Acute Renal Failure: Diagnosis
Azra Sehic MD1
Russell W. Chesney MD1
1 Division of Nephrology, Department of Pediatrics, University of Tennessee College of Medicine, Memphis, TN.
Introduction
Although acute renal failure (ARF) is relatively uncommon, its mortality rate is potentially so high that it is important to recognize this condition in children. Rapid deterioration of renal function is caused by numerous insults and results in typical findings, including extracellular volume expansion, hyperkalemia, hypertension, metabolic acidosis, and azotemia. It usually is reversible, with the majority of patients recovering completely. However, ARF can lead to residual impairment of renal function and progress to end-stage renal disease and death. Conservative medical treatment often is life-saving.
Definition
ARF represents the rapidly progressive (within several hours or days) cessation of renal function, which results in the inability of the kidney to control body homeostasis, manifesting in retention of nitrogenous waste products (azotemia) and fluid and electrolyte imbalance. On the basis of pathophysiologic process, ARF has been divided broadly into three diagnostic categories: prerenal, intrarenal (organic-intrinsic), and postrenal failure (Table 1). Prerenal and early postrenal failures are renal functional disorders and responses of a structurally intact kidney to extrarenal processes. These forms of renal dysfunction recover rapidly as soon as the cause is reversed. However, if these two disorders are not recognized in time, persist too long, or are treated inadequately, they can result in intrinsic renal failure.
