Myeloma and the kidney
In this article, we will describe what is myeloma, how it affects the kidneys, and what treatment is available.
Myeloma is a type of blood cancer arising from ‘plasma cells’ that are normally found in the bone marrow. Plasma cells are a type of white blood cell which form part of the immune system.
It accounts for 15% of blood cancers and 2% of cancers generally. The average age of onset is 65 to 70 years. It is more common black in people, less common in Asian people ethnic group, compared with white people.
50% of patients at diagnosis have kidney involvement, and 20% develop AKI or CKD, or both. Kidney involvement is associated with higher mortality.
What is myeloma?
Normal plasma cells produce different types of antibodies (which are a type of protein) to help fight infection.
In myeloma, the plasma cells in the bone marrow (where blood cells are made) become cancerous (sometimes called malignant) and release a large amount of a single type of antibody, known as a ‘paraprotein’, which has no useful function. It is often through the measurement of paraprotein that myeloma is diagnosed and monitored.
For the bone marrow to make blood cells, it contains ‘stem cells’. Stem cells are amongst the most important cells in our body. They can develop into many cell types which are necessary for us to function, including blood cells.
In myeloma, the abnormal plasma cells multiply in high numbers and overcrowd the stem cells in healthy bone marrow tissue, leading to decreased production of healthy blood cells.
This leads to impaired immune function, as well as anaemia (lack of red cells, another type of blood cell), and a greater likelihood of bruising and bleeding (lack of platelets, another blood cell).
The abnormal plasma cells produce substances which activate (strengthen) ‘bone-eating’ cells (osteoclasts), leading to bone break down. This can lead to bone pain and significantly increased calcium levels (hypercalcaemia).
Myeloma is sometimes called ‘multiple myeloma’ because it affects more than one part of your body.
How can myeloma affect my kidneys?
Myeloma cells also produce incomplete antibodies (called ‘light chains’), which are excreted through the kidneys. These light chains – alongside raised calcium levels, infection and dehydration – damage kidney tissue, through blockage, inflammation, and fibrosis (scarring).
This is sometimes called ‘cast nephropathy’. The casts are casts of light chains combined with proteins forming many ‘mini-plugs’ that disrupt urine flow in the kidney.
Myeloma cast nephropathy in a kidney biopsy, with a typical ‘fractured cast’ in a tubule on the right. Note Courtesy of Renal Fellow Network.
It can lead to AKI or CKD, or both. Some patients require long-term dialysis. In a few of those, it may be possible to do a kidney transplant.
How will myeloma affecting my kidneys be treated?
Fortunately, in many patients, treating the myeloma with chemotherapy is usually enough to prevent further kidney damage. It is important this treatment is started ASAP, to prevent more kidney damage.
After chemotherapy puts you in ‘remission’ (i.e. myeloma has ‘gone away’), a stem cell transplant is often carried out. This is also done when myeloma affects the kidneys. The new stem cells are grown from your own ones. It also called an autologous transplant or auto transplant.
Here is more information from the Cancer Research UK website on stem cell transplants in myeloma.
What you can do – lifestyle management may help your kidneys
This includes:
1. Maintaining a healthy blood pressure
- A healthy (low) blood pressure is essential for maintaining your kidney function
- Regular (gentle) exercise alongside a nutritious, healthy diet and a decrease in saturated fat consumption, may aid blood pressure control.
2. Not smoking
3. Staying well hydrated
- Dehydration can significantly worsen kidney function in myeloma. Maintaining a good fluid intake (e.g. 2-3L a day) is important
- HOWEVER, this would not be the case if undergoing dialysis, where you may be asked to follow a fluid restriction. If you have any questions regarding fluid intake whilst on dialysis, please contact your doctor.
Note. You can access more CKDExplained information on dialysis and kidney transplantation here.
Summary
Thank you for reading our article on myeloma and the kidney. We have described what is myeloma, how it affects the kidneys, and what treatment is available. We hope this was helpful!
Other resources
Here is more information on myeloma again on the Cancer Research UK website.
Myeloma and the kidney (Myeloma UK)
Review article: Vakiti, 2022
Last Reviewed on 17 May 2024