Publications
Solitary Functioning Kidney in High Anorectal Malformation
Rajkiran, Srinivas Raju, Das, Kanishka Abstract
Aim:
A solitary functioning renal unit in high anorectal malformation may harbor anomalies in the upper/lower urinary tract that further compromise renal function and accelerate hyperfiltration injury. We aimed to analyze the clinical course, management, and outcome of children with a solitary renal unit and high anorectal malformation.
Materials and Methods:
A cohort of solitary renal units in anorectal malformation managed between 2000 and 2015 with a defined protocol at a pediatric nephro-urology clinic are included in the study. Investigations and management were individualized according to issues in the agenetic/dysplastic unit, solitary functioning unit, or bladder-urethra. Clinical details, management, and outcome were analyzed.
Results:
Of 53 cases of high anorectal malformation with urologic anomalies, 17 (32%) had single kidneys. Majority (10/17, 59%) had another complicating urinary tract anomaly, four being uremic at presentation. Nearly half had multiple urinary infections including epididymo-orchitis unrelated to the rectourinary fistula and warranted additional stoma (bowel/urinary) or other urinary tract surgery. At a mean follow-up of 70 months, majority (14/17, 82%) have a preserved solitary renoureteric unit while the remaining three await renal replacement therapy.
Conclusion:
Solitary functioning renal units associated with high anorectal malformation in children need meticulous investigation and surveillance to facilitate renal preservation. The implications of the associated rectourinary fistula, vesicoureteral reflux, urinary infections including epididymo-orchitis, and other urinary tract anomalies on the conventional surgical management are illustrated.
INTRODUCTION
Unilateral renal agenesis is a common associated urinary tract anomaly in high anorectal malformation.[1] The remnant solitary functioning kidney with an intrinsic potential for hyperfiltration injury[2] may also have varying degrees of congenital or acquired, structural, or functional affliction that compromise renal parenchymal function. Lower urinary tract factors including neurovesical malfunction and contamination from rectourinary fistula further complicate the issue. We present a critical analysis of the clinical course, management dilemmas, and outcome of a cohort of solitary renal units in high anorectal malformation.
MATERIALS AND METHODS
All cases of high anorectal malformation with a solitary functioning renal unit managed and followed up at a multidisciplinary pediatric nephro-urology clinic of a tertiary teaching hospital according to a protocol between 2000 and 2015 were included in the study. After a routine ultrasound confirmed the solitary renal unit, they were placed on antibiotic uroprophylaxis. A voiding cystourethrogram was carried out either during the distal cologram study or in the interim to detect vesicoureteral reflux and confirm bladder evacuation. A renal cortical scintigraphy (dimercaptosuccinic acid) evaluated the baseline parenchymal reserve and prenatal scarring/hypodysplasia. In case of urinary tract dilatation, a diuretic renogram (diethylene triamine pentaacetic acid) with a bladder catheter in situ was obtained to rule out obstruction. A panel of biochemical tests (serum creatinine, venous blood gas-bicarbonate, pH, and urinary microalbumin) evaluated renal status and the need for adjuvant renoprotective medications (calcium, bicarbonate, alpha calcidiol, and angiotensin-converting-enzyme inhibitors). Additional investigations (e.g., magnetic resonance imaging and urodynamic studies in neurovesical dysfunction) were conducted when indicated. Specific surveillance of a solitary renal unit at follow-up included tracking of hypertension, annual renal length for compensatory hypertrophy, and quantitative urinary microalbumin estimation. The management and follow-up was individualized according to the structural and functional pathology.
This is a retrospective review of case records and follow-up evaluation with patient recall. Age at diagnosis of urinary malformation, sex, birth weight, consanguinity, details of antenatal diagnosis, and associated anomalies (cardiac, genital, sacral spinal) were noted. Clinical presentation, baseline investigations including biochemistry, imaging, and serial observations of these were studied. Details of clinical course, especially urinary tract infections (VUR), medical and surgical management (creation and closure of urinary and bowel stoma, additional urinary tract surgical interventions), and outcome of the urinary tract malformation were collated and analyzed.
RESULTS
Demography and referral pattern
Table 1 details the clinical profile and management of the cases. Of 95 cases of high anorectal malformation managed during this period, 53 (56%) had associated genitourinary anomalies. Out of 53 patients, 17 (32%) had a solitary functioning renoureteric unit. All but one were males, all were born at term with an average weight of 2.4 kg. Out of 17 cases, 3 (18%) were born to consanguineous parents. Antenatal anomaly scans were either not available or failed to detect the solitary kidney. Seven cases were born at this center and ten elsewhere; six of the latter ten cases were transferred and managed here from the neonatal period while four reported later (4–108 mos). The diagnosis of a solitary renal unit was made at birth/during infancy in 14/17 (82%) and later in 3/17 (18%). Thus, 13/17 (76%) cases were on our management protocol from the neonatal period onward.
