To recognize hypertension, it is important to measure blood pressure correctly. The National High Blood Pressure Education Program recommends auscultation as the standard approach. However, concerns about mercury toxicity have led some hospitals and clinics to remove mercury column sphygmomanometers and institute use of automated devices. Most automated devices use oscillometric methodology. It is important to review data on validation and reliability before accepting a device for use. Another alternative for blood pressure measurement is to use an aneroid device. However, these devices must be periodically calibrated against a mercury column.

No matter which equipment is used, the selection of an appropriately sized cuff is one of the most important aspects of blood pressure measurement. The recommended approach is to use a cuff with a bladder width that is approximately 40% of the upper arm circumference between the acromion and the olecranon. The length of the cuff bladder should include 80% to 100% of the arm circumference. Manufacturers of cuffs usually have lines on the cuff that indicate the range of arm sizes for which that cuff bladder will be appropriate.

Blood pressure should usually be measured in the right arm with the patient in the sitting position after a period of 3 to 5 minutes of rest. The arm in which the blood pressure is measured should be resting at heart level on a solid surface. The cuff should be inflated approximately 20 mm Hg above the
point at which the radial pulse disappears. The cuff is deflated at a rate of 2 to 3 mm Hg per second. The first Korotkoff phase (appearance of snapping tones) is used to indicate systolic pressure, and the fifth Korotkoff phase (disappearance of sound) is used to determine the diastolic blood pressure.

In adults, blood pressure standards are based on the relationship to outcomes. In adolescents, there are no outcome-based standards. Instead, a “distributational” approach is used. In this classification approach, blood pressure percentiles based on the patient’s age, sex, and height are used. Blood pressure lower than the ninetieth percentile is considered normal. Systolic or diastolic blood pressure between the ninetieth and ninety-fifth percentiles is considered to be prehypertension. As with adults, adolescents with blood pressure 120/80 mm Hg or higher should also be considered prehypertensive. Blood pressure above the ninety-fifth percentile that remains above the ninety-fifth percentile on three separate occasions is considered to be in the hypertensive range. Those in the hypertensive range should be classified as having either stage 1 or stage 2 hypertension. These cutpoints are presented in Table 93.1. Stage 2 hypertension is when the blood pressure is higher than 5 mm Hg above the ninety-ninth percentile. Stage 2 hypertension often requires immediate evaluation and treatment. The blood pressure percentiles recommended by the National High Blood Pressure Education Program are present in Tables 93.2 and 93.3.

Adolescents with suspected hypertension should have a complete history and physical examination. The history and examination may yield clues to whether a secondary form of hypertension is present. For example, a history of abdominal pain, dysuria, frequency, nocturia, and enuresis may suggest the presence of underlying renal disease. The absence of femoral pulses may indicate coarctation of the aorta.

Primary hypertension is rarely accompanied by abnormalities in the history of present illness or the physical examination. Symptoms such as headache, visual disturbance, chest pain, and epistaxis are often attributed to blood pressure elevation, but in fact these features are rarely associated with mild to moderate blood pressure elevation. Adolescent patients with primary hypertension often have a positive family history of hypertension and are more likely to be overweight.

The standard approach to laboratory testing at the initial evaluation of adolescents with hypertension includes the urinalysis, blood urea nitrogen, creatinine, electrolytes, and complete blood count. Because cardiovascular risk factors may cluster in patients, particularly when obesity and the metabolic syndrome are present, it is useful to assess the fasting lipid profile. Abnormalities in the history and physical examination may suggest additional laboratory tests to evaluate the possibility of secondary hypertension. Finally, with persistent blood pressure elevation, a renal ultrasound study may provide important information about structural abnormalities of the urinary tract.

Some adolescent patients may have blood pressure elevation only in the physician’s office or under other stressful conditions. This is often referred to as white coat hypertension. Assessment of possible white coat hypertension can be accomplished by home blood pressure measurement or with 24-hour ambulatory blood pressure monitoring. When home blood pressure measurements are normal or when ambulatory monitoring reveals less than 20% of blood pressures above the ninety-fifth percentile, then the diagnosis of white coat hypertension should be entertained. Conversely, it is not clear that patients with white coat hypertension should be considered to have normal blood pressure. There is evidence to


suggest that these patients are at risk for future, persistent hypertension.