- Leukemoid reaction
- A benign condition in which the high number of white blood cells found in a blood test resembles the numbers seen in leukemia. For example, infectious mononucleosis can return blood-test results with a leukemoid reaction.
* * *A moderate, advanced, or sometimes extreme degree of leukocytosis in the circulating blood, similar to that occurring in various forms of leukemia, but not the result of leukemic disease; usually, there is a disproportionate increase in the number of forms (including immature stages) in one series of leukocytes, and various examples of myelocytic, lymphocytic, monocytic, or plasmocytic l. may be also indistinguishable from leukocytosis that is associated with certain forms of leukemia. Leukemoid reactions are sometimes observed as a feature of: 1) infectious disease caused by certain bacteria and other biologic agents, e.g., tuberculosis, diphtheria, and chickenpox; 2) intoxication of various types, e.g., eclampsia, serious burns, and mustard gas poisoning; 3) malignant neoplasms, e.g., carcinoma of the colon, of the lung, of the kidney, or of other organs; 4) acute hemorrhage or hemolysis.- lymphocytic l. leukocytosis of varying degree, with adult lymphocytes and immature forms amounting to 40% (or more) of the total number of white blood cells in the circulating blood; may be observed in association with pertussis, infectious mononucleosis, gonorrhea, chickenpox, and sarcoidosis.- monocytic l. leukocytosis of varying degree, e.g., 30,000–40,000/mm3, with adult monocytes and immature forms amounting to 30% (or more) of the total number of white blood cells in the circulating blood; may be observed in association with tuberculosis, especially the first infection, miliary type.- myelocytic l. leukocytosis of at least moderate degree, e.g., 50,000 or more per mm3, with a few immature forms, e.g., 1 or 2% myelocytes, but chiefly mature polymorphonuclear leukocytes in the circulating blood; may be observed in association with tuberculosis, chronic osteomyelitis, various types of empyema, malaria, pneumococcal pneumonia, meningococcal meningitis, Hodgkin disease, and metastases of carcinoma in the bone marrow.
Medical dictionary. 2011.