Definition and Etiology
The term is derived from leukemia and -eides (resembling). It refers to shifts in the blood system and hematopoietic organs that prompt clinicians to suspect hemoblastosis. However, these conditions are strictly reactive and never transform into the pathology they mimic.
The main causes of such conditions include:
- various infections;
- marked intoxications;
- neoplastic processes;
- tumor metastasis to the bone marrow.
Mechanisms of Development
The alterations in blood and bone marrow are based on three key pathogenetic mechanisms:
- Accelerated and premature release of immature cellular elements into the bloodstream.
- Significantly increased production of new blood cells.
- Restriction of the physiological egress of formed cells from the blood back into the tissues.
It is worth noting that these processes can affect both the peripheral blood and the bone marrow tissue itself.
Differential Diagnosis with Hemoblastoses
A critical point in clinical practice is distinguishing reactive changes from true blood malignancies. Leukemoid reactions are characterized by the following features:
- Association with a Trigger: There is always an underlying primary disease that provoked the shift in laboratory parameters.
- Clinical Presentation: The patient's general condition strictly reflects the severity of this primary condition.
- Laboratory Parameters: Basophil and platelet counts usually remain within normal limits, while leukocyte alkaline phosphatase (LAP) activity is normal or decreased.
- Cytogenetics: Complete absence of the Philadelphia chromosome and other karyotypic abnormalities in the bone marrow.