Abstract
Bilateral hydronephrosis is classic for supravesical obstructive uropathy causing uraemia with dual functioning kidneys. Recently, a patient presented with uraemia and metastatic urinary bladder carcinoma but only unilateral right-sided hydronephrosis. A right ureteral stent was placed retrograde and no further intervention was planned since the left kidney appeared normal, and since the left ureteric orifice was not visualized. We insisted on a left percutaneous nephrostomy which was successful with prompt urine return. A left nephrostogram revealed unrecognized hydroureter/hydronephrosis. Following haemodialysis, kidney function normalized at 3 weeks. For symptomatic uraemia from obstruction, an antegrade and/or a retrograde decompression must be attempted bilaterally to improve renal salvage.