or '''leukaemia''' (see
Spelling Differences ) is a
Cancer of the
Blood or
Bone Marrow characterized by an abnormal proliferation of blood cells, usually white blood cells (
Leukocytes ). It is part of the broad group of diseases called
Hematological Neoplasms .
Damage to the bone marrow, by way of displacing the normal marrow cells with increasing numbers of malignant cells, results in a lack of blood
Platelet s, which are important in the
Blood Clotting process. This means people with leukemia may become
Bruised ,
Bleed excessively, or develop pinprick bleeds (
Petechiae ).
White blood cells, which are involved in fighting pathogens, may be suppressed or dysfunctional, putting the patient at the risk of developing
Infections .
Finally, the red blood cell deficiency leads to
Anaemia , which may cause
Dyspnea . All symptoms may also be attributable to other diseases; for
Diagnosis ,
Blood Test s and a
Bone Marrow Biopsy are required.
Some other related symptoms
- Fever , chills, and other flu-like symptoms
- Weakness and fatigue
- Loss of Appetite and/or weight
- Swollen or bleeding gums
- Neurological symptoms ( Headache )
Leukemia is a broad term covering a spectrum of diseases.
Leukemia is clinically and pathologically split in to its ''
Acute '' and ''
Chronic '' forms.
- ''Acute leukemia'' is characterized by the rapid growth of immature blood cells. This crowding makes the bone marrow unable to produce healthy blood cells. Acute forms of leukemia can occur in children and young adults. (In fact, it is a more common cause of death for children in the US than any other type of malignant disease). Immediate treatment is required in acute leukemias due to the rapid progression and accumulation of the malignant cells, which then spill over into the bloodstream and spread to other organs of the body. If left untreated, the patient will die within months or even weeks.
- ''Chronic leukemia'' is distinguished by the excessive buildup of relatively mature, but still abnormal, blood cells. Typically taking months to years to progress, the cells are produced at a much higher rate than normal cells, resulting in many abnormal white blood cells in the blood. Chronic leukemia mostly occurs in older people, but can theoretically occur in any age group. Whereas acute leukemia must be treated immediately, chronic forms are sometimes monitored for some time before treatment to ensure maximum effectiveness of therapy.
Furthermore, the diseases are classified according to the type of abnormal cell found most in the blood.
Combining these two classifications provides a total of four main categories:
- Acute Lymphocytic Leukemia (ALL) is the most common type of leukemia in young children. This disease also affects adults, especially those age 65 and older.
- Acute Myelogenous Leukemia (AML) occurs more commonly in adults than in children. This type of leukemia was previously called acute nonlymphocytic leukemia.
- Chronic Lymphocytic Leukemia (CLL) most often affects adults over the age of 55. It sometimes occurs in younger adults, but it almost never affects children.
- Chronic Myelogenous Leukemia (CML) occurs mainly in adults. A very small number of children also develop this disease.
The most common forms in adults are AML and CLL, whereas in children ALL is more prevalent.
The exact cause of leukemia is unknown but is influenced by both genetic and environmental factors. Leukemias, like other cancers, result from
Somatic Mutation s in the
DNA which activate
Oncogene s or inactivate
Tumour Suppressor Gene s, and disrupt the regulation of cell death, differentiation or division. These mutations may occur spontaneously or as a result of exposure to
Radiation or
Carcinogenic substances and are likely to be influenced by genetic factors. Cohort and case control studies have linked exposure to
Petrochemicals , such as
Benzene , and
Hair Dye s to the development of leukemia.
Viruses have also been linked to some forms of leukemia. Certain cases of ALL are associated with viral infections by either the
Human Immunodeficiency Virus (HIV, responsible for
AIDS ) or
Human T-lymphotropic Virus (HTLV-1 and -2, causing
Adult T-cell Leukemia/lymphoma ).
Fanconi Anemia is also a risk factor for developing
Acute Myelogenous Leukemia .
