An eight-year-old Caucasian girl is referred for further evaluation after a routine school health examination showed a blood pressure of 150/90 mmHg, even after adequate rest. She is completely asymptomatic. She has no medical history of clinical significance. She is not on any medications, including over-the-counter drugs or herbal supplements. Her family history is unremarkable. Her growth and development are normal. All immunizations are up-to-date. Her nutritional status is good. A complete blood count is within normal parameters.
Serum creatinine: 0.58 mg/dL (0.44-0.72) Blood urea nitrogen: 13 mg/dL (7-20) Serum Na+: 132 mEq/L (132-140) Serum K+: 3.8 mEq/L (3.5-4.8) Serum Cl-: 101 mEq/L (95-102)
Plasma renin activity: 10.5 ng/mL/hour (0.5-5.9)
Both kidneys are of normal size. The left kidney shows a pulsus parvus et tardus Doppler waveform, with a renal arterial resistive index (RI) of 0.9 (normal: <0.5). The right kidney shows normal Doppler waveforms and a renal artery RI of 0.4.
There is focal stenosis (~60%) of the middle and distal portions of the left renal artery. Multiple collaterals are present. The right renal artery and abdominal aorta appear normal.