Symptoms and Signs
Many patients with multiple myeloma show no symptoms for many years. Eventually, most patients develop some evidence of the disease related to weakened bones (bone pain), decreased numbers of red or white blood cells (anemia, infections), and kidney disease or failure. As bones weaken, soft spots and fractures may develop. Destruction of the bone frequently increases the level of calcium in the blood, leading to symptoms of hypercalcemia such as loss of appetite, nausea, thirst, fatigue, constipation, and confusion. Decreases in the number of normal WBCs, RBCs, and platelets often result in recurrent infections, anemia, bleeding, and bruising. Bence Jones proteins can lodge in the kidneys and may permanently damage them. In some cases, an increase in the thickness (viscosity) of the blood may lead to headaches.
Multiple myeloma is relatively uncommon. The American Cancer Society estimates that about 20,000 new cases of multiple myeloma are diagnosed each year in the U.S. and that a little over 10,000 people with multiple myeloma die. The cause of multiple myeloma is not yet known. The risk of developing it increases with age, with the majority of cases being diagnosed in patients 60 years or older. While there are a few families who have a higher incidence of multiple myeloma, most patients will not have any affected relatives. It is thought that the disease may be associated with a decrease in immune system function, occupational exposure to toxins and/or solvents, genetic factors, certain viruses, and radiation exposure.