Acute impaired renal function can be caused by a temporary reduction in blood flow or obstruction of urine in the kidneys, according to American Family Physician. An infection or heart attack may reduce blood flow, and kidney stones can block the flow of urine. Chronic impaired renal function is often due to diabetes or untreated high blood pressure. These chronic conditions also damage blood flow to the kidneys and impair renal function, says the National Kidney Foundation.
Acute kidney failure can be reversible, according to Mayo Clinic. First, the cause of the kidney failure, such as infection, obstruction or dehydration, must be treated. Fluids, medications and electrolytes may be given intravenously to help the body keep chemicals and electrolytes balanced while the kidneys heal. In some cases, temporary dialysis is needed. During dialysis, a machine filters toxins and waste from the blood, a job normally done by the kidneys. If the kidney damage is reversible, dialysis can be discontinued after the injury to the kidneys heals.
Chronic kidney disease is due to continual damage to the kidneys over time. Older people, African-American, Asian or Hispanic individuals, and those with a family history of kidney disease are also at increased risk of chronic kidney failure, reports the American Kidney Fund. If the kidneys become so badly damaged that they can no longer function, a patient needs regular dialysis treatments or a kidney transplant.