Multiple myeloma (MM) is a type of blood cancer that affects white blood cells called plasma cells. These cells help to fight infection. In MM, the abnormal plasma cells produce abnormal proteins that can bind to other proteins in the kidneys. This can result in kidney damage.
Kidney failure is a common complication of MM. Symptoms may include appetite loss, weight loss, and urinary tract infections (UTIs). The treatment for MM and kidney failure involves treating the underlying MM and supporting the kidney function.
This article describes the link between MM and kidney failure, how MM affects the kidneys, and the risk for developing MM-related kidney failure. We also outline how doctors diagnose and treat MM and kidney failure and the outlook for people living with these conditions.
The kidneys carry out a number of vital functions, including:
- producing hormones
- balancing electrolytes and body fluids
- excreting waste
In MM, the bone marrow produces abnormal plasma cells. These abnormal cells make abnormal proteins, which accumulate in the blood. As the abnormal proteins pass through the kidneys, they can bind with other proteins and affect kidney function. When this occurs, a person may experience symptoms of kidney disease, which include:
- insomnia or difficulty sleeping
- reduced energy levels
- poor concentration
- appetite loss
- excessive urination
- frothy urine or blood in the urine
- dry, itchy skin
- puffy eyes
- swollen feet and ankles
- muscle cramps
Multiple myeloma can affect multiple parts of the kidney, including:
- the filters or “glomeruli,” which filter the blood
- the pipes or “tubules,” which allow urine and waste to exit the body
- the kidney itself
In MM, the abnormal plasma cells make abnormal proteins. These abnormal proteins travel through the bloodstream, through the glomeruli, and into the tubules in the kidneys. Once inside the tubules, the abnormal proteins can attach to another type of protein normally present in urine, called “Tamm-Horsfall” protein. The two proteins join together to form a “cast” that is too big to pass through the tubules. This means the proteins are unable to exit the kidneys in the form of urine.
Casts not only block the tubules, they also cause inflammation of the kidneys. Kidney failure that occurs due to these casts is called “cast nephropathy” or “myeloma kidney.”
People living with MM may develop kidney failure as a result of:
- kidney damage due to high levels of calcium in the blood
- kidney damage due to toxic levels of certain proteins
- infections due to the effect of MM on the immune system or due to MM treatments
- some prescription drugs
- some non-prescription drugs or vitamins that the damaged kidneys are unable to process
A number of risk factors may increase the likelihood of kidney failure in people living with MM. These include:
- older age
- undergoing chemotherapy treatment for MM
- receiving an MM diagnosis in the later stages of the disease
Certain preexisting medical conditions can also increase the likelihood of kidney failure in MM. These include:
- other preexisting kidney conditions
- high blood pressure
People with early stage kidney disease may not experience any symptoms.
Anyone who experiences symptoms of myeloma kidney should see their doctor for a blood test to check their kidney function. Symptoms of myeloma kidney may
- loss of appetite
- unexplained weight loss
- bone pain
People who have MM with kidney failure will likely require treatment from a range of medical professionals, including:
- an oncologist, who is a doctor specializing in cancer
- a hematologist, who is a doctor specializing in conditions of the blood and blood-forming tissues
The treatment for myeloma kidney usually involves treating the MM. Treatment will vary on a case-by-case basis, and a person will work with the healthcare professionals to find the best treatment plan for them. Some possible treatment options include:
- chemotherapy or radiation therapy to help reduce abnormal plasma cell numbers
- stem cell transplantation to help boost numbers of normal plasma cells
- plasmapheresis, which is a procedure to remove blood plasma and replace it with plasma from a donor
- immunotherapy, which involves using drugs to artificially stimulate the immune system into fighting cancer
- drugs to help fight infection
- pain-relieving medications
Treatment for myeloma kidney will also involve supporting the kidneys and alleviating pain. This may include the following:
- drugs to help fight infection
- pain-relieving medications
- intravenous fluids, if dehydration is present
To diagnose MM, a doctor will perform a physical examination and take a full medical history. If the doctor suspects MM, they may order the
- blood tests
- urine tests
- bone marrow aspiration and biopsy tests
- imaging tests to assess the bones, which may include X-rays or magnetic resonance imaging (MRI) scans
If a person has already received a diagnosis of MM and is experiencing symptoms of kidney disease, their doctor will request blood and urine tests to assess their kidney function.
According to the Multiple Myeloma Research Foundation (MMRF), the most recent survival statistics available for MM cover 2010–2016. During this period, the 5-year relative survival for MM was 53.9%, meaning that around 54 in every 100 people living with MM were alive 5 years following their diagnosis. The MMRF notes that survival rates for MM are improving, mainly due to advances in treatment.
The outlook for a person who has developed MM with kidney involvement depends on a number of factors, including:
- the person’s age
- the stage of MM
- the type of treatment the person is receiving for MM, and whether the disease is responding to the treatment
- the extent of kidney damage
A person who has MM with kidney involvement should talk with their doctor or healthcare specialist team about their treatment options and individual outlook.
Multiple myeloma (MM) is a type of blood cancer that affects white blood cells called plasma cells. In MM, the abnormal plasma cells produce abnormal proteins. These abnormal proteins can bind with other proteins in the kidneys to form large casts. The casts can block tubes within the kidneys, leading to kidney failure. Medical professionals refer to this as myeloma kidney.
People who have a diagnosis of MM should be aware that kidney failure is a possible complication of the disease. Kidney disease often does not cause symptoms until it has reached an advanced stage. Anyone who is concerned about myeloma kidney should contact their doctor for a diagnosis.
The treatment for myeloma kidney involves treatment for MM as well as treatment to support the kidneys. The treatment approach will vary on a case-by-case basis. A person should talk with their doctor or healthcare specialist team about their individual treatment options and outlook.