[Obstructive anuria with non-dilated cavities].

Four patients with no evidence of acute functional or organic renal failure suddenly developed anuria. Repeated ultrasonographic exploration failed to show any dilatation of the urinary tract. After 4, 5, 7 and 34 days of anuria respectively, an obstacle was detected, located and identified by ultrasonically guided antegrade pyelography, which led to immediate urine derivation by percutaneous nephrostomy. Three of these patients were cured by percutaneous techniques alone. These 4 cases represent a small but not negligible part of a series of 74 patients with obstructive anuria, 70 of whom had dilated renal cavities. They throw doubt not on the reliability of ultrasonography, but on the idea that all obstacles are associated with dilatation upstream. They also confirm that opacification of the urinary tract is the only way of making sure that an obstacle is present. Antegrade pyelography gives excellent contrast images and can be used as first stage of a percutaneous nephrostomy. The other diagnostic methods are fraught with a high proportion of inadequacy or failure.