Objective: Nephrogenic diabetes insipidus (NDI) with dilatation of upper urinary tract and bladder is rarely reported. This study evaluated the urological manifestations and treatment results of this rare condition.
Material and methods: According to a fluid deprivation test, seven men and two women were diagnosed as NDI, and underwent ultrasonography, magnetic resonance urography, cystography, and urodynamic and laboratory examination. A micturition diary and symptoms were recorded before and during treatment. All patients were given hydrochlorothiazide and followed up with ultrasonography, the postvoiding residual volume (PVR), urinalysis and kidney function tests.
Results: All patients presented with polydipsia and polyuria with severe dilatation of upper urinary tract and bladder. Urodynamics showed that the mean values of the bladder capacity, bladder pressure at the end of filling, maximum flow rate (Q(max)), detrusor pressure and PVR were 1056.3 ml, 40.5 cmH(2)O, 30.8 ml/s, 51.3 cmH(2)O, 436.3 ml, respectively. The total urine volume in all patients decreased by more than 50% after administration of hydrochlorothiazide, which improved the symptoms and hydronephrosis in seven cases. The symptoms of other two cases were relieved after treatment with an electric transurethral incision of the bladder neck and a cystostomy.
Conclusions: NDI should be considered in patients with dilatation of the urinary tract and polyuria. Higher bladder pressure at the end of filling may contribute to the dilatation of urinary tract. Normal detrusor contractility with large PVR is a unique manifestation of this condition. Controlling the urine volume and reducing the PVR are of key importance in the treatment of this condition.