High Incidence of Secondary Sclerosing Cholangitis in Hospitalized "First-wave" COVID-19 Patients: a Retrospective Single Center Study

In Central Europe, the first wave of SARS-CoV-2 peaked in April 2020 and ended in June 2020. Our tertiary care center, the University Hospital of Tübingen is located in a first-wave SARS-CoV-2 hotspot area that had the second highest 7-day incidence in Germany on March 31, 2020, exactly at the peak of the first wave in Germany (205.9/100,000, www.rki.de; the peak daily incidence in Tübingen was 179/100,000 on March 25, 2020). In this period, 249 patients were hospitalized for or with SARS-CoV-2 infection.

To gain fast knowledge about the new disease, a COVID-19 patient registry was established at our center, including all patients admitted to Tübingen University Hospital for or with SARS-CoV-2 infection and retrospectively collecting routine clinical data. After hospitalization, patients were followed up in the outpatient clinic of our department, the Department of Gastroenterology, Hepatology, Gastrointestinal Oncology, Geriatrics and Infectious Diseases.

Subsequently, several patients with secondary sclerosing cholangitis (SSC) after COVID-19 (SSC-COVID) were recognized in our center, either from our own cohort, or referred to our center due to the need for further treatment of end-stage liver disease including liver transplantation. SSC is a cholangiopathy estimated to be rare in ICU patients with an incidence of 1/2000 ICU patients. Pathogenesis has not been fully deciphered, but a combination of ischemic injury and increased bile toxicity during critical illness is suspected. This imposes acute damage on the biliary system, that, if not resolving early or spontaneously, may lead to the vicious circle of gradually destruction of the biliary tree over time, well known to hepatologists and endoscopists.