Duplex Kidneys Unraveled Chris Driver Aberdeen

Duplication Anomalies 0.8% population 40% bilateral Inheritance autosomal dominant incomplete penetrance 8% in siblings of index case

Types of duplex complete incomplete 2 UO’s VERY rarely 2 kidneys 1 UO only divided outside bladder usually no clinical issues

Embryology Ureteric Bud Induces Renal Differentiation

Duplex ureters cross over

Mackie Stephen’s Hypothesis J Urol 1975 ↑distance from orthotopic site = ↑ dysplasia

Duplex MOST DUPLEXES ARE CLINICALY IRRELEVANT Upper Moiety Low / ectopic orifice Lower Moiety High Lateral orifice

If the lower moiety is ectopic.... lateral UO VU reflux dysplasia

Management of Reflux in Duplex indication UTI progressive scarring less likely to resolve spontaneously STING or HIT En Bloc reimplantation lower pole hemi-nephroureterectomy

If the upper moiety is ectopic..... low UO obstruction, ureterocele extra-vesical ectopic

C:\ Ureterocele

Management of Duplex Ureterocele indications obstruction especially bladder neck hydronephrosis loss of function UTI remember.....single system (non duplex) ureterocele is rare

Endoscopic Puncture definitive (temporising) Risk = induced reflux

Definitive management No upper pole function - Upper pole nephrectomy

Definitive management Good upper pole function, big ureterocele - Uretero-ureterostomy

Definitive management Good upper pole function, small ureterocele – en bloc reimplantation

Definitive management No upper pole function, obstructing ureterocele - heminephroureterectomy

Ectopic Ureter “she’s always wet, doctor.....” primary continuous normal voiding pattern otherwise can be very wet....

Extravesical Ectopic Ureter females HN HU usually BUT may not be associated with dilatation small dysplastic upper moiety “CRYPTIC DUPLICATION”

Investigation of Cryptic Duplication USS- may miss small non-dilated IVU- may miss poor function, clues Retrograde Pyelogram....difficult ++ MRU new gold standard

If so small, why so wet? DYSPLASTIC RENAL TISSUE GOOD RENAL TISSUE GFR 1ml/min 60 mls/hour <50% reabsorption in tubules Urine output 30 mls per hour = 720mls/day = very wet! GOOD RENAL TISSUE GFR 100ml/min 6000 mls /hour 99.9% reabsorption in tubules Urine output 60 mls per hour

Summary Duplex lower moiety: Reflux upper moiety: Obstruction ectopic orifice: Incontinence