What is Multiple Myeloma?
Multiple myeloma is a type of blood cancer. It affects plasma cells that produce antibodies to fight infections and diseases.
Healthy plasma cells are found inside bones in the bone marrow. Abnormal plasma cells can grow out of control and form tumors in the bones.
A single plasma cell tumor is known as an isolated plasmacytoma. A person who has more than one plasmacytoma has multiple myeloma.
The antibodies made by plasma cells are special proteins that circulate throughout the body in the blood stream. Multiple myeloma causes affected plasma cells to create large numbers of abnormal proteins that cannot be used by the body.
Multiple myeloma can also damage bone tissue and cause it to break down or dissolve. Hypercalcemia is the condition that results when dissolved bone results in abnormally high amounts of calcium in the blood.
How Does Multiple Myeloma Affect the Kidneys?
Kidney failure is a common complication of multiple myeloma that affects approximately 20 percent of patients.
The kidneys are organs in the abdomen that act as filters to clean waste products out of the blood stream. This waste is passed out of the body as urine.
Multiple myeloma can damage the kidneys’ ability to filter waste.
Kidney failure results when the kidneys are no longer able to function and they shut down. Kidney failure must be treated with dialysis in which machines take over the work of the kidneys to remove waste from the body.
If multiple myeloma results in excess calcium in the blood, the kidneys can be damaged due to overwork as they try to remove the extra calcium. This can cause permanent kidney damage.
Multiple myeloma can also damage the tubules inside the kidneys that allow blood to flow through the kidney to be filtered. Abnormal proteins created by cancerous plasma cells travel through the blood to the kidneys.
Normal proteins are small enough to pass through the tubules without causing damage. But chains of abnormal proteins can sometimes link up with other proteins in the kidney that are a normal part of urine.
When this happens the combined proteins, which are known as casts, are too large to fit through the tubules. This causes a blockage that can lead to kidney damage.
Casts of combined proteins can also cause inflammation or swelling in the tissue of the kidney, causing further damage.
When the kidneys are damaged, lab tests can show increased levels of creatinine or abnormal amounts of protein in the urine.
Kidney damage caused by multiple myeloma is often detected as a side-result of other tests for symptoms of multiple myeloma, such as bone pain, broken bones, fatigue and infections.
Up to 50 percent of multiple myeloma patients already have kidney damage at the time their cancer is first diagnosed.
How Can You Protect Your Kidneys?
If you have multiple myeloma, you can help protect your kidneys by making sure you are always well-hydrated. Drink ample amounts of plain water to help your kidneys flush out harmful substances including excess proteins and calcium.
If you have multiple myeloma and your kidneys have been damaged, your doctor will probably instruct you not to take NSAIDs, including ibuprofen and naproxen. These pain relievers are hard on the kidneys.
Your doctor may also avoid using IV contrast dye for CT scans as well as some aggressive or high-dose chemotherapy treatments for your cancer. These chemicals can be hard for the kidneys to remove and can cause other health concerns if they build up in the blood.
If you have high levels of calcium in your blood, your doctor may prescribe treatments to lower your calcium levels.
Treatment for kidney damage caused by multiple myeloma hinges on controlling the cancer. Talk to your health care provider if you have questions about multiple myeloma or kidney disease.
Sources:
American Cancer Society. What is multiple myeloma? Web. December 17, 2014.
http://www.cancer.org/cancer/multiplemyeloma/detailedguide/multiple-myel...
UNC Health Care: Kidney Center. Myeloma Kidney. Web. December 17, 2014.
http://www.unckidneycenter.org/kidneyhealthlibrary/myeloma.html
International Myeloma Foundation. Protecting Kidney Function in Multiple Myeloma. Ann McNeill, RN, MSN, APN. Web. December 17, 2014.
http://myeloma.org/MtEntryPage.action?source=/imf_blogs/oh_nurse/2011/02...
The Myeloma Beacon. Kidney Failure in Multiple Myeloma Patients – Part 1: Overview. Kristen O’Connor. Web. December 17, 2014.
http://www.myelomabeacon.com/news/2009/06/26/an-overview-of-kidney-failu...
Reviewed December 18, 2014
by Michele Blacksberg RN
Edited by Jody Smith