An unusual cause of renovascular hypertension in a pediatric patient with chronic kidney disease

Abstract

Background: Renovascular hypertension (RVH) accounts for 5-10% of arterial hypertension in children and is most commonly caused by fibromuscular dysplasia. Sporadically, renal artery stenosis in pediatric patients is caused by extrinsic compressive masses. Case report: A 12-year-old patient with complex urinary tract defect (dysplastic left kidney -nephrectomy at 11 months, right ectopic kidney in the midline, behind the urinary bladder), chronic kidney disease (CKD) stage 2, and arterial hypertension was admitted to the hospital due to worsening of kidney function during angiotensin-converting enzyme inhibitor (ACE-I) therapy. CT angiography revealed a right ectopic kidney located above the bladder, supplied by a single renal artery originating from the right common iliac artery. The renal artery had a tortuous shape with width in the ostium approx. 4.5 mm; then, the artery was bent and ran between the common iliac artery and the kidney. Ultrasound performed with a filled bladder showed bending and stenosis of the renal artery at the origin from the right common iliac -peak systolic velocity (PSV) 4.5-5.5 m/s and renal-aortic ratio (RAR) 3.1. With an empty bladder, no bending or stenosis was visible (PSV 1.7-1.9 m/s and RAR 1.0). Uroflowmetry revealed a dysfunctional micturition curve, large bladder capacity, and post-void urine retention. ACE-I was changed to beta-blocker and doxazosin, which led to blood pressure and kidney function normalization. Conclusions: Renal ectopia associated with bladder dysfunction may result in renal artery stenosis causing renovascular hypertension.