A Review on Chronic Neutropenia of the Adult: Emerging Clinical Dilemmas

Abstract

Neutropenia is defined by a decrease of the absolute neutrophil counts (ANCs) below the threshold of 1.8x10⁹/L in the Caucasians and 1.5x10⁹/L in people of African origins. This is valid from 1 year of age until adulthood, as the cut off for normality would be 1x10⁹/L in newborns and children <1 year of age.¹ Neutropenia is considered chronic if persists longer than 3 months, and is usually graded into mild (ANCs 1-1.5x10⁹/L), moderate (ANCs 0.5-1 x10⁹/L), and severe forms (ANCs<0.5 x10⁹/L).¹ The condition is further classified into congenital and acquired, and the latter in primary and secondary forms.² Neutropenia cause is often obscure, particularly in adults, where idiopathic neutropenia is one of the most frequent reasons for hematologic referral. Moreover, the general practitioner and the hematologist himself can find it difficult to orientate among emerging clinical dilemmas: how much one should worry about moderate/mild forms? What tests to perform? Which is the priority for visits and workup? Once excluded oncologic and common secondary forms, how will I follow a patient with chronic idiopathic disease? Thereafter, we will focus on the available literature on acquired neutropenia of the adult and provide some practical advice for patient’ evaluation and follow up in the clinical practice.