Definitions (Pediatr Rev 2007;28:283; Pediatrics 2004;114(2 Suppl, 4th Report):555; JAMA 2003;289:2560)
• 2° HTN (BP >95th percentile for age and ht) – ↑ BP 2/2 underlying, identifiable cause
• Stage 1 = BP at 95th %ile – 5 mm Hg above 99th %ile; Stage 2 = BP >5 mm Hg above 99th %ile
• Hypertensive urgency = HTN w/o severe sx or evidence of end organ damage
• Hypertensive emergency = HTN w/ severe sx + evidence of end organ damage (in children, retinopathy, encephalopathy—lethargy, coma, sz—more common than CHF, pulmonary edema) (Arch Dis Child 1992;67:1089)
Etiology & Dx (Nat Rev Cardiol 2010;7:155; Pediatr Rev 2007;28:283)
• Evaluation begins with thorough H&P & exam. 75% cases 2/2 renal parenchymal dz
• Hypertensive emergency in children is most likely renal in origin
• Meds (amphetamines, corticosteroids, OCP, cyclosporine, others) can cause HTN
• Renovascular disease (may be assoc w/ high renin levels but not a consistent finding)
• Ultrasonography can show decreased flow; renal arteriography is “gold standard”
• MRA, CTA, and captopril-MAG 3 scanning each have strengths and limitations
• Renal parenchymal disease (evidence of glomerular or tubular dysfxn, dec GFR)
• US shows size, location, echogenicity. Scarring can cause HTN and is a more common cause of 2° hypertension than glomerulonephritis
• Renal scarring occurs 2/2 multiple, often overlapping etiologies; congenital
dysplasia, vesicoureteral reflux, and infxn. Regardless etiology, scarring is
prerequisite to develop HTN as sequelae (J Urol 2005;173:697)
• 5–44% of children with ADPKD have secondary HTN (Lancet 2007;369:1287)
• Steroidogenic enzyme defects (11-β-hydroxylase def, 11-α-hydroxylase def), hyperaldo, apparent mineralocorticoid excess, and nonsteroidal defects (Liddle
syndrome, Gordon syndrome) can be assoc w/ low renin levels
• Cardiovascular disorders (coarctation, midaortic syndrome); 4 extremity blood pressures, differential cyanosis, echocardiography can be diagnostic
• Other: Umbilical artery catheterization, collagen vascular dz, SLE, hyper-/hypothyroid, Williams syndrome (and assoc renal vasc dz), Turner syndrome (and assoc coarctation), Cushing syndrome (and assoc steroid excess), neurofibromatosis (renovasc HTN, pheochromocytoma), lower extremity traction
• Possible assoc exists btw hyperuricemia and HTN (uric acid >5.5 mg/dL found in 89% of children w/ essential HTN but 30% 2° HTN); mechanism unknown
Therapy (Pediatr Nephrol 2009;24:1101; Pediatr Rev 2007;28:283)
• Based on underlying etiology
• Hypertensive urgency – tx w/i hours
• Hypertensive emergency – must continually monitor BP & avoid excessively rapid
reduction (↓ 1/3 of tot reduction in 6 h, 2/3 tot by ∼24 h, to maintenance by ∼48–72 h) using short-acting agents (labetalol, nicardipine most studied, no agents proven in children)
• See Cardiology Chapter and (J Pediatr 2006;149:746) on treatment of hypertension