Multiple myeloma is a type of cancer that affects the plasma cells (a type of white blood cell) in bone marrow. Normal plasma cells make antibodies to fight off infection; however, in those with multiple myeloma, plasma cells form tumors in bone marrow, which cause excess growth of abnormal plasma cells that cause blood problems and interfere with immune function and bone health. Symptoms of multiple myeloma may be mild at first, worsening as the disease progresses.
General Symptoms
Pain caused by plasma cell tumors in the bone is a common symptom of multiple myeloma. This pain may be particularly likely to develop in the back, ribs, hips and skull, according to the Mayo Clinic. Loss of bone density may also occur as a result of bone marrow tumors, thus weakening bones and increasing the likelihood of fractures. Bone weakening is associated with the release of calcium from bones into the bloodstream. Abnormally high levels of calcium in the blood can cause a number of bothersome and potentially serious symptoms, including constipation, excessive thirst and urination, nausea, loss of appetite and confusion. Additional adverse effects on the heart, kidneys and brain or weakness or numbness in the legs may also occur.
Kidney Problems
Kidney failure is a common symptom that occurs in those with multiple myeloma, according to the Mayo Clinic. Problems with kidney function often arise because the proteins produced by the abnormal plasma cells in bone marrow interfere with the kidney's ability to filter waste products from the blood. The Merck Manual of Health and Aging (MMHA) adds that cancerous cells can cause the body to produce too much uric acid, a substance usually excreted in the urine. Too much uric acid can cause kidney stones, a solid mass of crystals that cause pain and bleeding as it moves through the urinary tract. Deposits of proteins in the kidneys (or other organs) can also cause amyloidosis, a rare disease caused by the buildup of abnormal proteins that can lead to symptoms such as protein in the urine, an enlarged tongue, breathing problems, weakness, swelling of the extremities, skin and bowel changes, and difficulty swallowing.
Other Serious Problems
The presence and activity of excess abnormal plasma cells interferes with the normal production of red blood cells and can lead to anemia, a deficiency in red blood cells that interferes with the delivery of oxygen to tissues throughout the body, causing fatigue, weakness and possibly heart problems. White blood cell production is also affected, leading to increased risk of reduced immunity and repeated infection. The Mayo Clinic advises that those with multiple myeloma may be more susceptible to conditions such as pneumonia, sinusitis, skin infections, bladder or kidney infections and shingles because of the body's impaired ability to produce antibodies. The MMHA also notes that reduced production of platelets can interfere with the blood's ability to clot, causing easy bruising and bleeding.
Rarely, multiple myeloma can cause a thickening of the blood (called hyperviscosity syndrome), interfering with blood flow to the skin, fingers, toes, nose, kidneys and brain, according to the MMHA.
