Acute kidney failure occurs when your kidneys suddenly become unable to filter waste products from your blood. When your kidneys lose their filtering ability, dangerous levels of wastes may accumulate, and your blood's chemical makeup may get out of balance.
Acute kidney failure can be fatal and requires intensive treatment. However, acute kidney failure may be reversible. If you're otherwise in good health, you may recover normal or nearly normal kidney function.
Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as either acute kidney failure, which develops rapidly and may resolve; and chronic kidney failure, which develops slowly and can often be irreversible. Symptoms may include leg swelling, feeling tired, vomiting, loss of appetite, and confusion. Complications of acute and chronic failure include uremia, high blood potassium, and volume overload. Complications of chronic failure also include heart disease, high blood pressure, and anemia.
Causes of acute kidney failure include low blood pressure, blockage of the urinary tract, certain medications, muscle breakdown, and hemolytic uremic syndrome. Causes of chronic kidney failure include diabetes, high blood pressure, nephrotic syndrome, and polycystic kidney disease. Diagnosis of acute failure is often based on a combination of factors such as decreased urine production or increased serum creatinine. Diagnosis of chronic failure is based on a glomerular filtration rate (GFR) of less than 15 or the need for renal replacement therapy. It is also equivalent to stage 5 chronic kidney disease.
Treatment of acute failure depends on the underlying cause. Treatment of chronic failure may include hemodialysis, peritoneal dialysis, or a kidney transplant. Hemodialysis uses a machine to filter the blood outside the body. In peritoneal dialysis specific fluid is placed into the abdominal cavity and then drained, with this process being repeated multiple times per day. Kidney transplantation involves surgically placing a kidney from someone else and then taking immunosuppressant medication to prevent rejection. Other recommended measures from chronic disease include staying active and specific dietary changes. Depression is also common among patients with kidney failure, and is associated with poor outcomes including higher risk of kidney function decline, hospitalization, and death. A recent PCORI-funded study of patients with kidney failure receiving outpatient hemodialysis found similar effectiveness between nonpharmacological and pharmacological treatments for depression.
In the United States acute failure affects about 3 per 1,000 people a year. Chronic failure affects about 1 in 1,000 people with 3 per 10,000 people newly developing the condition each year. Acute failure is often reversible while chronic failure often is not. With appropriate treatment many with chronic disease can continue working.
Kidney failure can be divided into two categories: acute kidney failure or chronic kidney failure. The type of renal failure is differentiated by the trend in the serum creatinine; other factors that may help differentiate acute kidney failure from chronic kidney failure include anemia and the kidney size on sonography as chronic kidney disease generally leads to anemia and small kidney size.
Acute kidney injury (AKI), previously called acute renal failure (ARF), is a rapidly progressive loss of renal function, generally characterized by oliguria (decreased urine production, quantified as less than 400 mL per day in adults, less than 0.5 mL/kg/h in children or less than 1 mL/kg/h in infants); and fluid and electrolyte imbalance. AKI can result from a variety of causes, generally classified as prerenal, intrinsic, and postrenal. Many people diagnosed with paraquat intoxication experience AKI, sometimes requiring hemodialysis. The underlying cause must be identified and treated to arrest the progress, and dialysis may be necessary to bridge the time gap required for treating these fundamental causes.
Acute kidney injuries can be present on top of chronic kidney disease, a condition called acute-on-chronic kidney failure (AoCRF). The acute part of AoCRF may be reversible, and the goal of treatment, as with AKI, is to return the person to baseline kidney function, typically measured by serum creatinine. Like AKI, AoCRF can be difficult to distinguish from chronic kidney disease if the person has not been monitored by a physician and no baseline (i.e., past) blood work is available for comparison.
Symptoms can vary from person to person. Someone in early stage kidney disease may not feel sick or notice symptoms as they occur. When the kidneys fail to filter properly, waste accumulates in the blood and the body, a condition called azotemia. Very low levels of azotaemia may produce few, if any, symptoms. If the disease progresses, symptoms become noticeable (if the failure is of sufficient degree to cause symptoms). Kidney failure accompanied by noticeable symptoms is termed uraemia.
Drug overdoses, accidental or from chemical overloads of drugs such as antibiotics or chemotherapy, along with bee stings may also cause the onset of acute kidney injury. Unlike chronic kidney disease, however, the kidneys can often recover from acute kidney injury, allowing the person with AKI to resume a normal life. People with acute kidney injury require supportive treatment until their kidneys recover function, and they often remain at increased risk of developing future kidney failure.
Chronic kidney failure has numerous causes. The most common causes of chronic failure are diabetes mellitus and long-term, uncontrolled hypertension. Polycystic kidney disease is another well-known cause of chronic failure. The majority of people affected with polycystic kidney disease have a family history of the disease. Other genetic illnesses cause kidney failure, as well.
The APOL1 gene has been proposed as a major genetic risk locus for a spectrum of nondiabetic renal failure in individuals of African origin, these include HIV-associated nephropathy (HIVAN), primary nonmonogenic forms of focal segmental glomerulosclerosis, and hypertension affiliated chronic kidney disease not attributed to other etiologies. Two western African variants in APOL1 have been shown to be associated with end stage kidney disease in African Americans and Hispanic Americans.
Chronic kidney failure is measured in five stages, which are calculated using the person's GFR, or glomerular filtration rate. Stage 1 CKD is mildly diminished renal function, with few overt symptoms. Stages 2 and 3 need increasing levels of supportive care from their medical providers to slow and treat their renal dysfunction. People with stage 4 and 5 kidney failure usually require preparation towards active treatment in order to survive. Stage 5 CKD is considered a severe illness and requires some form of renal replacement therapy (dialysis) or kidney transplant whenever feasible.
Before the advancement of modern medicine, renal failure was often referred to as uremic poisoning. Uremia was the term for the contamination of the blood with urea. It is the presence of an excessive amount of urea in blood. Starting around 1847, this included reduced urine output, which was thought to be caused by the urine mixing with the blood instead of being voided through the urethra. The term uremia is now used for the illness accompanying kidney failure.
Those with end stage renal failure who undergo haemodialysis have higher risk of spontaneous intra-abdominal bleeding than the general population (21.2%) and non-occlusive mesenteric ischemia (18.1%). Meanwhile, those undergoing peritoneal dialysis have a higher chance of developing peritonitis and gastrointestinal perforation. However, the rate of acute pancreatitis does not differ from the general population.
The treatment of acute kidney injury depends on the cause. The treatment of chronic kidney failure may include renal replacement therapy: hemodialysis, peritoneal dialysis, or kidney transplant.
Sometimes kidneys are no longer able to filter and clean blood. This can cause unsafe levels of waste products to build up. This is known as kidney (or renal) failure. Unless it is treated, this can cause death.
Before kidney failure occurs, patients have "chronic kidney disease" (CKD). Kidney (renal) failure is when kidneys don't work as well as they should, to the point where kidney replacement is required. Kidney replacement can be accomplished by different kinds of dialysis or by kidney transplant. The term "kidney failure" covers a lot of problems. These problems can result in kidney failure:
The symptoms of CKD are often quite mild; people may have significantly reduced kidney function and not be aware of it. The symptoms of kidney failure can differ based on how bad the kidney failure is, how quickly it is getting worse, and what is causing it.
Kidney failure is most often found when the creatinine level is high, indicating that kidney function is reduced. Creatinine is a molecule made by your muscles. A normal kidney will remove creatinine from the blood stream and get rid of it in urine. More creatinine in the blood is a sign that the kidneys aren't cleaning the blood as well as they should. This test can spot something is wrong before a patient with kidney failure feels sick.
With CKD, treating the cause (such as high blood pressure and/or high blood sugar) can slow the disease. The goal is to prevent CKD from turning into advanced kidney disease, or end stage kidney disease (ESKD, formerly known as end stage renal disease, ESRD). 041b061a72