Risk factors for persistent fever in children with infectious mononucleosis

Fever is a common symptom in children with infectious mononucleosis (IM). However, the significance of the duration of a fever is poorly understood. This study aimed to analyze the risk factors for persistent fever in children with IM.

Patients diagnosed with IM (aged <18 years; except those with concomitant hematological malignancies or tumor diseases) in a high-volume academic hospital in 2019 were reviewed from a prospectively maintained database. Children with transient fever (≤7 days) were compared with those with persistent fever (>7 days). The risk factors for persistent fever in children with IM were examined using binary logistic regression. Furthermore, the predictive ability of these risk factors was assessed and presented using a receiver operating characteristic (ROC) curve.

Of the 184 children included in this study, 131 (71.96%) belonged to the transient fever group and 53 (28.04%) belonged to the persistent fever group (median age: 49 and 64 months, respectively; p = 0.093). Statistical significance was observed in hepatomegaly, alanine aminotransferase level, blood triglyceride level, and blood Epstein-Barr virus polymerase chain reaction (EBV-PCR) copy number (all p < 0.05). Binary logistic regression revealed that high blood triglyceride level was the risk factor for persistent fever in children with IM. High blood triglyceride level predicted persistent fever duration with an area under the ROC curve of 0.73 and an optimal cutoff value of 1.315 mmol/L.

High blood triglyceride level was the risk factor for persistent fever in children with IM. Thus, children with elevated levels of blood triglycerides need additional care. To diagnose IM, a blood EBV-PCR is more useful than a throat-swab EBV-PCR.