Brief Summary of Multiple myeloma

Multiple myeloma is also known as malignant plasmacytoma, plasma cell myeloma, and myelomatosis. It’s a disseminated neoplasm of marrow plasma cells that infiltrates bone to produce osteolytic lesions throughout the skeleton (flat bones, vertebrae, skull, pelvis, ribs); in late stages, it infiltrates the body organs (liver, spleen, lymph nodes, lungs, adrenal glands, kidneys, skin, GI tract). Multiple myeloma strikes mostly men older than age 40.
The prognosis is usually poor because the disease is commonly diagnosed after it has already infiltrated the vertebrae, pelvis, skull, ribs, clavicles, and sternum. By then, skeletal destruction is widespread and, without treatment, leads to vertebral collapse. Early diagnosis and treatment prolong the lives of many patients by 3 to 5 years. Death usually follows complications, such as infection, renal failure, hematologic disorders, fractures, hypercalcemia, hyperuricemia, or dehydration.

Pathophysiology
Multiple myeloma is characterized by excessive growth and malformation of plasma cells in bone marrow. The growth of these extra cells interferes with the production of red blood cells, white blood cells, and platelets, resulting in anemia, susceptibility to infection, and increased tendency toward bleeding. As the cancer cells grow and expand, pain and destruction of bone occurs.

Signs and symptoms
The earliest symptom of multiple myeloma is usually back pain. This disease should be considered in diagnosis or treatment of elderly patients with new onset of lower back pain. Arthritic symptoms may also occur: achiness, joint swelling, and tenderness, possibly from vertebral compression. Other effects include fever, malaise, slight evidence of peripheral neuropathy (such as peripheral paresthesia), pathologic fractures, and easy bruising.

As multiple myeloma progresses, symptoms of vertebral compression may become acute, accompanied by anemia, weight loss, thoracic deformities (ballooning), and loss of body height due to vertebral collapse.

Renal complications such as pyelonephritis (caused by tubular damage from large amounts of Bence Jones protein, hypercalcemia, and hyperuricemia) may occur.

Severe, recurrent infection, such as pneumonia, may follow damage to nerves associated with respiratory function.

Diagnosis
After a physical examination and a careful medical history, the following diagnostic tests and nonspecific laboratory abnormalities confirm the presence of multiple myeloma:

• Complete blood count shows moderate or severe anemia. The differential may show 40% to 50% lymphocytes but seldom more than 3% plasma cells. An elevated erythrocyte sedimentation rate results from increased clumping of red blood cells (rouleaux formation) caused by increased concentration of serum immunoprotein.
• Urine studies may show Bence Jones protein and hypercalciuria. Absence of Bence Jones protein doesn’t rule out multiple myeloma; however, its presence almost invariably confirms the disease.
• Bone marrow aspiration detects myelomatous cells (an abnormal number of immature plasma cells).
• Serum electrophoresis shows an elevated globulin spike that’s electrophoretically and immunologically abnormal.
• X-rays during early stages may show only diffuse osteoporosis. Eventually, they show multiple, sharply circumscribed osteolytic (punched-out) lesions, particularly on the skull, pelvis, and spine—the characteristic lesions of multiple myeloma.
• Excretory urography can assess renal involvement. To avoid precipitation of Bence Jones protein, iothalamate or diatrizoate is used instead of the usual contrast medium. Also, although oral fluid restriction is usually standard before excretory urography, patients with multiple myeloma receive large quantities of fluid, generally orally but sometimes I.V., before this test is done.

Treatment
Long-term treatment of multiple myeloma consists mainly of chemotherapy to suppress plasma cell growth and control pain. Also, adjuvant local radiation reduces acute lesions, such as collapsed vertebrae, and relieves localized pain.
Other treatment usually includes a melphalan-prednisone combination in high intermittent doses or low continuous daily doses, and an analgesic for pain. For spinal cord compression, the patient may require a laminectomy; for renal complications, dialysis. Bone marrow transplantation is sometimes used in younger patients, but the procedure’s long-term results are unknown.
Because the patient may have bone demineralization and may lose large amounts of calcium into blood and urine, he’s a prime candidate for renal calculi, nephrocalcinosis and, eventually, renal failure due to hypercalcemia. Hypercalcemia is managed with hydration, a diuretic, a corticosteroid, oral phosphate, and I.V. mithramycin to decrease serum calcium levels.