Pediatric Hypertension Clinical Presentation

A well-taken history provides clues about the cause of hypertension and guides the selection and sequencing of ensuing investigations. Presenting symptoms and signs are not specific in neonates and are absent in most older children unless the hypertension is severe.

Relevant information includes the following:

• Prematurity
• Bronchopulmonary dysplasia
• History of umbilical artery catheterization
• Failure to thrive
• History of head or abdominal trauma
• Family history of heritable diseases (eg, neurofibromatosis, hypertension)
• Medications (eg, pressor substances, steroids, tricyclic antidepressants, cold remedies, medications for attention deficit hyperactivity disorder [ADHD])
• Episodes of pyelonephritis (perhaps suggested by unexplained fevers) that may result in renal scarring
• Dietary history, including caffeine, licorice, and salt consumption
• Sleep history, especially snoring history
• Habits, such as smoking, drinking alcohol, and ingesting illicit substances

Signs and symptoms that should alert the physician to the possibility of hypertension in neonates include the following:

• Failure to thrive
• Seizure
• Irritability or lethargy
• Respiratory distress
• Congestive heart failure

Signs and symptoms that should alert the physician to the possibility of hypertension in older children include all of the above, as well as the following:

• Headache
• Fatigue
• Blurred vision
• Epistaxis
• Bell palsy

Measurement and recording of blood pressure

Best medical care includes yearly measurement of blood pressure (BP) in every child older than 3 years, preferably by means of auscultation with a mercury gravity manometer. Doppler and oscillometric techniques can be used in children in whom auscultatory BP measurements are difficult to obtain. Measurements obtained with oscillometry that exceed the 90th percentile should be repeated with auscultation. Measurements repeated over time are required to obtain meaningful information.

Proper cuff size is essential for accurate measurement of BP. The width of the rubber bladder inside the cloth cover should cover at least 40% of the patient’s arm circumference at a point midway between the olecranon and the acromion. The length of the bladder in the cuff should cover 80-100% of the circumference of the arm. If a cuff is too small, the next larger cuff size should be used, even if it appears too large.

The child should be relaxed and in a comfortable, preferably sitting, position with the feet on the floor and the back supported. The patient’s right arm should be resting on a supportive surface at the level of the heart. Infants can be examined while supine.

The cuff should be inflated at a pressure approximately 20 mm greater than that at which the radial pulse disappears, then allowed to deflate at a rate of 2-3 mm Hg/s.

The first Korotkoff sound (ie, appearance of a clear tapping sound) defines the systolic pressure, whereas the fifth Korotkoff sound (ie, disappearance of all sounds) defines the diastolic pressure. The fourth (low-pitched, muffled) sound and the fifth sound frequently occur simultaneously, or the fifth sound may not occur at all. Diastolic BP must be recorded. When Korotkoff sounds can be heard down to 0 mm Hg, the BP measurement should be repeated with less pressure applied to the head of the stethoscope than was applied before.

Systolic BP in the lower extremities must be measured when elevated systolic BP in the upper extremities is first noted, regardless of whether the amplitude of the arterial pulse seems lower in the legs than in the arms. Increased systolic pressure in the arm suggests coarctation of the aorta. If found, systolic pressure must also be measured in the left arm and leg.

With the patient in the supine position, place a cuff on the calf. The cuff should be wide enough to cover at least two thirds of the distance from knee to ankle. Doppler sonography can be used to detect onset of blood flow, which reflects systolic BP, in the posterior tibial or dorsalis pedis artery. The value should be compared with a similarly obtained Doppler systolic BP in the arm, again with the patient supine.

Remember that the artifact of distal pulse amplification causes the measured systolic BP at the brachial artery to be less than that at the posterior tibial or dorsalis pedis artery. This difference may be only a few millimeters of mercury in the infant but can rise to 10-20 mm Hg in the older child or adult. The magnitude of this artifact is directly proportional to the pulse pressure. In a patient with chronic aortic regurgitation, for example, the difference in measured systolic pressure may exceed 40 mm Hg.

At no time should the systolic pressure in the arm exceed that in the foot. If it does, pressures in both arms and legs should be measured. Consistent recording of high arm systolic pressure indicates aortic coarctation. High pressure in only the right arm suggests that an obstruction is present proximal to the origin of the left subclavian artery.

Interpretation of blood pressure values

Hypertension is defined as an average systolic or diastolic BP above the 95th percentile. Any child with a BP exceeding the 90th percentile requires scrutiny.

Patients with severe hypertension and target-organ damage require immediate attention. For other patients, several measurements of BP should be made at weekly intervals to determine if the elevation is sustained.

The average of multiple measurements should be plotted on an appropriate percentile chart. If the average measurement is between the 90th and 95th percentiles (ie, the patient is prehypertensive) the child’s BP should be monitored at 6-month intervals. If the average BP is greater than the 95th percentile, the child should be evaluated further and therapy considered.

Patients with stage I hypertension should be seen again in 1-2 weeks. Those with stage II hypertension should be reevaluated in 1 week or sooner if the patient is symptomatic.

So-called white-coat hypertension is diagnosed in a patient who has a BP above the 95th percentile when measured in the physician’s office but who is normotensive outside the clinical setting. Ambulatory monitoring of BP usually is required to diagnose white-coat hypertension.

Identification of signs of secondary hypertension

A primary objective of the physical examination is to identify signs of secondary hypertension. The following should be evaluated to assess for potential causes of the hypertension:

• Body mass index, to assess for metabolic syndrome
• Tachycardia, to assess for hyperthyroidism, pheochromocytoma, and neuroblastoma
• Growth retardation, to assess for chronic renal failure
• Café au lait spots, to assess for neurofibromatosis
• Abdominal mass, to assess for Wilms tumor and polycystic kidney disease
• Epigastric or abdominal bruit, to assess for coarctation of the abdominal aorta or renal artery stenosis
• BP difference between upper and lower extremities, to assess for coarctation of the thoracic aorta
• Thyromegaly, to assess for hyperthyroidism
• Virilization or ambiguity, to assess for adrenal hyperplasia
• Stigmata of Bardet-Biedl, von Hippel-Lindau, Williams, or Turner syndromes
• Acanthosis nigricans, to assess for metabolic syndrome