The etiologic, microbiologic, clinical and outcome characteristics of immunocompetent young children <2 years of age hospitalized with acute neutropenia.

BACKGROUND: To describe the etiologic, microbiologic, clinical and outcome characteristics of acute neutropenia (absolute neutrophil count, ANC, <1.5 × 109/L) in hospitalized immunocompetent children. METHODS: Serious bacterial infections (SBI) were defined as culture-positive blood, urine, cerebrospinal fluid, articular fluid or stool infections, alveolar pneumonia, Brucellosis and Rickettsiosis. RESULTS: 431/671 (64.2%) healthy infants and children hospitalized with acute neutropenia were <2 years of age; 176 (40.8%), 167 (38.8%) and 88 (20.4%) patients were aged 0-3, 4-12 and 13-24 months, respectively. There were 19 (4.4%), 53 (12.3%), 140 (32.5%) and 209 (50.8%) patients with ANC count <200, 200-500, 501-1000 and 1001-1500 × 109 cells/L, respectively. Severe neutropenia (<500 × 109/L) was recorded in 72 (16.7%) patients. Fever >38 °C was present in 208/431 (48.3%) patients. Blood cultures were positive in 10 (2.3%), with Brucella melitensis, Staphylococcus aureus and Enterobacter spp. identified in 4, 3 and 2 patients, respectively; 5/10 patients with positive blood cultures were <3 months of age. Overall, 55/431 (12.7%) and 65/431 (15.1%) patients were diagnosed with SBIs and bacterial infections, respectively. Nasal washings-PCR for respiratory viruses was positive in 139/293 (47.4%) patients tested. An infectious etiology (bacterial and/or viral) was diagnosed in 190/431 (44.1%) patients. Three patients were diagnosed with acute lymphocytic leukemia. Resolution of neutropenia was achieved in 111/208 (53.4%) evaluable patients (63%, 50.6% and 48% of patients aged 0-3, 4-12 and >12 months, respectively and 56.8%, 53.5% and 52% of patients with severe, moderate and mild neutropenia, respectively). CONCLUSION: Acute neutropenia is common in immunocompetent children <2 years of age and is frequently associated with viral infections. We showed a substantial involvement of bacterial infections and particularly SBIs in the etiology of acute neutropenia. After a 1-month follow-up, resolution of neutropenia occurred in half of the patients, without association with age subgroups and with neutropenia severity.

Comparison of the etiologic, microbiologic, clinical and outcome characteristics of febrile vs. non-febrile neutropenia in hospitalized immunocompetent children.

We compared the etiologic, microbiologic, clinical, and outcome picture among febrile and non-febrile immunocompetent children hospitalized during 2013-2015 with acute neutropenia (absolute neutrophil count < 1.5 × 109/L). Serious bacterial infections (SBI) were defined as culture-positive blood, urine, cerebrospinal fluid, articular fluid or stool infections, pneumonia, brucellosis, and rickettsiosis. Overall, 664 children < 18 years of age were enrolled; 407 (62.2%) had fever > 38.0 °C and 247 (37.8%) were non-febrile at admission. There were 425 (64.0%), 125 (18.8%), 48 (7.2%), and 66 (9.9%) patients aged 0-24 months, 2-6, 7-12, and > 12 years, respectively. No differences were recorded in the distribution of febrile vs. non-febrile patients among the age groups nor among the 3 neutropenia severity groups (< 0.5, 0.5-1.0 and 1.0-1.5 × 109/L). SBI infections were diagnosed in 98 (14.8%) patients, with higher rates among febrile patients vs. non-febrile patients (16.8% vs. 11.5%, P = 0.06). Brucellosis and rickettsiosis were diagnosed in 15.4% and 23.1% tests performed, respectively. 295/688 (42.9%) virologic examinations returned positive. Among patients < 24 months, more febrile ones had viral infectious compared with afebrile patients (P = 0.025). Acute leukemia was diagnosed in 6 patients. Neutropenia resolved in 163/323 (50.5%) patients during a 1-month follow-up. No differences were recorded in neutropenia resolution between febrile and non-febrile children among all 3 severity groups. Severe neutropenia was rare and occurred mainly in very young patients. SBIs were more common among febrile patients compared with non-febrile patients, but there was no association between severity of neutropenia or its resolution and the presence or absence of fever at diagnosis.