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Leukemia is a disease of cancerous cell of the bone or bone marrow, but can be spread to different places such as the spleen, liver, central nervous system and many other organs. This usually happens when white blood cells starts to divide uncontrollably. Since it covers a whole spectrum of diseases, it is a family of hematological neoplasm.

Leukemia is either chronic or acute. Chronic leukemia worsens slower than acute leukemia. People with chronic leukemia experience symptoms slower. The abnormal blood cells can still function properly but over time the disease gets worse. People diagnosed with acute leukemia experience symptoms faster. The abnormal blood cells increase rapidly and cannot function properly.

Leukemia is determined by the type of white blood cell that is being affected. There are 2 types. One type is called lymphoid cell and the other is called myeloid cell.

There are many different types and subtypes of leukemia, but these 4 types are the most common and kill the most people.

Chronic Lymphocytic Leukemia, also called Chronic Lymphoblastic Leukemia (CLL), occurs mostly in

adults over the age of 55. It rarely occurs in children. Chronic lymphocytic leukemia occurs when the bone marrow makes too many abnormal lymphocyte cells (also known as leukemia cells). These cells are not able to fight infections very well and thus the person diagnosed can get sick easier. As the number of lymphocyte increase, the number of healthy red and white blood cells decrease. This may result in easy bleeding, infections and anemia.

Chronic lymphocytic leukemia spreads slowly, so it develops in five stages starting at stage 0. As the stages progress, the amount of red blood cells decrease and the spleen, liver and lymph nodes grow larger in size.

Chronic Myeloid Leukemia (CML)

Chronic Myeloid Leukemia, also called Chronic Myelogenous Leukemia (CML), occurs mostly in adults and rarely in children. Chronic myeloid leukemia occurs when a large amount of mature stem cells develop into a type of white blood cell called granuloctyes, also known as leukemic cells. These leukemic cells can build up in the bone marrow, leaving very little room for healthy blood cells to function. Infection, anemia and easy bleeding can occur when this happens.

Chronic myeloid leukemia has 3 phases. The first phase is called the chronic phase and less than 10% of the cells in the blood and bone marrow have developed into blast cells (immature blood cells). The second phase is called accelerated phase and 10%-19% of the cells have developed into blast cells. The third phase is called blastic phase and that is when 20% or more of the cells in the blood and bone marrow have developed into blast cells. If tiredness, fever and a large spleen occurs during this phase, it is called a blast crisis.

Acute Lymphocytic Leukemia (ALL)

Acute Lymphocytic Leukemia, also known as Acute Lymphoblastic Leukemia (ALL), is the most common type of leukemia found in children under the age of 15. However the risk of getting ALL increases if the person is over the age of 45. Acute lymphocytic leukemia occurs when the bone marrow produces abnormal uniformed cells called blasts. These blasts do not develop properly and therefore fails to function. These abnormal cells produce quickly, so they leave little room for healthy blood cells to function. Patients may see symptoms faster.

Acute Myeloid Leukemia (AML)

Acute Myeloid Leukemia, also known as Acute Myelogenous Leukemia (AML), occurs in both adults and children, however children are at a higher risk in getting this type of cancer than adults. What happens during AML is that there are too many immature blood-forming cells that form in the bone marrow. These cells skip the process of developing into granulocytes or monocytes so they just crowd around, outnumbering the healthy blood cells. Granulocytes and monocytes are important cells needed to help fight infections. Without these cells, the patient might experiences fever, fatigue or loss of weight and appetite faster.

picture from Veterinary Clinical Pathology Clerkship Program

www.vet.uga.edu/vpp/clerk/waikart/index.php

accessed Apr 28, 09