What is leukemia, and how does it occur?
We defined leukemia as cancer of blood-forming tissues, which leads to an excessive increase in the production of blood cells, and in most cases, this increase affects white blood cells. The problem in leukemia is that these white blood cells are abnormal (called leukemia cells), and they can’t do what normal white blood cells do. Also, this increase in the production of white blood cells affects the production of red blood cells and platelets.
The net result is:
- Increased production of abnormal white blood cells (leukemia cells) that can’t protect the body, which reduces the immunity
- Reduced production of red blood cells and reduced oxygen supply to body tissues
- Reduced production of platelets, which increases the bleeding tendency
Causes of leukemia
We don’t know specific causes for leukemia, but there are some risk factors, such as:
- Smoking
- Positive family history of leukemia
- Genetic diseases, such as Down syndrome
- Cancer treatment, either radiotherapy or chemotherapy
- Exposure to ionizing radiation and benzene
- Blood diseases, such as Myelodysplastic Syndrome, which known as preleukemia
- Immune suppression as occurs with organ transplantation or immune-suppressive drugs
The clinical picture of leukemia
Manifestations of leukemia include:
› Bleeding tendency: Reduced platelet production makes the healing of wounds slow an difficult. Thus, leukemia patients bleed and bruise easily and have petechiae (red spots under the skin).
› Anemia: Reduced production of red blood cells impairs oxygen supply to body organs and tissues, and this causes symptoms like pale skin, weakness, fatigability, and difficulty breathing.
› Susceptibility to infections: Leukemia cells are unable to fight infections. Thus, leukemia patients are immunocompromised and susceptible to invasion by any organism.
› Other symptoms, such as fever, weight loss, night sweating, bone pain, painless enlarged lymph nodes, and enlarged liver and spleen
›» This cancer may spread to any part of the body, such as the brain, heart, lung, kidneys, and testes, and causes symptoms according to the involved organ.
Types of leukemia
Leukemia may be acute (sudden onset and rapid progression) or chronic (gradual onset and slow progression). Also, it may be myeloid or lymphocytic, according to the type of involved immature cells. Thus, we have four types of leukemia:
A) Acute lymphocytic leukemia (ALL): It is the most common type in children; it can also affect adults older than 50 years.
B) Chronic lymphocytic leukemia (CLL): It is the most common type in people older than 50 years, but it may affect young adults. It is rare in children. It is more common in males.
C) Acute myelogenous leukemia (AML): It affects children and adults, and it is the most common type in adults.
D) Chronic myelogenous leukemia (CML): It affects adults and rare in children. It represents 15% of leukemia cases in the United States.
Diagnosis of leukemia
After the physical examination, if your doctor suspects leukemia -due to causes, such as pale skin, enlarged liver and spleen, and swollen lymph nodes-, he will ask you to do some tests to confirm this diagnosis. These tests include:
• Complete blood picture (CBC): It determines the number and maturity of blood cells. In leukemia, there is a high number of abnormal white blood cells and low red blood cell count and platelet count.
• Bone marrow biopsy: It helps the doctor to identify the type of leukemia.
