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For further information, see CMDT Part 15-22: Neutropenia
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Essentials of Diagnosis
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General Considerations
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Patients with neutropenia are vulnerable to gram-positive and gram-negative bacterial and fungal infections
Risk of infection is related to the severity of neutropenia
Patients with "chronic benign neutropenia" are free of infection despite very low stable neutrophil counts
In patients with cyclic neutropenia, the neutrophil count oscillates (usually in 21-day cycles) between normal and low, with infections occurring during the nadirs
Congenital neutropenia is lifelong neutropenia punctuated with infection
Both cyclic neutropenia and congenital neutropenia represent problems in mutations in the neutrophil elastase gene ELANE (also called ELA-2)
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A variety of bone marrow disorders and non-marrow conditions may cause neutropenia (Table 15–12)
All the causes of aplastic anemia and pancytopenia may cause neutropenia
New onset of an isolated neutropenia is most often due to an idiosyncratic reaction to a drug
Agranulocytosis (complete absence of neutrophils in the peripheral blood) is almost always due to a drug reaction
Neutropenia in the presence of a normal bone marrow may be due to
Isolated neutropenia is an uncommon presentation of hairy cell leukemia or a myelodysplastic neoplasm
Myelosuppressive cytotoxic chemotherapy causes neutropenia in a predictable manner
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