Duplex kidney: Not just a drooping lily

Abstract

Introduction: Duplex kidneys are common, mostly asymptomatic and of no clinical significance. However, they can be associated with significant pathology, often with long-term morbidity. There is minimal literature on the review of the duplex kidney, its associated anomalies and complications. The purpose of this paper is to review our experience of imaging the spectrum of abnormalities associated with duplex kidneys in the paediatric population and correlate this with contemporary literature. Method: A retrospective review of the radiology database in a tertiary paediatric centre was performed. A word search of the Radiology Information System for 'duplex' of patients under the age of 16 was undertaken and limited to studies performed between 2006 and 2013. Results: Two hundred seventy-four patients were identified (age range 0-16, median 3 years, gender 59.9% female) who had 836 studies: ultrasound 598/836 (71.6%), nuclear medicine 180/836 (21.5%), micturating cystourethrogram 52/836 (6.2%), MRI 5/836 (<1%) and CT scan 1/836 (<1%). Patients were categorised as duplex and no complication (151/ 274 = 55.1%), upper moiety obstruction, lower moiety reflux/scarring, multicystic dysplastic kidney, abnormal ureteric insertion and other pathology. Conclusion: Duplex kidneys are common and often not clinically significant. However, this study demonstrates almost 50% of paediatric patients investigated for duplex kidneys had complications requiring treatment. The most common complications were upper moiety obstruction associated with a ureterocele and lower moiety vesicoureteric reflux. Ultrasound was the most common modality for early detection of these complications.

Renal Tumors of Childhood: Radiologic-Pathologic Correlation Part 1. The 1st Decade:From the Radiologic Pathology Archives

“…Segmental cystic renal dysplasia poses a greater diagnostic challenge because some normal renal parenchyma is present. Usually segmental dysplasia occurs in a duplex kidney, so evidence of complete duplication, such as ectopic ureterocele, is helpful in suggesting the diagnosis (53,55,56).…”

The left ureterocele and stone of calyceal diverticulum in the patient with bilateral incomplete duplex kidneys managed by flexible ureteroscopy: a case report and literature review

“…Due to the unique anatomical abnormalities of duplex kidney and ureter malformations, it is easy to appear urine drainage [18]. The drainage can result in upper urinary tract obstruction, infection, calculi and other complications.…”

“…Upper moiety complications are related to the ureteral ectopic insertion, usually complicated with a ureterocele or multi-cystic dysplastic moiety kidney. Males may occur a pelvic mass if urine gradually drains into an accessory sexual structure; Females can experience urinary incontinence when the inserting position is under the urethral sphincter [18,20]. The most common upper moiety complication is urinary tract obstruction due to a ureterocele [4].…”

“…The most common upper moiety complication is urinary tract obstruction due to a ureterocele [4]. Lower moiety complications are mainly caused by the lateral shift of the ureters insertion into the bladder and consist of VUR, renal scarring and pelviureteric junction (PUJ) obstruction [18]. The most prevalent lower moiety complication is VUR and it can lead to recurrent urinary tract infections (UTIs) which may have a permanent impairment on renal function [21,22].…”

Gene‐targeted deletion in mice of the Ets−1 transcription factor, a candidate gene in the Jacobsen syndrome kidney “critical region,” causes abnormal kidney development

“…Duplex ureter/duplex kidney is one of the most common congenital kidney defects in humans (Doery, Ang, & Ditchfield, ). This condition can result in a kidney which has two separate collection systems and two ureters (complete duplex) or a kidney with two incomplete duplications of the renal pelvis and ureter (partial duplex; Siomou et al, ).…”