The differential diagnosis of the unilateral small kidney.

Although it is frequently possible to determine the cause of an unilateral small kidney, there are cases where the renal damage is so advanced, or the interference to growth and maturation so extensive, that the etiology cannot be established. High-dose urography with tomography during the nephrographic phase are required for a confident diagnosis. Ureteral compression should be used to improve calyceal visualization. This technique can be adapted for children. Complementary diagnostic procedures are often needed, both in adults and in children. We cannot emphasize enough the need for clinical correlation and comparision with previous examinations.