WHAT NEUTROPENIA IS ?

ΟΥΔΕΤΕΡΟΠΕΝΙΑ

• Μείωση των κυκλοφορούντων πολυμορφοπυρήνων
• Ήπια = απόλυτος απόλυτος αριθμός κυττάρων 1000-1500/µL
• Μέτρια = απόλυτος απόλυτος αριθμός κυττάρων 500-1000/µL
• Σοβαρή = απόλυτος απόλυτος αριθμός κυττάρων κάτω από 500/µL
• Ακοκιοκυττάρωση = ουσιαστικά απουσία ουδετεροφίλων στο περιφερικό αίμα (συνήθως ο όρος χρησιμοποιείται αν κύτταρα κάτω από 100/μL)
• Κύρια συνέπεια της ουδετεροπενίας οι λοιμώξεις, με συχνότερες αυτές από τους βλεννογόνους
• source: Loimoxi blog

Neutropenia

Neutropenia is a decrease in circulating neutrophils in the nonmarginal pool, which constitutes 4-5% of total body neutrophil stores. Most of the neutrophils are contained in the bone marrow, either as mitotically active (one third) or postmitotic mature cells (two thirds).  Granulocytopenia is defined as a reduced number of blood granulocytes, namely neutrophils, eosinophils, and basophils. However, the term granulocytopenia is often used synonymously with neutropenia and, in that sense, is again confined to the neutrophil lineage alone.
Neutropenia is defined in terms of the absolute neutrophil count (ANC). The ANC is calculated by multiplying the total white blood cell (WBC) count by the percentage of neutrophils (segmented neutrophils or granulocytes) plus the band forms of neutrophils in the complete blood count (CBC) differential.
Note that many modern automated instruments actually calculate and provide the ANC number in their reports. These instruments do not analyze separately bands from segmented neutrophils, and so the combined number is termed the absolute neutrophil count (ANC), representing both bands and more mature segmented neutrophils. If a band number is reported separately, usually by smear review, then one can divide the ANC into bands and segmented neutrophils by subtracting the absolute band number from the total ANC.
 

The lower limit of the reference value for ANC in adults varies in different laboratories from 1.5-1.8 10⁹/L or 1500-1800/µL (mm³). For practical purposes, a value lower than 1500 cells/µL is generally used to define neutropenia. Age, race, genetic background, environment, and other factors can influence the neutrophil count. For example, blacks may have a lower but normal ANC value of 1000 cells/µL, with a normal total WBC count.

                          Neutropenia is classified as mild, moderate, or severe, based on the ANC. Mild neutropenia is present when the ANC is 1000-1500 cells/µL, moderate neutropenia is present with an ANC of 500-1000/µL, and severe neutropenia refers to an ANC lower than 500 cells/µL. The risk of bacterial infection is related to both the severity and duration of the neutropenia.
The term agranulocytosis is used to describe a more severe subset of neutropenia. Agranulocytosis refers to a virtual absence of neutrophils in peripheral blood. It is usually applied to cases in which the ANC is lower than 100/μL. The reduced number of neutrophils makes patients extremely vulnerable to infection.Cardinal symptoms include fever, sepsis, and other manifestations of infection. Causes can include drugs, chemicals, infective agents, ionizing radiation, immune mechanisms, primary bone marrow failure syndromes, and heritable genetic aberrations.
Some cases, such those from benign familial neutropenia, are characterized by only mild neutropenia and are of no obvious significance for health.  This article is limited to discussing neutropenia (ANC <1500/µL) and agranulocytosis (ANC <100/µL). It does not address the transient neutropenia associated with cancer chemotherapy, nor does it consider agranulocytosis occurring as part of primary marrow-failure syndromes (eg, aplastic anemia, pancytopenia, acute leukemia, myelodysplastic syndromes).
SOURCE :Medscape