Paediatric Hypertension (HTN)

(This appears in the June 2017 Newsletter, and continued from the April 2017 Newsletter)

Prevalence of HTN in children aged 8-17 years was approximately 2.2% between 2011 and 2014. Compare this with asthma prevalence of 9%, autism 1%, epilepsy 1%, and yet these all get much more air time than hypertension. Up to 30% of newly diagnosed hypertensive children and young people already have end organ damage, left ventricular hypertrophy in particular. [note]Lewis M et al. Screening for Hypertension in Children and Adolescents: Methodology and Current Practice Recommendations. Front Pediatr. 2017; 5: 51 full text. Great Ormond Street Hospital clinical guideline on the diagnosis, investigation and management of hypertension.[/note]

Hypertension: important points in the history:

  • Symptoms: lethargy, visual disturbances, headache, nausea, vomiting, failure to thrive
  • Past medical history: prematurity, central lines, UTIs, congenital heart disease
  • Family history: essential hypertension, polycystic kidneys, early CVS disease

BP measurement in babies and children is a skill which is often not done well:

  • Cuff size – you need a range of sizes. The bladder width needs to be at least 40% of the child’s arm circumference between olecranon and acromion and 80-100% of the circumference. A small cuff leads to an erroneously high BP measurement. Take BP in the arm, not leg (both if doing 4-limb BP obviously). At birth, BP measured in the legs is often lower than in the arms, equalises at 8/52 of age and after that leg blood pressure tends to be higher than in the arm.
  • Position – the child should ideally be lying down, relaxed, their limb at the same level as their heart.
  • Equipment – centile charts are put together using auscultation and a sphygmomanometer. Mechanical oscillometric devices are easy to use (be sure to still ensure correct cuff size) but are not as accurate which is why nephrologists always insist on a “manual reading”.

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