Medical Definition of Neutrophil. Neutrophil: A type of white blood cell, a granulocyte that is filled with microscopic granules, little sacs containing enzymes that digest microorganisms. Also known as polymorphonuclear leukocyte or poly.
Definition of Neutropenia. Neutropenia: Not enough neutrophils, neutrophils being a type of white blood cell (specifically a form of granulocyte) filled with neutrally-staining granules, tiny sacs of enzymes that help the cell to kill and digest microorganisms it has engulfed by phagocytosis.
Neutropenia: Causes, Diagnosis and Treatment. Neutropenia is characterized by a significant reduction in neutrophils, an essential first line of defense against infections. The main complication of neutropenia is the increased risk of an infection and the lack of resources to fight it off. There are a number of causes of neutropenia including nutrient deficiency and genetic disorders.