Diabetes mellitus: the predominant cause of bilateral renal enlargement.

The authors reviewed 102 cases of bilateral renal enlargement seen on excretory urography (excluding hydronephrosis and duplex kidneys) to determine the clinical significance of this finding. Associated abnormalities were found in 48 patients, including diabetes mellitus in 29; nondiabetic obesity, large body structures, or chronic steroid use in 16; acromegaly in 1; and unknown etiology in 37, 2 of whom were found to have diabetes five years later. Because of the striking preponderance of diabetes in this study, a fasting blood glucose analysis is recommended for patients with unexplained bilateral renal enlargement on excretory urography.