal hypertension. Obtain serum electrolyte, calcium, creatinine, and blood urea nitrogen (BUN) analysis, as well as urinalysis, in looking for renal parenchymal disease. Obtain endocrinologic studies, such as cortisol, aldosterone, or thyroxine, when pertinent history is noted.

Blood pressure measurement

Proper identification of hypertension in the newborn requires accurate blood pressure (BP) measurement. Fortunately, in most acutely ill infants, BP is usually monitored directly via an indwelling arterial catheter, either in the radial or umbilical artery. This method provides the most accurate BP readings and is clearly preferable to other methods.

In infants who do not have indwelling umbilical lines, automated oscillometric devices are an acceptable alternative method of BP measurement. Although BP readings obtained using such devices may differ slightly from intra-arterial readings, they are easy to use and facilitate the monitoring of BP trends over time. BP readings obtained using such devices are also useful for infants who require BP monitoring after discharge from the NICU. Repeat determinations are advised due to the tendency of oscillometric devices to inflate to a preset value on the first reading.

Pay attention to the size of the cuff and also to the extremity used. Most normative BP data, not only in infants but also in older children, have been collected using BP measurements obtained in the right arm. Because BP measurements obtained in the leg may be slightly higher than those obtained in the arm, the use of other extremities for routine BP determination may complicate the evaluation of hypertension. The nursing staff should document the extremity used for BP determinations and try to use the same extremity for all BP measurements, especially in infants who require antihypertensive treatment.[15]

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Plasma Renin Activity

Measurement of plasma renin activity (PRA) is usually recommended as part of the laboratory assessment in newborns with hypertension, although elevated peripheral renin levels may not signify the presence of underlying pathology, because renin values are typically high in infancy. In addition, plasma renin levels may be falsely elevated by medications that are commonly used in the NICU, such as aminophylline. Keep these factors in mind when interpreting renin values.

Alternatively, suppressed PRA in an infant with hypertension is a significant finding, possibly indicating the presence of a genetic form of hypertension associated with volume overload, such as glucocorticoid-remediable aldosteronism or Liddle Syndrome.

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Imaging Studies

Chest radiography may be helpful in infants with congestive heart failure (CHF) or in those with a murmur upon physical examination.

Perform renal ultrasonography with Doppler of the renal vessels in all hypertensive infants. Accurate renal ultrasonography may help to uncover potentially correctable causes of hypertension (eg, renal venous thrombosis [RVT]), it may detect aortic thrombi and/or renal arterial thrombi, and it may reveal anatomic renal abnormalities or other congenital renal parenchymal disease. Ultrasonography is fast, noninvasive, and relatively inexpensive. The modality has largely replaced intravenous pyelography, which has little, if any, use in the routine assessment of neonatal hypertension.

For infants with extremely severe blood pressure (BP) elevation, angiography may be necessary. Although some investigators have used aortography via the umbilical artery catheter, formal renal arteriography using the traditional femoral vascular approach is much more accurate for diagnosing renal arterial stenosis, primarily because of the high incidence of intrarenal branch vessel abnormalities observed in children with fibromuscular dysplasia. Depending on the expertise available, this may need to be deferred until the infant is larger. Magnetic resonance (MR) and computed tomography (CT) angiography are of little value in infants, as they do not provide sufficient resolution to identify branch vessel stenoses.

Nuclear scanning may demonstrate abnormalities of renal perfusion caused by thromboembolic phenomenon, although obtaining good studies in infants is difficult because of their immature renal function. Obtain other studies, including echocardiography and voiding cystourethrography, as indicated.

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Contributor Information and Disclosures
Author

Joseph Flynn, MD, MS Chief, Division of Nephrology, Seattle Children's Hospital; Professor, Department of Pediatrics, University of Washington School of Medicine

Joseph Flynn, MD, MS is a member of the following medical societies: American Academy of Pediatrics, American Heart Association, American Society of Hypertension, American Society of Nephrology, American Society of Pediatric Nephrology, National Kidney Foundation, Phi Beta Kappa

Disclosure: Received consulting fee from Pfizer, Inc for review panel membership; Received royalty from UpToDate, Inc. for author; Received royalty from Spronger, Inc for authoring.

Chief Editor

Ted Rosenkrantz, MD Professor, Departments of Pediatrics and Obstetrics/Gynecology, Division of Neonatal-Perinatal Medicine, University of Connecticut School of Medicine

Ted Rosenkrantz, MD is a member of the following medical societies: American Academy of Pediatrics, American Pediatric Society, Eastern Society for Pediatric Research, American Medical Association, Connecticut State Medical Society, Society for Pediatric Research

Disclosure: Nothing to disclose.

Acknowledgements

Arun K Pramanik, MD, MBBS Professor of Pediatrics, Director of Neonatal Fellowship, Louisiana State University Health Sciences Center

Arun K Pramanik, MD, MBBS is a member of the following medical societies: American Academy of Pediatrics, American Thoracic Society, National Perinatal Association, and Southern Society for Pediatric Research

Disclosure: Nothing to disclose.

Mary L Windle, PharmD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy, Pharmacy Editor, eMedicine

Disclosure: Nothing to disclose.

References
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  2. Friedman AL, Hustead VA. Hypertension in babies following discharge from a neonatal intensive care unit. A 3-year follow-up. Pediatr Nephrol. 1987 Jan. 1(1):30-4. [Medline].

  3. Blowey DL, Duda PJ, Stokes P, Hall M. Incidence and treatment of hypertension in the neonatal intensive care unit. J Am Soc Hypertens. 2011 Sep 17. [Medline].

  4. Neal WA, Reynolds JW, Jarvis CW, Williams HJ. Umbilical artery catheterization: demonstration of arterial thrombosis by aortography. Pediatrics. 1972 Jul. 50(1):6-13. [Medline].

  5. Abman SH, Warady BA, Lum GM, Koops BL. Systemic hypertension in infants with bronchopulmonary dysplasia. J Pediatr. 1984 Jun. 104(6):928-31. [Medline].

  6. Alagappan A, Malloy MH. Systemic hypertension in very low-birth weight infants with bronchopulmonary dysplasia: incidence and risk factors. Am J Perinatol. 1998 Jan. 15(1):3-8. [Medline].

  7. Sahu R, Pannu H, Yu R, Shete S, Bricker JT, Gupta-Malhotra M. Systemic hypertension requiring treatment in the neonatal intensive care unit. J Pediatr. 2013 Jul. 163(1):84-8. [Medline].

  8. Seliem WA, Falk MC, Shadbolt B, Kent AL. Antenatal and postnatal risk factors for neonatal hypertension and infant follow-up. Pediatr Nephrol. 2007 Dec. 22(12):2081-7. [Medline].

  9. Zubrow AB, Hulman S, Kushner H, Falkner B. Determinants of blood pressure in infants admitted to neonatal intensive care units: a prospective multicenter study. Philadelphia Neonatal Blood Pressure Study Group. J Perinatol. 1995 Nov-Dec. 15(6):470-9. [Medline].

  10. Pejovic B, Peco-Antic A, Marinkovic-Eric J. Blood pressure in non-critically ill preterm and full-term neonates. Pediatr Nephrol. 2007 Feb. 22(2):249-57. [Medline].

  11. Kent AL, Kecskes Z, Shadbolt B, Falk MC. Normative blood pressure data in the early neonatal period. Pediatr Nephrol. 2007 Sep. 22(9):1335-41. [Medline].

  12. Dionne JM, Abitbol CL, Flynn JT. Hypertension in infancy: diagnosis, management and outcome. Pediatr Nephrol. 2012 Jan. 27(1):17-32. [Medline].

  13. Dionne JM, Abitbol CL, Flynn JT. Erratum to: Hypertension in infancy: diagnosis, management and outcome. Pediatr Nephrol. 2012 Jan. 27(1):159-60. [Medline].

  14. Task Force on Blood Pressure Control in Children. Report of the Second Task Force on Blood Pressure Control in Children--1987. Task Force on Blood Pressure Control in Children. National Heart, Lung, and Blood Institute, Bethesda, Maryland. Pediatrics. 1987 Jan. 79(1):1-25. [Medline].

  15. Crossland DS, Furness JC, Abu-Harb M, et al. Variability of four limb blood pressure in normal neonates. Arch Dis Child Fetal Neonatal Ed. 2004 Jul. 89(4):F325-7. [Medline].

  16. Brierley J, Marks SD. Treating the causes of paediatric hypertension using non-invasive physiological parameters. Med Hypotheses. 2010 May 3. [Medline].

  17. Batisky DL. Neonatal hypertension. Clin Perinatol. 2014 Sep. 41(3):529-42. [Medline].

  18. Nickavar A, Assadi F. Managing hypertension in the newborn infants. Int J Prev Med. 2014 Mar. 5(Suppl 1):S39-43. [Medline].

 
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Normal blood pressure percentile curves for older infants. From the Second (1987) Task Force on Blood Pressure Control in Childhood; National Heart, Lung, and Blood Institute.
Table 1. Neonatal Blood Pressures and Potential Treatment Parameters. Adapted from Dionne et al.*
Postconceptual Age 50th Percentile 95th Percentile 99th Percentile
44 weeks      
SBP 88 105 110
DBP 50 68 73
MAP 63 80 85
42 weeks      
SBP 85 98 102
DBP 50 65 70
MAP 62 76 81
40 weeks      
SBP 80 95 100
DBP 50 65 70
MAP 60 75 80
38 weeks      
SBP 77 92 97
DBP 50 65 70
MAP 59 74 79
36 weeks      
SBP 72 87 92
DBP 50 65 70
MAP 57 72 77
34 weeks      
SBP 70 85 90
DBP 40 55 60
MAP 50 65 70
32 weeks      
SBP 68 83 88
DBP 40 55 60
MAP 49 64 69
30 weeks      
SBP 65 80 85
DBP 40 55 60
MAP 48 63 68
28 weeks      
SBP 60 75 80
DBP 38 50 54
MAP 45 58 63
26 weeks      
SBP 55 72 77
DBP 30 50 56
MAP 38 57 63
Table 2. Intravenous Drugs for Severe Hypertension in Neonates [12]
Drug Class Intravenous (IV) Dosage Comments
Esmolol Beta blocker 100-300 mcg/kg/min IV infusion Very short acting; constant IV infusion necessary
Hydralazine Vasodilator (arteriolar) 0.15-0.6 mg/kg/dose IV bolus or 0.75-5mcg/kg/min IV constant infusion Tachycardia is frequent adverse effect; must administer every 4 hours when administered as IV bolus
Labetalol Alpha blocker and beta blocker 0.2-1 mg/kg/dose IV bolus or 0.25-3 mg/kg/h IV constant infusion Heart failure, bronchopulmonary dysplasia (BPD), relative contraindications
Nicardipine Calcium channel blocker 1-5 mcg/kg/min IV constant infusion May cause reflex tachycardia
Sodium nitroprusside Vasodilator (arteriolar and venous) 0.5-10 mcg/kg/min IV constant infusion Thiocyanate toxicity can occur with prolonged use (>72 h) or in renal failure; usual maintenance dose is below 2 mcg/kg/min; may use 10 mcg/kg/min for short duration (ie, < 10-15 min)
Table 3. Oral Antihypertensive Agents Useful for Treatment of Neonatal Hypertension [12]
Drug Class Oral Dosage Comments
Captopril Angiotensin-converting enzyme (ACE) inhibitor Under age 3 months: 0.01-0.5 mg/kg/dose 3 times daily; not to exceed 2 mg/kg/day



At or above age 3 months: 0.15-0.3 mg/kg/dose 3 times daily; not to exceed 6 mg/kg/day



Monitor serum creatinine and potassium levels
Clonidine Central agonist 0.05-0.1 mg/dose 2-3 times daily Adverse effects include dry mouth and sedation; rebound hypertension with abrupt discontinuation
Enalapril ACE inhibitor 0.08-0.6 mg/kg/day, given once or twice daily Monitor serum creatinine and potassium levels
Hydralazine Vasodilator (arteriolar) 0.25-1 mg/kg/dose 3-4 times daily; not to exceed 7.5 mg/kg/day Suspension stable up to 1 wk; tachycardia and fluid retention are common adverse effects; lupuslike syndrome may develop in slow acetylators
Isradipine Calcium channel blocker 0.05-0.15 mg/kg/dose 4 times daily; not to exceed 0.8 mg/kg/d or 20 mg/day Suspension may be compounded; useful for both acute and chronic hypertension
Amlodipine Calcium channel blocker 0.1-0.3 mg/kg/dose twice daily; not to exceed 0.6 mg/kg/d or 20 mg/d Less likely to cause sudden hypotension than isradipine
Minoxidil Vasodilator (arteriolar) 0.1-0.2 mg/kg/dose 2-3 times daily Most potent oral vasodilator; excellent for refractory hypertension
Propranolol Beta-blocker 0.5-1 mg/kg/dose 3 times daily Maximal dose depends on heart rate; may administer as much as 8-10 mg/kg/d if no bradycardia; avoid in infants with BPD
Labetalol Alpha and beta blocker 1 mg/kg/dose 2-3 times daily, up to 12 mg/kg/d Monitor heart rate; avoid in infants with BPD
Spironolactone Aldosterone antagonist 0.5-1.5 mg/kg/dose twice daily Potassium-sparing diuretic; monitor electrolytes; several days necessary to observe maximum effectiveness
Hydrochlorothiazide Thiazide diuretic 2-3 mg/kg/d orally every day or divided twice daily Monitor electrolytes
Chlorothiazide Thiazide diuretic 5-15 mg/kg/dose twice daily Monitor electrolytes
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