As a result, people who have multiple myeloma are especially susceptible to infections. Pieces of the abnormal antibodies frequently end up in the kidneys, damaging them and sometimes causing kidney failure. Abnormal antibody pieces in the urine are called Bence Jones proteins. Multiple myeloma often causes bone pain, especially in the spine or ribs, and weakens bones, which may fracture easily. Anemia results when the abnormal plasma cells crowd out the normal cells that produce red blood cells in the bone marrow.
Bacterial infections result because abnormal antibodies are ineffective against infections.
Inadequate flow of blood to the brain can result in neurologic symptoms, such as confusion, visual problems, and headaches. Several blood tests may help a doctor diagnose this disorder. A complete blood cell count may detect anemia and abnormal red blood cells. However, the key diagnostic tests are serum protein electrophoresis and immunoelectrophoresis, blood tests that detect and identify the abnormal antibody that's the telltale sign of multiple myeloma. This antibody is found in about 85 percent of the people who have this disorder.