Extrarenal azotemia, it seems to us, is a nonspecific term that has been used to describe such varied conditions as acute renal insufficiency, reversible uremia, lower nephron nephrosis, shock kidney and crush syndrome. The use of these terms almost interchangeably in the literature has resulted in considerable confusion. It is probable that many of the conditions classified under these headings are of different pathogenesis and that the pathological picture in the kidney will vary. Also, the pathogenesis may be of extreme diversity, varying from peripheral vascular collapse in acute toxemias to late secondary shock in traumatic injuries and including medical, surgical, obstetric, dermatological and orthopedic conditions. Because of such diversity, it seems improbable that the renal effect is always identical.
It has been our observation that there were occasional cases in which a disproportion in the relation between creatinine and nonprotein nitrogen existed. It was our general impression that this
GABERMAN P, ATLAS DH, KAMMERLING EM, EHRLICH L, ISAACS J. RELATION OF CREATININE TO NONPROTEIN NITROGEN IN AZOTEMIC STATES. JAMA. 1950;144(15):1246-1249. doi:10.1001/jama.1950.02920150020006