Transaminase levels reflect disease severity in children ventilated for respiratory syncytial virus (RSV) bronchiolitis

Bronchiolitis, often caused by respiratory syncytial virus (RSV), is the commonest cause of hospitalisation in infancy. Serum transaminases are sometimes raised in children with bronchiolitis. We tested the hypothesis that raised transaminases are associated with increased disease severity in children ventilated for bronchiolitis. Prospective observational cohort study of mechanically ventilated children with community-acquired RSV bronchiolitis. Alanine transaminase (ALT) and aspartate transaminase (AST) levels were measured daily. Children with normal transaminases were compared with those with elevated levels. Over 11 consecutive winters, 556 children with RSV bronchiolitis were mechanically ventilated – 226 had comorbidities and therefore excluded; 313 of remaining 330 were under 2 years age; 305 had early transaminase measurements. 57/305 (19%) had elevated transaminase (AST and/or ALT) levels. For the first time we show that duration of ventilation and length of admission were both significantly longer, and paediatric index of mortality and C-reactive protein higher, in those with elevated AST levels on admission (but not those with elevated ALT levels). Furthermore, transaminase elevations were transient, generally having normalised by seven days following admission. RSV bronchiolitis was more severe in children with early elevated AST levels and could be used early in the illness as a predictor for disease severity.