The word "chemotherapy" may evoke fear in patients, many of whom are concerned about side effects. Most people are familiar with the traditional symptoms associated with chemotherapy, such as nausea and vomiting. But chemotherapy can affect every organ system in the body, including the renal system, which includes the kidneys and bladder.
Nephrotoxicity
Nephrotoxicity occurs when the kidneys are damaged by a toxin present in the body. While chemotherapy kills cancer cells, it also can act as a toxin to healthy cells. Some chemotherapy drugs that may damage the kidneys are cisplatin, carboplatin, mitomycin, methotrexate and carmustine.
When the kidneys become damaged by chemotherapy, they're unable to rid the body of excess urine and wastes. The patient may experience weight gain from fluid retention, or hematuria, which is blood in the urine. If nephrotoxicity persists, changes in mental status and level of consciousness may occur.
Blood tests that can indicate nephrotoxicity include serum creatinine and BUN, or blood urea nitrogen. Urea is a waste product found in the bloodstream, and creatinine is a byproduct of energy production. Elevated levels of either may indicate problems in the renal system linked to chemotherapy.
Hemorrhagic Cystitis
The body breaks down chemotherapy drugs and eliminates them through the bladder. When certain chemotherapy drugs, including cyclophasphamide and ifosfamide, are broken down for elimination, they irritate the lining of the bladder. This irritation can result in bleeding during urination, which may be mild or severe and may occur at any point in the treatment schedule. Along with bleeding, other symptoms of hemorrhagic cystitis include frequent urination, burning during urination, loss of bladder control and lower abdominal discomfort.
Patients taking chemotherapy drugs that may damage the renal system often are also given a chemoprotective agent called mesna. As the National Cancer Institute notes, mesna works by binding to and inactivating the irritating substances produced by chemotherapy. This reduces the ability of the chemotherapy to irritate the bladder and kidneys.
Urinary Tract Infection
If hemorrhagic cystitis is not treated quickly, the bladder can become infected. Signs of bladder or urinary tract infection include pain or burning with urination, urine with a foul smell and cloudy color, lower abdominal discomfort, fever and chills. Infection must be treated quickly in chemotherapy patients so it does not become life-threatening.
Patients can help prevent renal system side effects by drinking up to three liters of clear fluids daily, with a doctor's permission, and urinating often throughout the day and night. A doctor should be contacted immediately if signs of renal problems are detected.
