Multiple myeloma

What is multiple myeloma?

Multiple myeloma is a malignant (cancerous) condition characterized by the uncontrolled proliferation (rapid reproduction) and dysfunction of the plasma cells in the bone marrow.

Plasma cells are white blood cells that respond to an invading organism (viral or bacterial) by producing antibodies to react to it. In multiple myeloma, the abundance of plasma cells overproduce only one kind of antibody (or immunoglobulins called IgA or IgG), while underproducing other types of antibodies. This makes the individual particularly susceptible to infection. When healthy bone marrow is replaced by malignant plasma cells, as occurs in this illness, there is a reduced production of red blood cells, platelets, and granulocytes, which may result in anemia, recurrent infection, or a bleeding tendency. As the plasma cell tumors expand within the bone, they cause destruction of bone tissue resulting in fractures and spinal cord compression. The level of calcium in the blood can be markedly increased as bone is destroyed and can cause damage to the kidneys, resulting in renal failure.

Amyloidosis (a disease in which a substance containing protein and starch accumulates in tissues and organs) occurs in approximately fifteen percent of individuals with multiple myeloma. Little is known about the cause of multiple myeloma. Theories suggest a viral cause, a genetic cause, or that it may be related to the exposure to herbicides or radiation. Individuals with autoimmune diseases (in which the immune system reacts against the body's own tissues) are more often affected with multiple myeloma. Multiple myeloma usually occurs in middle to older aged individuals and is extremely rare before age 40. Approximately 12,500 new cases are reported annually in the US.

How is it diagnosed?

History: Individuals may report pain in the bones, especially the vertebrae, pelvis, ribs, and skull. If the vertebrae are affected, they may collapse and compress nerves, causing numbness or paralysis. There may be a history of recurrent bacterial infections. Anemia symptoms can include increased fatigue and shortness of breath upon exertion. Nausea, confusion, frequent urination (polyuria) and constipation may be present due to increased calcium level in the blood (hypercalcemia), or pending renal failure. Symptoms of amyloidosis may include weakness, weight loss, ankle edema, lightheadedness or fainting (syncope), or pins and needles feelings in the fingers and toes.

Physical exam: Complete physical exam may reveal pallor, tenderness with pressure over an involved bone, and, rarely, soft tissue masses. Cardiac examination may reveal an abnormal heart rhythm due to anemia, excessive amount of potassium in the blood (hyperkalemia), or amyloid heart diseaseNeurologic exam may show evidence of nerve disorder (neuropathy) or spinal cord compression. Carpal tunnel syndrome may be present in the upper extremities.

Tests: A complete blood count (CBC) indicates anemia (decreased red blood cells), and other cell count discrepancies. Blood chemistry and/or urinalysis can identify excess in immunoglobulin and detect abnormally high levels of calcium (hypercalcemia) from bone breakdown. A bone marrow biopsy will frequently show an overgrowth of malignant plasma cells. X-rays and CT scan can detect areas of destroyed bone, or an enlarged heart in cases of cardiac amyloidosis.

How is multiple myeloma treated?

Therapy for multiple myeloma includes simultaneous treatment of the disease and of complications related to the disease. Treatment of the disease consists of anti-cancer drugs (chemotherapy) to reduce the number of abnormal plasma cells. Radiation therapy is frequently given to areas of diseased bone to relieve pain and help prevent fractures. Treatment of associated complications may include blood transfusions to correct anemia and antibiotics to combat infections. Hypercalcemia and renal failure are treated with a combination of increased fluid intake, glucocorticoids (hormones produced by the adrenal glands), and chemotherapy. Pain relievers (analgesics) are often needed. Bone marrow transplantation is occasionally performed in highly selective situations at large cancer centers.

Medications

• Anticancer and cortisone drugs (chemotherapy).
• Pain relievers.
• Antibiotics to fight infections.

What might complicate it?

Complications include increased risk of infection, destruction of bone tissue that may result in fractures, spinal cord compression with possible neurological impairment, damaged kidneys or renal failure due to increased levels of calcium and immunoglobulin in the blood, and anemia or bleeding disorders.

Predicted outcome

The severity of the illness and prognosis varies, but, in general, the five-year survival rate is less than twenty percent.

Alternatives

Similar symptoms arise from benign situations involving chronic inflammation, sometimes referred to as monoclonal gammopathy of undetermined significance (MGUS). Other diseases with a similar appearance include chronic lymphocytic leukemia, non-Hodgkin's lymphoma and amyloidosis.

Appropriate specialists

Hematologist or oncologist. Depending upon complications; surgeon, orthopedist, cardiologist, nephrologist, and radiation oncologist.

Last updated 27 May 2012