Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content ++ NEUTROPENIA ++ Leukopenia refers to a reduced total leukocyte count. Granulocytopenia refers to a reduced granulocyte (neutrophils, eosinophils, and basophils) count. Neutropenia refers to a reduced neutrophil count: less than 1.5 × 109/L in patients from age 1 month to 10 years, and less than 1.8 × 109/L in patients older than age 10 years. Table 31–1 outlines the classification of neutrophil disorders. Agranulocytosis literally means a complete absence of blood granulocytes but is used to indicate very severe neutropenia, usually a neutrophil count < 0.5 × 109/L. Americans of African descent (as do some other ethnic groups) have lower mean neutrophil counts than do Americans of European descent. The risk of infections is inversely related to the severity of the neutropenia: patients with qualitatively normal neutrophils and neutrophil counts of 1.0 to 1.8 × 109/L are at little risk; patients with counts of 0.5 to 1.0 × 109/L are at low or slight risk; and patients with counts less than 0.5 × 109/L are at higher risk. Patients with severe, prolonged neutropenia are at particular risk for bacterial and fungal infections. The risk is calculated not only by the neutrophil count but by complicating factors as follows: — The longer the duration of severe neutropenia, the greater the risk of infection. — The risk of infection is greater when the count is falling rapidly or when there is associated monocytopenia, lymphocytopenia, or hypogammaglobulinemia. — Neutropenia caused by disorders of hematopoietic progenitor cells (e.g., chemotherapy-induced marrow suppression, severe inherited neutropenia) generally results in a greater susceptibility to infections compared with neutropenia resulting from accelerated turnover (e.g., immune neutropenia). — Integrity of the skin and mucous membranes, blood supply to tissues, presence of an indwelling catheter, and nutritional status are also important in considering infection risk. Neutropenia can be classified as: (1) disorders of production; (2) disorders of distribution and turnover; (3) drug-induced neutropenia; and (4) neutropenia with infectious diseases. ++ DISORDERS OF PRODUCTION ++ Inherited Neutropenia Syndromes ++ Kostmann Syndrome ++ Can be an autosomal dominant (mutation in gene for neutrophil elastase, ELA-2), recessive (mutation in gene encoding mitochondrial protein, HAX-1)), or a sporadic (mutation in ELA-2) disease. Mutation in the gene for the glucose-6-phosphate catalytic subunit (G6PC3) also can cause severe neutropenia. Mutations in the receptor for granulocyte colony-stimulating factor (G-CSF) and in RAS may be present but are not the cause of the neutropenia but may predispose to evolution to acute myelogenous leukemia. Otitis, gingivitis, pneumonia, enteritis, peritonitis, and bacteremia usually occur in the first month of life. Neutrophil count is often less than 0.2 × 109/L. Eosinophilia, monocytosis, and mild splenomegaly may be present. Marrow usually shows some early neutrophil precursors but few myelocytes or mature neutrophils. Immunoglobulin levels are usually normal or increased and chromosome analyses are normal. Treatment with ... GET ACCESS TO THIS RESOURCE Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth Get Free Access Through Your Institution Contact your institution's library to ask if they subscribe to McGraw-Hill Medical Products. What is MyAccess? Create a FREE MyAccess profile to: Use this site remotely Bookmark your favorite content Track your self-assessment progress and more!