In leukaemia one particular type of blood cell becomes malignant (evil), like a cancer, and takes over the bone marrow. The malignant (evil) cell is produced at such a fast rate that it fills up all the available space in the bone marrow and is squeezed out into the bloodstream.
Sometimes the malignant (evil) cells are called blast cells. They don't leave room for the other normal blood cells to develop, so the healthy blood cells are reduced in number in the marrow and the blood. It's usually the white blood cells, the ones that are involved in fighting infection, that become malignant (evil). Very rarely, the red cells or the platelets are at fault. The exact name of the leukaemia depends on the type of cell that is involved.
In a person with leukaemia, the bone marrow makes abnormal white blood cells. The abnormal cells are leukaemia cells. Unlike normal blood cells, leukaemia cells don't die when they should. They may crowd out normal white blood cells, red blood cells, and platelets. This makes it hard for normal blood cells to do their work.
Why is it called Leukaemia?
The term “Leukaemia” that is used now comes from the Greek words “leukos” and “heima,” also meaning “white blood”.
What are the different types of Leukaemia?
Leukaemia is basically divided into lymphocytic and myelocytic leukaemia. These two types are then divided into acute or chronic, depending on how well developed and mature the evil cells look under the microscope.
Different to what you might expect, acute leukaemia is much more serious than chronic leukaemia. In fact, there is a common type of leukaemia called chronic lymphocytic leukaemia (or CLL) that is most common in older people and that may have no effect on your health at all. CLL is usually picked up on a routine blood count and may require no treatment.
The types of leukaemia can be grouped based on how quickly the disease develops and gets worse. Leukaemia is either chronic (which usually gets worse slowly) or acute (which usually gets worse quickly):
•Chronic leukaemia: Early in the disease, the leukaemia cells can still do some of the work of normal white blood cells. People may not have any symptoms at first. Doctors often find chronic leukaemia during a routine check up - before there are any symptoms. Slowly, chronic leukaemia gets worse. As the number of leukaemia cells in the blood increases, people get symptoms, such as swollen lymph nodes or infections. When symptoms do appear, they are usually mild at first and get worse gradually.
•Acute leukaemia: The leukaemia cells can't do any of the work of normal white blood cells. The number of leukaemia cells increases rapidly. Acute leukaemia usually worsens quickly.
The types of leukaemia also can be grouped based on the type of white blood cell that is affected. Leukaemia can start in lymphoid cells or myeloid cells. Leukaemia that affects lymphoid cells is called lymphoid, lymphocytic, or lymphoblastic leukaemia. Leukaemia that affects myeloid cells is called myeloid, myelogenous, or myeloblastic leukaemia.
There are four common types of leukaemia:
•Chronic lymphocytic leukaemia (CLL): CLL affects lymphoid cells and usually grows slowly. It accounts for more than 15,000 new cases of leukaemia each year. Most often, people diagnosed with the disease are over age 55. It almost never affects children.
•Chronic myeloid leukaemia (CML): CML affects myeloid cells and usually grows slowly at first. It accounts for nearly 5,000 new cases of leukaemia each year. It mainly affects adults.
•Acute lymphocytic (lymphoblastic) leukaemia (ALL): ALL affects lymphoid cells and grows quickly. It accounts for more than 5,000 new cases of leukaemia each year. ALL is the most common type of leukaemia in young children. It also affects adults.
•Acute myeloid leukaemia (AML): AML affects myeloid cells and grows quickly. It accounts for more than 13,000 new cases of leukaemia each year. It occurs in both adults and children.
•Hairy cell leukaemia is a rare type of chronic leukaemia.
