Pocket Pediatrics: The Massachusetts General Hospital for Children Handbook of Pediatrics (Pocket Notebook Series), 2 Ed.

ESSENTIAL HYPERTENSION

Definition

• Essential HTN is BP >95th percentile (sex, age, and height specific) in the absence of other etiologies (Pediatr Rev 2007;28:283) Per published BP charts. (Pediatrics 2004;114:555)

• Pre-HTN: Avg SBP and/or DBP ≥90th but ≤95th percentile or adol ≥120/80

• Stage I HTN: Avg SBP and/or DBP ≥95th percentile

• Stage II HTN: Avg SBP and/or DBP 5 mm Hg >95th percentile

• HTN urgency/emergency: Avg SBP and/or DBP 5 mm Hg >95th percentile w/ clinical signs or sx (chest pain, HA, epistaxis, lethargy, seizure, encephalopathy, diplopia)

• ∼2–5% of children have essential hypertension but only 23% carry the dx (even w/ elevated BPs × 3 documented by PCP) (JAMA 2007;298:874)

• BP should be checked at R arm w/ cuff width ∼40% or arm circ at midpoint humerus

• Measured after seated for 5 min in controlled environment w/ R arm at heart level

• Cuff too large underestimates BP, cuff too small overestimates BP

Epidemiology (Am Fam Physician 2006;73:1558)

• Familial patterns of essential HTN well established; heritability estimated at 50%

• BMI has been demonstrated to be a strong risk factor for development of HTN

• Insuff data to define role of ethnicity; some studies show AA > Caucasian children

• Obesity: Defined as >95 percentile for age and sex; 3–5× inc risk of HTN

• 30% of obese pediatric patients have hypertension (Pediatrics 2004;114:555)

• Essential HTN linked w/ risk factors of metabolic syndrome (low HDL, inc trigs, abd obesity, insulin resistance/hyperinsulinemia); prevalence 4.2–8.4% in adolescents

Etiology (Pediatr Rev 2007;28:283)

• Most childhood HTN due to 2° causes (60–70% renal dz, rarely essential HTN <10 yo); adolesc HTN 85–90% essential HTN

• Initial eval should assess 2° causes but more strongly suggested in younger children, those w/ stage II HTN and w/ other systemic symptoms (Pediatrics 2004;114:555)

• Renal: Renal artery stenosis (abd bruit), polycystic kidney dz, parenchymal dz, Wilms tumor, neuroblastoma

• Obstructive sleep apnea (OSA): Affects 1–3% of children, assoc w/ inc DBP

• Drugs—albuterol, amphetamines, antidepressants, antipsychotics, caffeine, cocaine, EtOH, NSAIDs, OCPs, OTC allergy/cold meds, and steroids

• Endocrine: Pheochromocytoma (w/ flushing and diaphoresis), Cushing (moon facies, hirsutism, acne, obesity), hyperthyroidism (thyromegaly, tachy, weight loss), hyperaldosteronism (muscle weakness)

• Neonatal Hx: Umbilical artery catheter, asphyxia, BDP, maternal substance use, unequal peripheral pulses (aortic coarctation)

• Systemic lupus erythematosus and other CTD (joint pain, malar rash)

Evaluation (Pediatr Rev 2007;28:283; Pediatrics 2004;114:555)

• BP checks start at 3 yo at regular checkups (Pediatrics 2004;114:555)

• Initial focused history for FHx, medication Hx, and possible 2° causes as above

• Exam w/ BMI, 4 ext BPs, retinal exam for chronicity (presence of copper wiring and AV knicking), cardiovascular exam for extra heart sounds, murmurs, and bruits

• Moon facies, truncal obesity, violaceous striae in Cushing syndrome

• Webbed neck and wide-spaced nipples in Turner syndrome

• Abd mass/palpable kidney in Wilms tumor, neuroblastoma, pheochromocytoma, polycystic kidney disease, hydronephrosis

• Malar rash, friction rub, & joint swelling & pains in SLE or other CTD

• Lab testing and imaging to assess end organs and identify possible etiologies

• CBC w/ diff (anemia 2/2 CKD), electrolytes w/ BUN/Cr and Ca++, Phos, Mg++ (assess renal dz, calculi dz), U/A (assess for infection, hematuria, proteinuria), 24-hr urine protein and creatinine (to calculate CrCl)

• Imaging: Renal U/S w/ Doppler (assess renal scarring, cong anom, unequal size), may need further imaging assess renovasc dz (CTA, MRA, arteriography)

• Studies assessing end organs; echo (presence of LVH), retinal exam, and renal U/S

• Hormonal studies: Plasma rennin (mineralocorticoid dz), thyroid, adrenal, urine, and plasma catecholamines (pheo)

• ↑ serum uric acid assoc w/ HTN; >5.5 mg/dL in 89% pts w/ essent HTN; 30% w/ 2° HTN

Treatment (Pediatrics 2004;114:555)

• Lifestyle modification 1st line for all pts w/ HTN (weight reduction if overweight, regular physical act, dietary mod, all more successful when family based)

• Indication for drugs; inadeq resp to lifestyle mod or 2° HTN (goal to ↓BP <95th %ile)

• First-line therapy ACE-I, ARBs, BB, CCBs, and diuretics

• Can tailor Rx to underlying dz (i.e., ACE-I or ARB w/ DM or proteinuria)

• Regular monitoring for drug toxicity and for end organ BP damage necessary

• Patient’s HTN emergency must be managed w/ IV antihypertensives w/ goal to dec BP by <25% in the 1st 8 hr and normalized BP over next 24–48 hr