Multiple myeloma (MM) is a malignant tumor of plasma cell characterized by overproduction of abnormal plasma cells in the bone marrow and skeletal destruction. The clinical features are bone pain, renal impairment, immunodeficiency, anemia and presence of abnormal immunoglobulins (Ig).

An inability of the tubules in the kidney to reabsorb small molecules, causing increased urinary loss of electrolytes (sodium, potassium, bicarbonate), minerals, glucose, amino acids, and water.