Etiology of Neutropenia Acute neutropenia (occurring over hours to a few days) can develop as a result of Rapid neutrophil use or destruction Impaired neutrophil production Chronic neutropenia (lasting months to years) usually arises as a result of Reduced production Excessive splenic sequestration Neutropenia also may be classified as Primary due to an intrinsic defect in marrow myeloid cells Secondary due to factors extrinsic to marrow myeloid cells See also the table Classification of Neutropenias.