Symptoms and diagnosis of multiple myeloma

The most specific symptoms of multiple myeloma are pain and fragility at the bone level. The symptoms of fatigue, anemia, calcium elevation, or renal insufficiency (called CRAB criteria, acronym for Calcemia-Renal-Anemia-Bone) are also indicative of this cancer. The diagnosis is then confirmed by protein electrophoresis (separation of proteins according to their electrical charge), which aims to search for a peak of monoclonal immunoglobin, highly suggestive of myeloma. This is supplemented by serum immunofixation to determine the type of immunoglobulin secreted by the plasma cells, by a light chain assay (to look for the presence of a monoclonal light chain), and by a Bence Jones proteinuria test (in the urine). In the case of light chain myelomas, the monoclonal peak does not appear. 

Conversely, a peak in monoclonal immunoglobin can be discovered during protein electrophoresis performed during a systematic review, and it does not mean that the patient suffers from myeloma. This peak can be isolated, can be associated with a disease, or can precede its appearance. 

The definitive diagnosis is established by bone marrow puncture, with analysis of its composition, called myelogram. If this analysis reveals that the marrow is invaded by more than 10% of dystrophic plasma cells, the diagnosis of myeloma is established. 

A genetic study (called FISH analysis) is also sometimes carried out from a bone marrow sample, and it aims to determine the genetic characteristics of a good or bad prognosis in the diseased plasma cells. 

Finally, additional imaging examinations, such as a positron emission tomography (PET scanner) or a pelvic-spinal MRI, may be prescribed to look for possible bone damage.