The most common symptom of multiple myeloma is fatigue, found in 70 percent of patients at diagnosis. When myeloma cells replace oxygen-carrying red blood cells in the bone marrow, anemia can result, causing tiredness or fatigue.
Another common myeloma symptom is pain in the back, ribs, or other bones, which may be caused by the large number of myeloma cells in bone marrow. The pain, which can be severe, may occur months before a diagnosis is made. Unexplained bone fractures may also be a sign of myeloma.
Myeloma can cause osteoporosis, or thinning and weakening of the bones. X-rays of the bones sometimes appear to show holes called lytic lesions. These are not actually holes, but weakened areas of bone associated with concentrations of myeloma cells.
Calcium from affected bones may sometimes dissolve into the blood, causing fatigue, constipation, loss of appetite and excessive thirst and urination. This high blood-calcium level, known as hypercalcemia, occurs in about 25 percent of myeloma patients.
Myeloma cells often produce an unusual amount of monoclonal (M) protein. This protein may be called Bence Jones protein when found in urine or an M-spike when found in blood. Whether this protein is found in the blood, urine or both varies among patients.
Sometimes, monoclonal proteins are deposited in the kidneys and prevent normal filtering of the blood's waste products. As a result, about one-fourth of myeloma patients have kidney damage at diagnosis. High levels of M protein may also cause nausea, anemia and fatigue.