TY - CHAP M1 - Book, Section TI - Neonatal Neutropenia A1 - Hsu, Christopher H. A1 - Jeng, Michael R. A2 - Stevenson, David K. A2 - Cohen, Ronald S. A2 - Sunshine, Philip Y1 - 2015 N1 - T2 - Neonatology: Clinical Practice and Procedures AB - The neutrophil is a myeloid-derived white blood cell important in combating bacterial and fungal infections. For a more detailed discussion of neutrophil development and immunologic function, refer to chapters 49 and 51. Most neutrophil abnormalities in the neonate involve quantitative disorders of the neutrophil, with the vast majority of clinical issues involving decreased neutrophil counts or neutropenia. Neutropenia is defined as an absolute neutrophil count (ANC) less than 1500/mm3. In a newborn, there can be many causes, some acquired with expected resolution, such as increased utilization of neutrophils with low marrow reserve or failures of production or release from the bone marrow, or there can be congenital causes, which are expected to be lifelong. The patient may have different clinical presentations depending on the etiology. Because of the low neutrophil reserve (capacity to produce neutrophils) in the bone marrow, the neonate is especially prone to development of neutropenia. Differentiating the etiology of neutropenia in an infant is therefore dependent on thorough knowledge of the maternal (both pregnancy and delivery) and neonatal history, as well as the physical examination of the infant, in conjunction with appropriate laboratory tests. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accesspediatrics.mhmedical.com/content.aspx?aid=1109799483 ER -