The Difference in Clinical Features and Hepatic Injury Characteristics Between Children and Adults With Infectious Mononucleosis

ABSTRACT Aims We aimed to analyze the characteristics of clinical features and hepatic injury characteristics of IM in different age groups. Methods A retrospective study was conducted on IM patients hospitalized in Beijing Youan Hospital, Capital Medical University from July 2015 to July 2025. General data, clinical features, and laboratory information were collected. Results Two hundred patients were enrolled, among them 49.5% were children, and 50.5% were adults. The results indicated that adults had longer fever duration (9 vs. 7 days) and hospitalization days (8 vs. 7 days), a higher proportion of splenomegaly (76.24% vs. 46.46%) and hepatic injury (99.01% vs. 67.68%) (all p < 0.05). Significant differences were observed between the two groups in the level of ALT (368 vs. 90 U/L) and AST (227 vs. 68 U/L) (all p < 0.05). No significant difference was observed between groups regarding gender, maximum temperature, sore throat, decreased appetite, tonsils covered with white membrane, hepatomegaly, hilar lymphadenopathy, leukocytes count, lymphocytes count, CRP, procalcitonin, albumin, EBV‐DNA, short lymph node diameter, CD4+ T cells, and CD8+ T cells (all p > 0.05). Conclusions Both adults and children typically present with the classic triad of IM. However, adults are more prone to prolonged fever, more prominent lymphadenopathy, and an increased incidence of splenomegaly. Hepatic injury is a common complication of IM, occurring with higher incidence and greater severity in adults compared to children; adults more frequently present with concurrent cholestasis and have a predisposition to developing severe liver injury.