by Dr. C.H. Weaver M.D.
Acute renal failure is a malfunction of the kidneys so that they are unable to perform their vital functions, one of the most important of which is filtering out waste. Some cancer treatments cause damage to the kidneys that can result in acute kidney failure. Kidney damage is usually reversible, if it is carefully managed to control the life-threatening complications. Once the drug or drugs that are causing the kidney damage are stopped, treatment focuses on preventing the excess accumulation of fluid and waste while allowing the kidneys to heal.
What is acute renal failure
Acute renal failure is a malfunction of the kidneys so that they are unable to perform the vital function of filtering out waste from the blood. Acute renal failure may be caused by decreased blood supply to the kidneys from drugs or infection, damage to the kidneys, or by blockage in the urinary system. The most common cause of acute renal failure in cancer patients is damage to the cells in the kidney.
The kidneys are fist-sized organs located in your lower back, near your spine. Their chief functions are to filter out waste products and regulate electrolytes and water levels. When the body breaks down protein from the diet for energy or building tissues, it produces a waste product called urea. Urea circulates in the blood until it is filtered out by the kidneys and excreted in the urine. When the kidneys are not functioning properly, filtration is reduced and urea builds up in the blood. Also the balance of electrolytes and water cannot be adequately regulated, resulting in a buildup of potassium, sodium and fluid.
Kidney damage may also result in increased excretion of protein in the urine. Protein is an important component in our blood that carries food, hormones, and many other things through the body. Under normal conditions, blood proteins do not pass through the kidneys into the urine because they are too big. If you have kidney damage, protein may pass into your urine. Protein in the urine may be a sign of permanent kidney damage, or failure.
What causes kidney damage
Some chemotherapy drugs and biological therapies can cause kidney damage. Chemotherapy causes renal dysfunction by damaging the blood vessels or structures of the kidneys. The chemotherapy drugs that are most likely cause kidney damage are listed in table 1.
Table 1 Chemotherapy drugs that have been reported to cause kidney damage in 10% or more of patients
What are the symptoms of kidney damage
You may not have any symptoms of kidney damage. However, you should notify your doctor if you exhibit any of the following:
- Decrease in amount of urine or frequency
- Pain or urgency with urination
- Dark urine
- Blood in your urine
- Muscle weakness
- Swelling in your feet or ankles
- Nausea or vomiting
- Confusion, seizure
Notify your doctor immediately if your urine output decreases or stops.
How is kidney damage diagnosed
Blood levels of two products of normal body function, blood urea nitrogen and creatinine, are used to diagnose kidney problems.
Blood urea nitrogen (BUN): The waste product from the breakdown of protein is called urea. Urea circulates in the blood until it is filtered out by the kidneys and excreted in the urine. If the kidneys are not functioning properly, there will be excess urea in the bloodstream. Under normal conditions, BUN levels range from 10-25 mg/dL (milligrams per deciliter) of blood.
Creatinine: Some of the energy for your muscles is derived from burning a substance called creatine. Creatinine is the waste product left after the breakdown of creatine. The kidneys are normally able to filter out large amounts of creatinine on a daily basis. However, when your kidneys are not functioning properly, your creatinine levels will increase. Under normal conditions, creatinine levels range from 0.7-1.4 mg/dL(milligrams per deciliter) of blood.
How is kidney damage treated
Kidney damage is usually reversible, if it is carefully managed to control the life-threatening complications. Once the drug or drugs that are causing the kidney damage are stopped, treatment focuses on preventing the excess accumulation of fluids and wastes while allowing the kidneys to heal. This may be achieved in several ways, including diuretics, sodium polystyrene sulfonate, diet modification, dialysis or drugs.
Diuretics: Your doctor may prescribe a diuretic to increase the amount of water you excrete in the urine. A commonly used diuretic is furosemide (Lasix®).
Sodium polystyrene sulfonate: This medication helps lower the amount of potassium in your blood by binding with the potassium in your stomach or gut so that you excrete it. This medication is administered by mouth or in an enema.
Diet modification: Your doctor may recommend that you restrict substances that are normally excreted by the kidney. This may include foods high in protein, sodium (salt) and potassium.
Dialysis: Dialysis is the use of a machine to remove excess waste and fluid. Your blood is routed through the dialysis machine then back into your body. Dialysis is not necessary for every patient, but may be lifesaving, particularly if you have very high levels of potassium in your blood.
Drugs: Amifostine (Ethyol®), sodium thiosulfate, and diethyldithiocarbamate may help prevent or reduce the kidney toxicity associated with cisplatin
How can kidney damage be prevented
The best measure for preventing kidney damage is to avoid treatments that cause it. Under certain circumstances, your doctor may also apply the following approaches:
Urinary alkalization and hydration: Urinary alkalization and increased hydration provides protection against kidney damage caused by methotrexate.
Amifostine (Ethyol®): Clinical trials have shown that amifostine protects against kidney toxicity related to cisplatin chemotherapy.
 Kintzel PE. Anticancer drug-induced kidney disorders. Drug Saf. 2001 Jan; 24(1): 19-38.
 Heidenreich A, Marx FJ, Peters HJ. Amifostine as protective agent in cisplatin-based chemotherapy of advanced bladder cancer. Urologe A 1999:38:586-91 (Abstract).