Transitional nephrology.

During growth from fetal life to early childhood, renal function and parameters used to assess renal function undergo developmental changes. This article provides a brief review of these maturational changes and how they affect the evaluation and management of young patients with diseases affecting the genitourinary system. Included is a discussion of renal blood flow, glomerular filtration, sodium and water balance, clinical assessment of renal function, and age-related effects of nephrotoxins.