Multiple myeloma is a cancer of your plasma cells, a type of white blood cell present in your bone marrow. Plasma cells normally make proteins called antibodies to help you fight infections.
In multiple myeloma, a group of abnormal plasma cells (myeloma cells) multiplies, raising the number of plasma cells to a higher than normal level. Since these cells normally make proteins, the level of abnormal proteins in your blood also may go up. Health problems caused by multiple myeloma can affect your bones, immune system, kidneys and red blood cell count.
If you have multiple myeloma but don't have symptoms, your doctors may just monitor your condition. If you're experiencing symptoms, a number of treatments are available to help control multiple myeloma.
Signs and symptoms of multiple myeloma can vary from person to person. Although the condition may not cause symptoms early in the disease, it's likely that you'll experience one or more of the following as the disease progresses:
- Bone pain, particularly in your back, pelvis, ribs and skull.
- Presence of abnormal proteins — which can be produced by myeloma cells — in your blood or urine. These proteins — which are antibodies or parts of antibodies — are called monoclonal, or M, proteins. Often discovered during a routine exam, monoclonal proteins may indicate multiple myeloma, but also can indicate other conditions.
- High level of calcium in your blood. This can occur when calcium from affected bones dissolves into your blood.
If you have a high calcium level in your blood, you may experience signs and symptoms such as:
- Excessive thirst and urination
- Loss of appetite
- Mental confusion
Other signs and symptoms of multiple myeloma may include:
- Anemia-related fatigue as myeloma cells replace oxygen-carrying red blood cells in your bone marrow
- Unexplained bone fractures
- Repeated infections — such as pneumonia, sinusitis, bladder or kidney infections, skin infections, and shingles
- Weight loss
- Weakness or numbness in your legs
When to see a doctor
If you're persistently more tired than you used to be, you've lost weight, and you experience bone pain, repeated infections, loss of appetite, excessive thirst and urination, persistent nausea, increased constipation, or weakness or numbness in your legs, your signs and symptoms may indicate multiple myeloma or other serious disease. See your doctor to determine the underlying cause.
Although the exact cause isn't known, doctors do know that multiple myeloma begins with one abnormal plasma cell in your bone marrow — the soft, blood-producing tissue that fills in the center of most of your bones. This abnormal cell then starts to multiply.
Because abnormal cells don't mature and then die as normal cells do, they accumulate, eventually overwhelming the production of healthy cells. In healthy bone marrow, less than 5 percent of the cells are plasma cells. But in people with multiple myeloma, more than 10 percent of the cells may be plasma cells.
Because myeloma cells may circulate in low numbers in your blood, they can populate bone marrow in other parts of your body, even far from where they began. That's why the disease is called multiple myeloma. Uncontrolled plasma cell growth can damage bones and surrounding tissue. It can also interfere with your immune system's ability to fight infections by inhibiting your body's production of normal antibodies.
Researchers investigating cause
Researchers are studying the DNA of plasma cells to try to understand what changes occur that cause these cells to become cancer cells. Though they haven't yet discovered the cause of these changes, they have found that almost all people with multiple myeloma have genetic abnormalities in their plasma cells that probably contributed to the cancer. For example, many myeloma cells are missing all or part of one chromosome — chromosome 13. Cells with a missing or defective chromosome 13 tend to be more aggressive and harder to treat than are cells with a normal chromosome 13.
A connection with MGUS
Multiple myeloma almost always starts out as a relatively benign condition called monoclonal gammopathy of undetermined significance (MGUS). In the United States, about 3 percent of people over the age of 50 have MGUS. Each year, about 1 percent of people with MGUS develop multiple myeloma or a related cancer. This condition, like multiple myeloma, is marked by the presence of M proteins — produced by abnormal plasma cells — in your blood. However, in MGUS, no damage to the body occurs.
Multiple myeloma isn't contagious. Most people who develop multiple myeloma have no clearly identifiable risk factors for the disease.
Some factors that may increase your risk of multiple myeloma include:
- Age. The majority of people who develop multiple myeloma are older than 50, with most diagnosed in their mid-60s. Few cases occur in people younger than 40.
- Sex. Men are more likely to develop the disease than are women.
- Race. Blacks are about twice as likely to develop multiple myeloma as are whites.
- History of a monoclonal gammopathy of undetermined significance. Every year 1 percent of the people with MGUS in the United States develop multiple myeloma.
- Obesity. Your risk of multiple myeloma is increased if you're overweight or obese.
Other factors that may increase your risk of developing multiple myeloma include exposure to radiation and working in petroleum-related industries.
Multiple myeloma can result in several complications:
- Impaired immunity. Myeloma cells inhibit the production of antibodies needed for normal immunity. Having multiple myeloma may make you more likely to develop infections, such as pneumonia, sinusitis, bladder or kidney infections, skin infections, and shingles.
- Bone problems. Multiple myeloma also can affect your bones, leading to erosion of bone mass and fractures. The condition may cause compression of your spinal cord. Signs of this medical emergency include weakness, or even paralysis, in your legs.
- Impaired kidney function. Multiple myeloma may cause problems with kidney function, including kidney failure. Higher calcium levels in the blood related to eroding bones can interfere with your kidneys' ability to filter your blood's waste. The proteins produced by the myeloma cells can cause similar problems, especially if you become dehydrated.
- Anemia. As cancerous cells crowd out normal blood cells, multiple myeloma can also cause anemia and other blood problems.
In many cases, multiple myeloma is discovered as part of routine blood and urine tests during a medical checkup. To increase the odds of catching this and other serious conditions as early as possible, follow the recommended schedule for your age and sex for general physical examinations. If you have symptoms that are common to multiple myeloma — such as back pain, weakness and fatigue, poor appetite and weight loss, or repeated infections — call your doctor. After your doctor sees you, you may be referred to a specialist in the diagnosis and treatment of cancer (oncologist). Because appointments can be brief and because there's often a lot of ground to cover, it's a good idea to be well prepared for your appointment. Here's some information to help you get ready and on what to expect from your doctor.
What you can do
- Note any symptoms you're experiencing. If you've had signs and symptoms of illness or are just not feeling like yourself, write down those details before your appointment. Your doctor will also want to know when you first noticed these symptoms and whether they've changed over time.
- List any other medical conditions with which you've been diagnosed. Your doctor will be especially interested to know if you've been diagnosed with any other plasma disorders, such as monoclonal gammopathy of undetermined significance (MGUS).
- Make a list of your medications. Include any prescription or over-the-counter medications you're taking, as well as all vitamins, supplements and herbal remedies.
- Take a family member or friend along, if possible. Sometimes it can be difficult to absorb all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
- Write down questions to ask your doctor.
Questions to ask your doctor at your initial appointment include:
- What may be causing my symptoms or condition?
- Are there any other possible causes?
- What kinds of tests do I need?
- What do you recommend for next steps in determining my diagnosis and treatment?
- Are there any restrictions that I need to follow in the meantime?
Questions to consider if your doctor refers you to an oncologist include:
- Do I have multiple myeloma?
- What stage of myeloma do I have?
- Does my myeloma have any high-risk features?
- What are the goals of treatment in my case?
- What treatment do you recommend?
- What are the possible side effects of treatment?
- If the first treatment isn't successful, what will we try next?
- Am I a candidate for stem cell transplantation?
- Do I need a medicine to strengthen my bones?
- What is the outlook for my condition?
In addition to the questions, don't hesitate to ask questions during your appointment at any time that you don't understand something. What to expect from your doctor
Your doctor is likely to ask you a number of questions. Thinking about your answers ahead of time can help you make the most of your appointment. A doctor who sees you for possible multiple myeloma may ask:
- What are your symptoms, if any?
- When did you first begin experiencing symptoms?
- How have your symptoms changed over time?
- Do your symptoms include bone pain? Where?
- Do your symptoms include nausea, lost appetite or weight loss?
- Do your symptoms include weakness or fatigue?
- Have you had repeated infections, such as pneumonia, sinusitis, bladder or kidney infections, skin infections, or shingles?
- Have you noticed any changes in your bowel habits?
- Have you been more thirsty or urinated more than usual?
- What else concerns you?
- Do you have any family history of plasma disorders such as MGUS?
- Have you been diagnosed or treated for any other medical conditions?
- Do you have a history of blood clots?
- What medications are you taking?
What you can do in the meantime
While you wait for your appointment, check with your family members to find out if any relatives have been diagnosed with multiple myeloma or with plasma disorders such as MGUS.