An increased WBC count is an indicator of high levels of leukocytes in the blood, usually caused by an increased production of these cells in response to an infection or a medical condition. The upper normal limit for leukocytes in the blood is considered to be 11.000 leukocytes per micro-liter of blood. A count that is more than this is considered to be a high white blood cell count. This figure will vary in the case of children, depending on their age and body weight.
There are many different causes of a high white blood cell count. They include:
- Infection: White blood cells are produced in the bone marrow to fight off bacteria and viruses that threaten to infect the body. Any infection will therefore result in an increased white blood cell count.
- Drug Reactions: Reactions to certain types of medications may result in an increased white blood cell count. These include drugs such as corticosteroids, beta-antagonists and lithium based drugs.
- Diseases of the Bone Marrow: Diseases such as lymphoma and leukemia, a form of blood cancer may also cause the bone marrow to produce excessive amounts of white blood cells.
- Disorders of the Immune System: Several such disorders including Graves’ disease and Crohn’s disease can result in an increased production of white blood cells. In the case of Graves’ disease, the immune system targets the thyroid gland causing hormonal changes that affect the levels of white blood cells.
- Acute lymphocytic leukemia
- Chronic lymphocytic leukemia
- Acute myelogenous leukemia
- Chronic myelogenous leukemia
- Severe allergic reactions
- Myelofibrosis
- Side effect of drugs such as corticosteroids and lithium
- Splenectomy (removal of the spleen)
- Bacterial infections
- Viral infections
- Polycythemia vera
- Rheumatoid arthritis
- Smoking
- Stress
- Seizures
answered by G R