Differential Diagnosis of Oliguria in Aged Patients

A DECREASE in extracellular-fluid or blood volume may result in oliguria by the following mechanisms: diminished renal perfusion, without associated damage to the renal tubular cells; or acute tubular insufficiency, with or without necrosis of the tubular cells.¶ 2 It is of clinical importance to differentiate these two mechanisms, since in the first fluidreplacement therapy may prevent the development of tubular insufficiency.2 3 4 In some cases it may be difficult, if not impossible, to establish the proper diagnosis on the basis of history, physical examination, urinalysis or urine volume. In such circumstances it has been emphasized that the concentration of total solutes . . .