Article: Renal failure

Renal failure is the condition where the kidneys fail to function properly. Physiologically, renal failure is described as a decrease in the glomerular filtration rate. Clinically, this manifests in an elevated serum creatinine. It can broadly be divided into two categories: acute renal failure and chronic renal failure.

• Chronic renal failure (CRF) develops slowly and gives few symptoms initially. It can be the complication of a large number of kidney diseases, such as IgA nephritis, glomerulonephritis, chronic pyelonephritis and urinary retention. End-stage renal failure (ESRF) is the ultimate consequence, in which case dialysis is generally required until a donor for a renal transplant is found.
• Acute renal failure (ARF) is, as the name implies, a rapidly progressive loss of renal function, generally characterised by oliguria (decreased urine production, quantified as less than 400 to 500 mL/day in adults, less than 0.5 mL/kg/h in children or less than 1 mL/kg/h in infants), body water and body fluids disturbances and electrolyte derangement. An underlying cause must be identified to arrest the progress, and dialysis may be necessary to bridge the time gap required for treating these underlying causes.

Acute renal failure can present on top of (i.e., in addition to) chronic renal failure. This is called acute-on-chronic renal failure (AoCRF). The acute part of AoCRF may be reversible and the aim of treatment, like in ARF, is to return the patient to their baseline renal function, which is typically measured by serum creatinine. AoCRF, like ARF, can be difficult to distinguish from chronic renal failure, if the patient has not been followed by a physician and no baseline (i.e., past) blood work is available for comparison.

Before the advancement of modern medicine renal failure might be referred to as uremic poisoning. Uremia was the term used to describe the contamination of the blood with urine. Starting around 1847 this term was used to describe reduced urine output, now known as oliguria, that was thought to be caused by the urine mixing with the blood instead of being voided through the urethra.