TBA (22W130)

Acute severe hepatitis of unknown aetiology in children

Author(s)

Fallon Verbruggen, T (1); Egan, R (1); Crothers, E (1); Ring, C (1); Hayden, J (1); Hagan, R (2); Cotter, S (3); De Gascun, C (4); Hussey, S (1); Bourke, B (1); Broderick, A (1); Quinn, S (1); Dunne, C (1) and Fitzpatrick, E (1)

Department(s)/Institutions

(1) National Paediatric Liver Service, Children's Health Ireland at Crumlin, Ireland (2) Irish Blood Transfusion Service (3) Health Protection and Surveillance Centre, Ireland (4) National Virus Reference Laboratory, Ireland

Introduction

Acute severe hepatitis of unknown aetiology, also known as non-A to E hepatitis or seronegative hepatitis is a common cause of paediatric acute liver failure (PALF).

Aims/Background

While true incidence of this condition is unknown, a dramatic increase in cases was first reported in Scotland on April 5th 2022. As of September 29th, 555 cases have been reported in Europe with a total of more than 1000 world-wide.

Method

This is a retrospective review of children referred to the National Paediatric Liver Service in Ireland between January and August 2022. Children were less than 10 years of age at presentation and had a new acute hepatitis (AST and/or ALT of >500 IU/L).

Results

27 children (15 females) met the case definition. The majority were previously healthy children with a median age of 3 years and 11 months (interquartile range 2 years 8 months to 5 years 2 months). The most common features at presentation were jaundice (85%), lethargy (67%), abdominal pain (62%) and acholic stools or dark urine (55%). Median peak AST was 2464 IU/L (interquartile range 1597 – 4315 IU/L). 21 (78%) children were PCR positive for either adenovirus or Human Herpes Virus-7 (HHV-7) in blood at presentation. HLA subtyping in 22 children tested to date revealed an allele frequency of 34.1% for DRB1*04:01 (Irish blood donor allele frequency is 20%) and 4.5% for DRB1*04:07 (control 2.4%). 5 (19%) children met criteria for PALF of whom 2 required liver transplantation.

Conclusions

Ireland experienced a significant and unprecedented epidemic of acute severe hepatitis in children this year. The majority had either adenovirus or HHV-7 though at low levels at the time of presentation. HLA typing suggested a possible predisposition to autoimmunity in 14/22 (60%). Further studies into the pathogenesis and aetiology of this outbreak are ongoing.