Myeloma & Kidney Disease: Getting the Basics

This particular cancer can cause kidneys to shut down

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WHAT IS MULTIPLE MYELOMA?

Like any cancer, myeloma is also a case of uncontrolled cell growth/division, often at the cost of other cells. Myeloma is cancer of something called the "plasma cells".  Plasma cells are a specific type of mature white blood cells (called lymphocytes) that are found in the bone marrow. Their function is to make something called "antibodies" to fight infections, also known as immunoglobulins.

When a myeloma develops, plasma cells begin to divide unhindered (at the cost of other necessary cells in the bone marrow). Blood tests will therefore usually show high levels of abnormal antibodies/immunoglobulins produced by this mass of cells.

HOW DOES MULTIPLE MYELOMA DAMAGE THE KIDNEYS?

Once the above-mentioned abnormal proteins, immunoglobulins, are produced they start to circulate in the blood and begin to be filtered by the kidneys.  However, the abnormally high levels can overwhelm the kidneys' ability to excrete these proteins effectively.  Therefore, these immunoglobulins can literally clog the kidneys' drainage system causing a phenomenon called cast nephropathy. Beyond this physical phenomenon, some immunoglobulins are also known to be directly toxic to the kidney cells and could therefore cause kidney disease and kidney failure to develop. Kidney disease that develops because of multiple myeloma is referred to as myeloma kidney.

Another entity that can develop in the kidney in the setting of myeloma, is something called amyloidosis.  This is due to an abnormal protein deposition in the kidney which hurts the kidneys' filter. I have discussed this entity in detail here.

WHAT ARE THE SYMPTOMS AND SIGNS OF MYELOMA KIDNEY?

Patients can be expected to have the typical, non-specific symptoms and signs of kidney disease.

These could include vague symptoms like fatigue, shortness of breath, etc. Appetite may be reduced. Bone pain might be reported by the myeloma kidney patient as well.  I have covered symptoms of kidney disease and kidney failure in further detail here.

More specifically, lab tests could reveal the following signs:

HOW CAN YOU CONFIRM THE DIAGNOSIS OF MYELOMA KIDNEY?

The above-mentioned signs and symptoms will aid in the diagnosis of myeloma kidney.  However, in order to confirm the diagnosis, more specific tests like protein electrophoresis and immune fixation will be necessary.  If the clinical picture is highly suggestive and blood tests indicate the presence of abnormally high levels of immunoglobulin, a presumptive diagnosis of myeloma kidney might be made.

 However, in order to make a definite diagnosis of myeloma kidney, the test needed would be a kidney biopsy (which entails taking a small piece of the kidney tissue and seeing it under a microscope).  Details of the procedure here.

CAN MYELOMA KIDNEY BE TREATED?

Your nephrologist and oncologist will likely suggest multiple options to treat myeloma kidney.  It goes without saying that myeloma (which is the underlying reason for kidney failure in this case) needs to be treated aggressively.  Chemotherapy with medications like bortezomib might be needed to stop further production of abnormal immunoglobulins.  In order to remove the existing immunoglobulins already present in the blood,  your physician might recommend a treatment called plasmapheresis, although the evidence for whether it works or not is pretty mixed.

Other concurrent problems like high calcium will need separate treatment.  If complete kidney failure develops, with signs of uremia developing, renal replacement therapy with dialysis might be necessary.

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