Reduction in circulating granulocytes.
Definition typicaly defined by an absolute neutrophil count of less tha 1.5 x 10 to the 9th cell/L.
Mild neutropenia is defined as an absolute neutrophil count of less than 1500 cells per millimeter3.
Moderate neutropenia refers to a count of less than 1000 cells per millimeter3.
Severe neutropenia refers to less than 500 cells per millimeter3.
Occurs as a result of reduced or ineffective production of granulocytes or accelerated removal of granulocytes from the circulation.
Inadequate or ineffective neutrophil production can be due to suppression of myeloid stem cells and from infiltrating bone marrow disorders.
Various drugs can suppress granulocytic precursors.
Ineffective granulopoiesis noted to be related to B12 deficiency, folate deficiency, and myelodysplasia syndromes were cell subject to death in the bone marrow.
Rarely genetic defects can cause impaired granulocytic differentiation.
Immunologically mediated processes may be responsible.
May be caused by splenic sequestration.
Increased peripheral utilization my result in depletion of circulating neutrophils as seen in overwhelming infections of bacterial, fungal or rickettsial diseases.
Drug exposure is responsible form most cases of significant disease.
May be caused by solid tumor malignancies that infiltrate the bone marrow.
May be related to lymphoproliferative malignancies such as hairy cell leukemia, chronic lymphocytic leukemia, and large granular lymphocytic leukemia.
Radiation exposure to multiple bone marrow proliferating sites can cause neutropenia.
May be associated with aplastic anemia, paroxysmal nocturnal hemoglobinuria, rheumatoid arthritis, systemic lupus erythematosus, and May-Hegglin anomaly.
Chemotherapy drugs cause dose-related depression of white blood cell counts.
The Fas ligand mediates apoptosis of neutrophils in large granular lymphocytic leukemia.
Autoimmune neutropenia may be associated with increased levels of circulating anti–neutrophil antibodies with accelerated neutrophil apoptosis.
Viral infections with CMV, EBV, and HIV, etc. may cause neutropenia.
May be associated with parasitic diseases such as malaria.
Hemophagocytosis may be associated with neutropenia and other cytopenias.
Idiosyncratic reaction to drugs can occur and include such agents: aminopyrine, chloramphenicol, sulfonamides, chlorpromazine, phenylbutazone, and thiouracil.
May be related to antibiotics such as penicillin or beta-lactam antibiotics and is immediately reversible on discontinuation.
Genetic predisposition for isolated nature neutropenia may be present and African-Americans.
Cyclic neutropenia has a genetic predisposition to cyclical neutropenia.
A complication is neutropenic colitis, typhlitis.
Phenothiazines can cause toxic manifestations on granulocytic precursors.
Autoantibodies can be directed against neutrophil specific antigens.
Most serious infections result when the neutrophil count is less than 500 cells per mm3.
The duration and magnitude of neutropenia are most important risk factors for the development of invasive fungal infections.
Patients with isolated neutropenia may not have any symptomatology.
Fever maybe the first sign of neutropenia.