What is renal failure?
Renal failure, also called kidney failure, renal insufficiency, or end-stage renal disease (ESRD), can be defined as a decline in kidney function sufficient to result in the retention of metabolic waste material in the body. The loss of the ability of the kidneys to excrete waste material is often progressive, culminating in complete renal failure in untreated cases. Although kidney disease can occur at any age, most cases occur in adults, frequently as a complication of diabetes and/or hypertension.
There are three major causes of renal failure. The first, prerenal, results from obstruction of the renal artery because of vascular causes such as hypertension. The decreased blood flow to the kidney causes tissue destruction and loss of renal function. Prerenal causes may also be linked to liver disease and congestive heart failure. The second major cause of renal failure is a direct breakdown of kidney function as a result of inflammatory processes associated with infection. Certain drugs may also have toxic effects on kidney function. The third major cause of renal failure is postrenal, which refers to obstructions that block the flow of urine from the kidney.
The body cannot survive without at least one functioning kidney. As a consequence of renal failure, toxic metabolic wastes accumulate in the bloodstream, such as urea nitrogen produced in the metabolism of proteins. Renal failure also results in disturbances of electrolyte balance, associated with high levels of sodium, potassium, and other salts. Other complications include compromised cardiovascular function, pulmonary edema, gastrointestinal symptoms, chronic fatigue, and infections.
Acute renal failure can be treated effectively with hemodialysis and/or kidney transplantation. The hemodialysis machine has made it possible to extend the lives of many patients. This external device filters the blood as it traverses fluid-bathed semipermeable membrane filters that remove metabolic wastes while permitting the retention of essential blood components. Blood leaves the body and returns postfiltration through a fistula or access joint inserted under the skin to link arterial and venous blood flow. Dialysis must be carried out on a regular basis and requires several hours.
The best treatment for renal failure is a kidney transplant. Sadly, there are not enough donor kidneys to meet the need; patients who do receive organ donations may wait for years before transplantation occurs. As of 2013, United Network for Organ Sharing data show that about one million people in the United States have ESRD and more than 95,000 are on the waiting list to receive a kidney donation. Research continues on an artificial kidney that would replicate the delicate filtering functions of the kidney’s glomeruli. A study published in the journal Nature Medicine in April 2013 reported that scientists have been able to bioengineer working kidneys in rats. While the kidneys lacked the full function of normal kidneys and much more work needs to be done, the milestone represents a promising step towards the goal of creating fully functional artificial kidneys from the cells of patients in need of a transplant.
Aronoff, George. Kidney Failure: The Facts. New York: Oxford University Press, 1996.
Brenner, Barry M. et al., eds. Brenner and Rector’s The Kidney. 9th ed. Philadelphia: Saunders/Elsevier, 2012.
HealthDay. "'Bioengineered' Kidneys Show Promise in Rat Study." MedlinePlus, April 15, 2013.
MedlinePlus. "Kidney Failure." MedlinePlus, May 20, 2013.
Mitch, William E., and Saulo Klahr, eds. Handbook of Nutrition and the Kidney. 6th ed. Philadelphia: Lippincott Williams & Wilkins, 2010.
Molitoris, Bruce A., and William Finn, eds. Acute Renal Failure. Philadelphia: W. B. Saunders, 2001.
Savitsky, Diane. "Kidney Failure." Health Library, October 31, 2012.