Recent reviews have claimed that the majority of patients with the nephrotic syndrome have plasma volume expansion (that is, they are overfilled). Here we attempt to re-establish balance to the debate on body fluid volume status in nephrotic patients by: (a) discussing the conflicting literature on plasma volume measurements in the nephrotic syndrome; (b) providing alternate explanations for data purporting to support an overfill hypothesis in the nephrotic syndrome; (c) emphasizing secondary neurohumoral responses that support underfilling at least as frequently as overfilling; and (d) emphasizing the clinical importance of fluid assessment in the individual patient with the nephrotic syndrome particularly in relation to diuretic use.
