1. Hypertension in children
Antoinette Cilliers
Paediatric Cardiology
Chris Hani Baragwanath Hospital
University of the Witwatersrand
Johannesburg, South Africa

2. Diagnosis in children Bonepart A. Clinical Paediatrics 2009;48:44-49
Underdiagnosis common.
Once elevated Bp is recognized, evaluation and treatment is complex process, requiring multiple visits to confirm the diagnosis, excluding secondary HT, and to assess efficacy of treatment plan.

3. HT definition 4th Report on Diagnosis, Evaluation & Rx, Pediatrics 2004;114:555
Average SBP &/or diastolic BP ≥ 95th percentile for gender, age, and measured ≥ 3 occasions
BP levels ≥ 90th but < 95th centile (or > 120/80 mmHg in adults and adolescents, but < 95th centile) are prehypertensive or at risk of HT.
A patient with BP levels ≥ 95th percentile in doctors office or clinic who is normotensive otherwise has “white-coat hypertension”. Ambulatory BP monitoring is usually required to make the diagnosis.

4. Recommendations for measurement
Oscillometric devices measure
mBP then calculate SBp & DBp.
Variable algorithms & results from device to device.
Useful in newborns & ICUs.
Lurbe E et al. (EUROPEAN GUIDELINES) Hypertension 2009,27: 1719

5. Auscultation
Sphygmomanometer is recommended device. (mercury manometers being out phased because of environmental toxicity, aneroid manometers accurate if calibrated annually)
Stethoscope over brachial artery pulse.
Proximal and medial to the cubital fossa below bottom edge of cuff (i.e. 2 cm above cubital fossa).
Bell of stethoscope allows softer Korotkoff sounds to be heard better.
4th Report on Diagnosis, Evaluation & Rx, Pediatrics 2004;114:555

6. Recommended Dimensions for BP Cuff Bladders
4th Report on Diagnosis, Evaluation & Rx, Pediatrics 2004;114:555

7. Height of arm
Sitting quietly for few minutes before, after avoiding stimulant drugs or foods.
Seated with back supported.
Feet on floor.
Right arm supported, cubital fossa at heart level.
Right arm is preferred in repeated measurements for consistency with standard tables and the possibility of coarctation of the aorta which may lead to falsely low readings in the left arm.
4th Report on Diagnosis, Evaluation & Rx, Pediatrics 2004;114:555

8. Centile BP chart
4th report, 2004
using height
Percentile, boys

9. Centile BP chart
4th report, 2004
using height
Percentile, girls

10. Systolic and diastolic ambulatory BP values for clinical use
Lurbe E et al. J Hypertension 2009,27:1719

11. AGE, yrs
Bps greater than these
values indicate stage 1 &
2 HT, and should be
further evaluated
Kaelber DC et al,
Pediatrics 2009

12. Classification of HT and BP measurement frequency
4th Report on Diagnosis, Evaluation & Rx, Pediatrics 2004;114:555

14. Pathophysiology of HT Stroke Volume Cardiac Output Arterial Pressure
Myocardial
Contractility
Stroke Volume
Cardiac
Output
Size of Vascular
Compartment
Heart
Rate
Arterial Pressure
Vascular
Structure
Peripheral
Resistance
Vascular
Function

15. Importance of HT Raj M, Ind J End & Met 2011;15:S367
HT is a major contributor to the global burden of disease.
Worldwide, 7.6 million premature deaths were attributed to high BP in 2001.
Approximately half of stroke and ischaemic heart disease events worldwide were attributable to high BP during the same period.
Suboptimal BP was reported to account for 10% of global health expenditure in 2001 for population aged 30yrs or more.

16. Essential Hypertension Mild or stage 1 HT (95th-99th centile plus 5mmHg) Most common form of HT in adults and is recognized more often in adolescents than in younger children. Children and adolescents with BP > 90th centile have approximately 3x fold greater likelihood of becoming adults with HT than their peers with BP of 50th centile

17. Essential HT Multifactorial Aetiology Raj M, Ind J of End & Met 2011
Obesity, associated with all of below.
Insulin resistance: increases sympathetic nervous system (SNS)activity.
Activation of the SNS due to hyperinsulinaemia, leptin (adipose derived hormone proportional to amount of white adipose tissue), adiponectin or other adipokines.
Sodium Homeostasis: impaired urinary excretion, salt sensitivity (51% hypertensives, 26% normotensives).
Vascular s.m. structure and reactivity: impaired-flow mediated arterial dilatation, endothelial dysfunction
Serum uric acid levels: affect s.m. reactivity
Genetic Factors: genes encoding Renin-Angiotensin System (RAS), salt sensitivity etc. (family history)
Fetal Programming: SGA babies
Inflammation: HT is a proinflammatory condition especially in obese patients, CRP levels related to increased intimal media thickeness and LVH.

18. Small for gestational age Foetal Programming
Infants born with SGA or IUGR;
- Are at increased risk for insulin resistance because the foetus responds to inadequate in-utero nutrition by diverting nutrients away from skeletal muscle and core organs to preserve brain growth and survival.
- Subsequently this prenatal metabolic reprogramming may result in insulin resistance and obesity.

20. Obesity & essential HT
HT found in 30% of overweight children (BMI > 95th centile)
Overweight + HT are components of Insulin-resistance syndrome or METABOLIC SYNDROME (in 30% overweight children)

21. Metabolic Syndrome 2007 International Diabetes Federation definition of metabolic syndrome in children (10-16yrs) Nathan BM 2008
Truncal
Obesity

22. SALT Daily Salt Requirements: 1 to 1.5g for 1-3yrs (actual intake 2g)
1.2 to 1.9g for 4-8 yrs (2.7g)
1.5 to 2.3 g for 9-50yrs (3.3g)
Food Salt Content:
4 slices of bread = 2g salt
Hamburger = 2.3 g
High content in soup powders, margerine
& seasoning
Low salt food contains < 120mg/100g
Na+ and hypertension
Poor handling of Na+ by kidneys, defect in
Na+ excretion
Excessive responsiveness of vascular tone
Raj M, Ind J End & Met 2011

23. Secondary Hypertension MORE COMMON IN CHILDREN THAN ADULTS most commonly renal or renovascular causes

25. Cardiovascular Examination
Pulse and BP measurements in both arms and legs.
Bruits/murmurs – heart, abdomen, flanks, back, neck.
Signs of left ventricular hypertrophy or cardiac failure.

26. RENAL parenchymal Commonest cause of HT in children
Glomerulopnephritis
Haemolytic Uremic Syndrome

27. External features of syndromes/ conditions associated with HT

28. Systemic Lupus Erythematosis
RASHES
Malar Rash
Systemic Lupus Erythematosis
Henoch Schonlein Purpura

29. Turners Syndrome

30. Williams Syndrome
Supra-aortic stenosis
Renal artery stenosis

31. Neurofibromatosis Leisch Nodules Cafe au Lait spots
Renal artery stenosis

32. Endocrine
Truncal Obesity

33. Ambiguous genitalia Congenital Adrenal Hyperplasia
21-OH deficiency commonest, virulization (androgen excess)
11β-OH less common, HT (mineralocorticoid excess), virulization

34. Takayasu’s Arteritis - Absent arm, neck leg pulses
- Bruits over neck and kidneys

35. Congenital coarctation of the aorta
3-sign and rib notching
- Measure both arms and a leg.
- If leg pulses are weak or absent, coarctation of the aorta may be present

36. Abdominal masses
Polycystic Kidneys
Hydronephrosis
Wilms Tumour

37. α - Adrenergic Receptor Blocker
Phaeochromocytoma
Sweating
Fluctuating blood pressure
α - Adrenergic Receptor Blocker
Cardura = Doxazosin

38. Target Organ Abnormalities

39. Investigations for Hypertension
ROUTINE TESTS
Investigations for Hypertension
SOPHISTICATED
ADDITIONAL RECOMMENDED
Lurbe 2009

40. Management
Lurbe E et al. J Hypertension 2009,27:1719

41. Lifestyle Changes

42. Recommended Lifestyle Changes
Lurbe 2009

43. Treatment Targets Lurbe 2009

44. When to initiate treatment Persistent HT despite non-pharmacological measures also needs Rx
Lurbe E et al. Journal of HT 2009;27:1719
European Society of HT recommendations

45. Monotherapy is first choice
Start with single drug at low dose initially to avoid rapid fall in Bp.
If BP does not decrease within 4-8 weeks, increase to full dose.
If poor response or side effects change to another drug of different class.
If the response is insufficient with one drug, particularly with single-drug treatment, combination therapy may be necessary.
Lurbe E et al. J Hypertension 2009,27:1719

46. Choice of therapy Lurbe 2009
Like in adults, choice of antihypertensive agents include ACE inhibitors, Ca++ antagonists, B-blockers & diuretics.
No head-to head study directly comparing efficacy and safety of different antihypertensive drugs in children and adolescents.

47. RENIN-ANGIOTENSIN-ALDOSTERONE MODULATION OF CARDIAC FAILUREX
ACE I
Vasodilatation
Ventricular remodeling
Preventing hypertrophy + apoptosis
AT – receptor
Blocker (ARB) e.g.
Losartan
Angiotensin II X
AT1 receptor
AT2 receptor
- Vasoconstriction +
sympathetic activation
- Cell proliferation +
hypertrophy/fibrosis
- Aldosterone release
-Vasodilatation
- Inhibition of cell growth
- Apoptosis X
SPIRONOLACTONE inhibits aldosterone

48. Clinical conditions for which specific antihypertensive drug classes are recommenced or contraindicated
Lurbe 2009

49. Recommended initial doses
Norvasc
Adalat
Lurbe 2009

50. Hypertensive Emergency
Defined as severe HT complicated by acute organ dysfunction mainly neurological, renal or cardiac).
Hypertensive Urgency = severe HT without acute organ dysfunction (can be treated with oral therapy).
Bp should not be lowered by more than 25-30% over the first 6-8 hours followed by gradual reduction over the next hours.
Continuous infusion is preferable within ICU setting.
Sodium nitroprusside and labetalol are most often used.
Lurbe 2009

51. Drugs for hypertensive emergencies and urgencies
Lurbe 2009
For Hypertensive Urgencies
Adalat (Nifedipine) given sublingually

52. Resistant Hypertension, causes Lurbe 2009

53. Secondary causes of HT Lurbe 2009
Inversely related to age and directly related to degree of Bp elevation.
Renal parenchymal, renovascular, and coarctation account for 70% -90% all cases (neonates, children, adolescents)
HT seen in 2% term/preterm infants in ICUs, due to umbilical artery catheter-associated thromboembolism affecting the aorta and/or renal arteries and the above.

54. Neonatal Hypertension 95th Centile: systolic BP 65mmHg at 24 w and 90mmHg at 40 weeks postconception
Arterial line - thrombi
Renal Vein thrombosis

56. BP values for Premature Infants
Flynn JT, Pediatr Nephrol 2000;14:332

57. Neonatal HT, Causes Flynn, 2000
Hypoxia ?

58. ORAL medications useful in infants
Flynn, 2000

59. END

60. Intravenous medications for Neonatal Hypertensive Emergencies/Urgencies
Flynn, 2000