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S3-3
(CP)
URINARY TRACT CHANGES IN CHILDREN WITH NEPHROGENIC DIABETES
INSIPIDUS
Ajaykumar GUNTAKA
1
, Venkatesh K
2
and Prassanna V
3
1) KLE'S Dr. Prabhakar kore Hospital Belgaum, INDIA, Department of Urology, Belagaum, INDIA - 2) NU Hospitals
(South), Department of Urology, Bangalore, INDIA - 3) NU Hospitals (South), Bangalore, INDIA
PURPOSE
Congenital nephrogenic diabetes insipidus is characterized by insensitivity of the distal nephron to arginine vasopressin.
Urinary tract dilatation develops in children affected with NDI, as well as other polyuric syndromes, probably due to the
large volume of urine produced. We report our series of children with severe distension of the urinary collecting system
secondary to persistent polyuric state.
MATERIAL AND METHODS
All patients were evaluated annually, including imaging of their urinary tract by renal sonograms and voiding
cystourethrograms. NDI was diagnosed clinically, based on hyposthenuric urine during events of hypernatraemic
dehydration, which did not respond to exogenous desmopressin. Conventional therapy, including hydrochlorothiazide,
indomethacin and low-salt diet, was initiated at diagnosis. Children underwent an urodynamic study, using standard
methods. The investigation comprised full pressure-flow recordings, on an outpatient basis, using a Laborie urodynamic
instrument.
RESULTS
The patient group included seven children and adolescents with NDI. Mean urine osmolarity at diagnosis was
89±25mosm/l. Hydroureteronephrosis was observed in all children , beginning at age 3 years . Sonography also
revealed markedly enlarged. Mean bladder volume was 1233±628 ml and all of them had a significant post-voiding
residue (>1000 ml) . Urodynamic studies , revealed a hypotonic-large-capacity, high compliant (as high as 74ml/cm
H2O) type of neurogenic bladder . Bladder residual was as high as 1000ml. Two children were initiated on a clean
intermittent catheterization regimen, which improved the bladder appearance but could not solve the daytime enuresis.
Two other children had suprapubic catheter drainage. Impairment in kidney function, including serum creatinine and low
molecular weight proteinuria was observed in two children.
CONCLUSIONS
The severe renal concentrating defect in children with NDI is associated with the development of hydroureteronephrosis
followed by huge distension of bladder and dysfunction. Careful follow-up is needed in order to assure that no bladder
outlet obstruction and/or renal insufficiency develop .