Clinical implications of aminotransferase elevation in hospitalised infants aged 8‐90 days with respiratory virus detection

Background Fever and respiratory symptoms are the major causes of hospitalisation in infants aged 90 days or less. Respiratory viruses (RVs) are detected by multiplex reverse transcriptase‐polymerase chain reaction (mRT‐PCR) in up to 70% of infants tested in this population. Aminotransferase elevation is not uncommon in RV infections, and repeat laboratory investigations are frequent due to concerns regarding the occurrence of hepatic disease. Methods This retrospective observational cohort study included 271 infants aged 8‐90 days, with positive RV mRT‐PCR results. Data were obtained on demographics, laboratory results and final diagnoses of hepatobiliary disease. Results Fever (73.1%) and/or respiratory symptoms (75.6%) were the major presentations among the hospitalised infants. Aspartate aminotransferase (AST) or alanine aminotransferase (ALT) levels were elevated in 62 (22.9%) of the 271 infants. Twenty‐four of these 62 infants had their first follow‐up, and 19 (79.2%) showed persistent elevation. All 10 (100%) infants who had their second follow‐up showed persistently elevated aminotransferase levels. Eventually, none of the 10 infants were diagnosed with hepatic disease during the median follow‐up of 10 days (range 3‐232 days). Among the RVs of interest, parainfluenza virus type 1 was significantly associated with aminotransferase elevation (odds ratio: 2.95; 95% confidence interval [CI]: 1.11‐7.83). Conclusions RV‐related non‐specific hepatitis is occasionally observed in infants aged 8‐90 days, and ALT elevation is the most common abnormality. However, a final diagnosis of primary hepatobiliary disease appears to be rare. Therefore, regular follow‐ups and targeted testing may be recommended in this specific population.