Monday, February 22, 2010

Definition of Hypertension in Youth

Assessment and Management of Hypertension in Children and Adolescents

The Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents[12] provides systolic and diastolic blood pressure levels corresponding to the 50th, 90th, 95th, and 99th percentiles based on the child's sex, age, and height percentile.
The height percentile is plotted from normal growth charts. The blood pressure tables and instructions for using them are available in the report[12] and online.[14]

Blood pressure status can be classified on the basis of systolic and diastolic blood pressure percentiles ( Table 1 ).
Measurements below the 90th percentile are considered normal.
Prehypertension or hypertension are present when measurements of either systolic or diastolic pressure, or both, are at or above the 90th percentile.
Blood pressure should be measured at least twice during the same assessment, and confirmed over at least three separate occasions.

Prehypertension is present when the measurement is at or above the 90th percentile, but less than the 95th percentile, as well as when blood pressure reaches or exceeds 120/80 mmHg in an adolescent.
Hypertension is present when repeated measurements are at or above the 95th percentile.
Hypertension is further classified as either stage 1, in which blood pressure ranges from the 95th to the 99th percentile plus 5 mmHg, or stage 2, where blood pressure is above the 99th percentile plus 5 mmHg.

'White coat' hypertension occurs when the patient's blood pressure remains above the 95th percentile when measured in a clinical setting, but is normal when measured in a familiar setting.
If hypertension is confirmed, blood pressure should be measured in both arms and a leg.
The classification of blood pressure influences decisions on evaluation and management.

Table 1. Classification of Hypertension in Youth*
Category Systolic or diastolic blood pressure percentile
Normal < 90th
Prehypertension 90-95th, or if blood pressure exceeds 120/80 mmHg even if < 90th up to < 95th
Stage 1 hypertension 95-99th plus 5 mmHg
Stage 2 hypertension >99th plus 5 mmHg
*Percentiles are based on normative values related to sex, age, and height percentile. If systolic and diastolic categories are different, classify by the higher category.

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