Leukopenia
This is a decrease in leukocyte count in peripheral blood (normal range is 4-8×109 leukocytes/l). It can be caused by various reasons: decreased production of leukocytes in the bone marrow, rapid destruction of leukocytes in the blood, or impaired distribution of neutrophils. The production of leukocytes is most commonly disrupted by various drugs (e.g., antineoplastics) and chemical substances (e.g., benzene compounds), ionizing radiation, sometimes infectious diseases (e.g., viral hepatitis, infectious mononucleosis). The decrease can be accelerated by drugs (e.g., phenacetin, indomethacin, antimalarials, antiepileptics), less frequently it accelerates in cases of systemic lupus erythematosus, severe infectious diseases, or enlarged spleen. When agitated, experiencing very high physical exertion, or under the influence of drugs (such as adrenaline, nonsteroidal anti-inflammatory drugs), the leukocyte count in the body remains normal, and a decrease may only be observed in the blood samples being tested. A decreased leukocyte count may indicate blood disorders (e.g., aplastic or megaloblastic anemia, certain malignant tumors and their metastases to the bone marrow). The most commonly diagnosed form of leukopenia is neutropenia – a decrease in neutrophil count, less frequently – lymphocytopenia – a decrease in lymphocyte count.
Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė