Welcome to my blog, today we are going to discuss on Leukemia and it’s causes

Leukaemia

Leukaemia is a malignant proliferation of white blood cell precursors by the bone marrow. It results in the uncontrolled increase in the production of leukocytes and/ or their precursors. As the tumour cells enter the blood the total leukocyte count is usually raised but in some cases it may be normal or even low. The proliferating immature leukemia blast cells crowd out other blood cells formed in bone marrow, causing anemia, thrombocytopenia and leukopenia (pancytopenia). Because the leukocytes are immature when released, immunity is reduced and the risk of infection high.

Causes of leukaemia

Some causes of leukaemia are known but many cases cannot be accounted for. Some people may have a genetic predisposition triggered by environmental factors, including viral infection. Other known causes include ionising radiation, chemicals and genetic factors. Ionizing radiationi Radiation from, for example, X-rays and radioactive isotopes causes malignant changes in the precursors of white blood cells. The DNA of the cells may be damaged and some cells die while others reproduce at an abnormally rapid rate. Leukemia may develop at any time after irradiation, even 20 or more years later.

Chemicals

Some chemicals, e.g. benzene, cytotoxic drugs and asbestos,generate mutations in the DNA of the white blood cell precursors in the bone marrow.

Genetic factors

Identical twins of leukaemia sufferers have a much higher risk than normal of developing the disease, suggesting involvement of genetic factors.

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Types of leukaemia

Leukaemias are usually classified according to the type of cell involved, the maturity of the cells and the rate at which the disease develops

Acute leukaemias

These types usually have a sudden onset and affect the poorly differentiated and immature blast’ cells. They can be aggressive diseases, especially in older people. The rapid progress of bone marrow invasion quickly causes bone marrow failure and culminates in anaemia, hemorrhage and susceptibility to infection. The mucous membranes of the mouth and upper gastrointestinal tract are most commonly affected. Leukocytosis is usually present in acute leukaemia. The bone marrow is packed with large numbers of immature and abnormal cells. Acute myeloblastic leukaemia

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Acute myeloblastic leukemia (AML)

it involves proliferation of myeloblasts and is most common in adults between the ages of 25 and 60, the risk gradually increasing with age. The disease can often be cured or long-term remission achieved.

Acute lymphoblastic leukemia

Acute lymphoblastic leukaemia (ALL) is seen mainly in children, who have a better prognosis than adults, with up to 70% achieving cure. The cell responsible is a primitive B-lymphocyte.


Chronic leukaemias

These conditions are less aggressive than the acute forms and the leukocvtes are more differentiated, i.e. at the ‘-cyte’ stage Leukocytosis is a feature of chronic leukaemia; there is crowding of the bone marrow with immature and abnormal leukocytes, although this varies depending on the form of the disease Chronic myeloid leukaemia

Chronic myeloid leukaemia (CML)

it occurs at all ages. Although its onset is gradual, in most patients it eventually reaches a rapidly progressive stage similar to AML and proves fatal; it may sometimes progress to ALL, however, which has a better prognosis. It is caused by an abnormality of chromosomes 22 and 9 (Philadelphia chromosome). Death usually occurs within 5 years.

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) involves proliferation of B-lymphocytes; it is usually less aggressive than ML. It is most often seen in the elderly; disease progression is usually
slow, and survival times can be as long as 25 years.