Mean LOS 74 days Description Medical Lymphoma and

Nonacute Leukemia with CC

Leukemia is a malignant disease of the blood-forming organs that leads to a transformation of stem cells or early committed precursor cells and thus to an abnormal overproduction of certain leukocytes. Two types of chronic leukemia commonly occur: chronic lymphocytic leukemia (CLL) and chronic myelogenous leukemia (CML).

568 Leukemia, Chronic

CLL, the most common form of leukemia in adults in the United States, involves lymphocytes (B cells)—cells that derive from stem cells and that circulate among blood, lymph nodes, and lymphatic organs. In CLL, an uncontrollable spread of abnormal, small lymphocytes occurs in the bone marrow, lymphoid tissues, and blood. In CLL, an underproduction of immunoglob-ulins (antibodies) leads to increased susceptibility to infections. Some patients also develop antibodies to red blood cells and platelets, which then leads to anemia and thrombocytopenia.

CML is characterized by the abnormal overgrowth of myeloblasts, promyelocytes, metamye-locytes, and myelocytes (all granulocytic precursors) in body tissues, peripheral blood, and bone marrow. In CML, the bone marrow becomes 100% cellular (rather than 50% cellular and 50% fat, the normal composition). The spleen enlarges with a greatly expanded red pulp area. CML has two phases: insidious chronic phase and acute phase. In the insidious chronic phase, chronic leukemia originates in the pluripotent stem cell, with an initial finding of hypercellular marrow with a majority of normal cells. After a relatively slow course for a median of 4 years, the patient with chronic leukemia invariably enters a blast crisis, or acute phase.

Both CLL and CML may metastasize to the blood, lymph nodes, spleen, liver, central nervous system, and other organs. The American Cancer Society predicts approximately 30,000 new cases of all types of leukemia will occur in the United States annually; an estimated 17,000 of those cases are CLL.

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