Leukaemia is cancer of body's Blood-forming tissues, including the Bone marrow and lymph system. The word leukaemia means, "white Blood" in Greek. The disease usually starts in the white Blood cells. Under normal circumstances, white Blood cells are potent infection fighters. These cells normally grow and divide in an orderly, controlled way, as body needs them. But leukaemia disrupts this process. In people with leukaemia, the Bone marrow produces a large number of abnormal white Blood cells. They look different from normal Blood cells and don't function properly. Eventually, they block production of normal white Blood cells, impairing the ability to fight off infection. Leukaemia cells also crowd out other types of Blood cells produced by the Bone marrow, including red Blood cells, which carry oxygen to tissues throughout the body, and platelets, which help form Blood clots that control bleeding.

Circulatory System

Leukaemia is classified in two ways. The first is by how fast the leukemia progresses:

Acute leukaemia: In acute leukaemia, the abnormal Blood cells are immature Blood cells (blasts). They can't carry out their normal work, and they multiply rapidly, so the disease worsens quickly. Acute leukaemia requires aggressive, immediate treatment. Chronic leukaemia: This type of leukaemia involves more mature Blood cells. These Blood cells replicate or accumulate more slowly and can function normally for a period of time. Some forms of chronic leukaemia produce no symptoms and can go unnoticed or undiagnosed for years.

The second type of classification is by type of white blood Cell affected:

Lymphocytic leukaemia: This type of leukaemia affects the lymphoid cells or lymphocytes, which form lymphoid or Lymphatic tissue. This tissue is the main component of the immune system and is found in places throughout body, including lymph nodes, Spleen and tonsils. Myelogenous leukaemia:This type of leukaemia affects the myeloid cells. The myeloid Cell line includes cells that later develop into red Blood cells, white Blood cells and platelet-producing cells.

The major types of leukemia are:

Acute myelogenous leukaemia (AML):This is the most common type of leukaemia. It occurs in children and adults. It's also called acute nonlymphocytic leukaemia. Acute lymphocytic leukaemia (ALL).This is the most common type of leukaemia in young children. ALL accounts for nearly 75 percent of all childhood leukaemias. Chronic myelogenous leukaemia (CML).This type of leukaemia mainly affects adults. It's associated with a chromosome abnormality called the Philadelphia chromosome. A person with CML may have few or no symptoms for months or years before entering a phase in which the leukemia cells grow more quickly. Chronic lymphocytic leukaemia (CLL).With CLL, another common adult leukaemia, one may feel well for years without treatment. CLL is more common in Jewish people of Russian or Eastern European descent. It almost never affects children.

These factors placed at an increased risk of developing some types of leukaemia:

Cancer therapy: People who've had certain types of chemotherapy and radiation therapy for other cancers have a slightly greater risk of developing certain types of leukemia many years later. Genetics: Genetic abnormalities seem to play a role in the development of leukemia. Certain genetic diseases, such as Down syndrome, are associated with increased risk of leukemia. Exposure to radiation and certain chemicals: People exposed to very high levels of radiation, such as survivors of an atomic bomb blast or a nuclear reactor accident, have an increased risk of developing leukemia. Exposure to certain chemicals, such as benzene — which is found in unleaded gasoline, tobacco smoke and the chemical industry — is also linked to greater risk of some kinds of leukemia.

Leukaemia cells are abnormal cells that cannot do what normal Blood cells do. They cannot help the body fight infections. For this reason, people with leukaemia often get infections. In acute leukaemia, symptoms appear and get worse quickly. In chronic leukaemia, symptoms may not appear for a long time; when symptoms do appear, they generally are mild at first and get worse gradually and have fevers. In acute leukaemia, the abnormal cells may collect in the Brain or Spinal Cord (also called the central Nervous system or CNS). The result may be headaches, vomiting, confusion, loss of muscle control, and seizures. Leukaemia cells also can collect in the testicles and cause swelling. Also, some patients develop sores in the eyes or on the Skin. Leukaemia also can affect the Digestive tract, kidneys, Lungs, or other parts of the body. In chronic leukaemia, the abnormal Blood cells may gradually collect in various parts of the body. Chronic leukaemia may affect the Skin, central Nervous system, Digestive tract, kidneys, and testicles. These are some of the common symptoms of leukaemia:

Fever, chills, and other flu-like symptoms; Weakness and fatigue; Frequent infections; Loss of appetite and/or weight; Swollen or tender lymph node, Liver, or Spleen; Easy bleeding or bruising; Tiny red spots (called petechiae) under the Skin; Swollen or Bleeding Gums; Sweating, especially at night; and/or Bone or joint pain.

Leukaemia patients should undergo the following diagnostic exams:

Physical exam: physical signs of leukaemia should be looked for, such as swelling of lymph nodes, Liver and Spleen. Blood tests: By looking at a sample of Blood, it should be determined that if one has abnormal levels of white Blood cells or platelets — which are both suggestive indicators of leukemia. Bone marrow sample: If it is suspectd leukaemia, he or she may refer to an oncologist or who specializes in Blood (hematologist).

Treatment for leukaemia is complex. It depends on many factors, including age and overall health, the type of leukaemia one have and whether it has spread to other parts of body. Therapies used to fight leukaemia include:

Chemotherapy: Chemotherapy is the major form of treatment for leukaemia. This treatment uses chemical agents to kill leukaemia cells. Depending on the type of leukaemia one has, one may receive a single drug or a combination of one or more drugs. These drugs may come in a pill form, or they may be injected directly into a vein. Biological therapy: Also known as immunotherapy, biological therapy uses substances that bolster immune system's response to cancer. Radiation therapy: Radiation therapy uses X-rays or other high-energy rays to damage leukaemia cells and stop their growth. One may receive radiation in one specific area of their body where there is a collection of leukaemia cells. Bone marrow transplant: This process replaces leukaemic Bone marrow with leukaemia-free marrow. In this treatment, one receives high doses of chemotherapy or radiation therapy, which destroys leukaemia-producing Blood marrow. This marrow is then replaced by Bone marrow from a compatible donor. Stem Cell transplant: Stem Cell transplant is similar to Bone marrow transplant except the cells are collected from stem cells that circulate in the bloodstream (peripheral Blood), after using a medicine that causes cells to be released from the Bone marrow. Clinical trials: Some people with leukaemia choose to enroll in clinical trials to try out experimental treatments or new combinations of known therapies. Supportive care: No matter what kind of cancer therapy one chooses, but one likely need’s medications to control pain and side effects.

Patients who have a Bone marrow transplant face an increased risk of infection, bleeding, and other side effects of the large doses of chemotherapy and radiation they receive.