Utility of renal imaging in the diagnostic evaluation of obese childhood primary hypertension

Although childhood primary hypertension (CP-HTN) associated with obesity is considered an earlier manifestation of typical adult-onset primary hypertension (adult-HTN), the recommendations for diagnostic evaluation are not identical in the two conditions. In particular, renal imaging is not recommended in adult-HTN, but is still currently recommended in CP-HTN. In this study, the clinical value of renal imaging in the initial diagnostic evaluation of CP-HTN was determined. A retrospective chart review was conducted of older and overweight children (> 7 years of age) evaluated in the pediatric nephrology clinic at the University of Florida from 1999 to 2004 for hypertension. The final highly selected study group was composed of obese or overweight children (body mass index > 85th percentile for age and gender) with otherwise unremarkable history, physical examination, and urinalysis. Renal imaging was performed (ultrasound in 49, computed tomography in one) in 50 patients (M:F = 28:22; age range, 7-20 years) with clinical features compatible with CP-HTN, and was normal in all patients. In this study, renal imaging did not add any clinical value to the initial evaluation of CP-HTN associated with obesity. Larger studies may confirm that the evaluation of CP-HTN in older obese children could be similar to guidelines for evaluation of adult-HTN.