Clinical Characteristics of Severe Neutropenia in Children

Abstract

BACKGROUND: Severe neutropenia is defined as an absolute neutrophil count (ANC) less than 0.5×109/L, which is known to increase the risk of serious bacterial infections. The aim of this study was to investigate characteristics, etiology and differences between transient and chronic severe neutropenia in children. METHODS: 204 children, who were diagnosed with severe neutropenia at the Ajou University Hospital during a 5-year period, were included in the study. Clinical and laboratory features were analyzed. The patients were classified as having transient severe neutropenia (TSN) if recovery occurred within 6 months of diagnosis, and chronic severe neutropenia (CSN) if the neutropenia persisted for 6 months or more. RESULTS: 184 (90.2%) patients with TSN and 20 (9.8%) patients with CSN were identified. Most of the TSN occurred in patients less than 2 year of age (75.5%) and rarely occurred in patients 5 years or older (5.4%). The most common cause of TSN was infection-related neutropenia (82.6%), and most of the associated infections were respiratory infections (44.6%). Compared to TSN, CSN patients were younger at diagnosis (1.00 vs. 0.71, P < 0.001), had a lower ANC at diagnosis (364.8 vs. 214.9, P < 0.001), lower ANC at nadir (356.0 vs. 50.0, P < 0.001), and higher platelet count (188×10⁹ vs. 308×10⁹, P < 0.001), monocyte count (491.5×10⁶ vs. 832.9×10⁶, P=0.010) and CRP (0.22 vs. 0.85, P=0.036). CONCLUSION: Most of the severe neutropenia occurred in children younger than 2 years of age, and virus infection was the most common cause of TSN.