Giant hydronephrosis - A diagnostic dilemma

We report a complex case in which the left kidney had undergone giant hydro nephrotic change after chronic obstruction at the vesicoureteric junction. Minor blunt abdominal trauma caused rupture of the parenchyma of this expan ded and dilated kidney, with bleeding into its collecting system. The mixtu re of blood and urine remained contained within the kidney's structural lay ers, so producing a tense, cystic, fluid-filled mass arising from the left hypochondrium. Pathogenesis, differential diagnosis and investigation of gi ant hydronephrosis and its rupture are discussed. The observation is made t hat gross distortion of the renal parenchyma by rupture or hydronephrosis i mpairs arterial inflow to the kidney.