Prerenal failure is traditionally accompanied by oliguria and
represents the normal renal adaptation to retain salt and water
and correct the prerenal state. Nonoliguria occurring in the
setting of acute renal failure usually represents acute tubular
necrosis (ATN) since the kidney has lost its ability to extract salt
and water. We report nine cases of patients with acute renal
failure occurring in the setting of impaired systemic hemodynamic states and yet who were nonoliguric without strong
evidence for ATN. The common defect in these subjects with
"polyuric prerenal failure" was a blunted urinary concentrating
ability. Polyuria and renal failure occurring despite evidence for
impaired systemic hemodynamics may not necessarily be ATN,
may still be prerenal, and should be recognizable and promptly
reversible if treated appropriately.
(Arch Intern Med 140:907-909, 1980)