Non-dilated obstructive uropathy - an unrecognized cause of acute renal failure in hospitalized US patients: three case reports seen over 6 months in a northwestern Wisconsin nephrology practice.

The syndrome of non-dilated obstructive uropathy (NDOU) and acute renal failure (ARF) is well reported. However, the literature suggests that this syndrome is rare, accounting for less than 5% of cases of urinary obstruction. Our recent experience with three cases of NDOU seen within a space of months implies otherwise. Between March 2009 and October 2009, in a small Midwestern American town Nephrology practice, we successfully managed three cases of NDOU. They all presented with newly symptomatic ARF. Renal imaging revealed no dilatation in both kidneys in one, only unilateral dilatation in the second, and dilatation was absent in a single functioning kidney in the third. They comprised of two males and one female, mean age 61 years (peak creatinine: 320-880 μmol/L). Despite the absence of dilatation on renal imaging, strong suspicion for NDOU led to decompression procedures with prompt recovery of kidney function in all three patients - two required percutaneous nephrostomy tube placements and/or ureteric stents and one responded to simple Foley catheter drainage. One required temporary hemodialysis. We submit that NDOU may be more common than previously speculated. A high index of suspicion is warranted as significant renal salvage can often be achieved by timely decompression procedures.