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World J Hepatol. Dec 27, 2021; 13(12): 2013-2023
Published online Dec 27, 2021. doi: 10.4254/wjh.v13.i12.2013
COVID-19 and the liver: A brief and core review
Bircan Kayaaslan, Rahmet Guner
Bircan Kayaaslan, Rahmet Guner, Department of Infectious Disease and Clinical Microbiology, Ankara City Hospital, Ankara Yildirim Beyazit University, Ankara 06800, Turkey
Author contributions: Kayaaslan B contributed to conception and design of the review and writing of the manuscript; Guner R contributed to review and editing of the manuscript.
Conflict-of-interest statement: The authors declare having no conflicts of interest.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Bircan Kayaaslan, MD, Associate Professor, Department of Infectious Disease and Clinical Microbiology, Ankara City Hospital, Ankara Yildirim Beyazit University, No. 1 Bilkent street, Çankaya District, Ankara 06800, Turkey. drbican@gmail.com
Received: May 18, 2021
Peer-review started: May 18, 2021
First decision: June 15, 2021
Revised: June 23, 2021
Accepted: November 27, 2021
Article in press: October 27, 2021
Published online: December 27, 2021
Processing time: 222 Days and 9.7 Hours
Abstract

Coronavirus disease 2019 has a wide range of clinical spectrum from asymptomatic infection to severe infection resulting in death within a short time. Currently, it is known that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) does not only cause a respiratory tract infection but a more complicated disease that can lead to multiple system involvement including the liver. Herein, we evaluate the epidemiology, the impact of liver injury/ dysfunction on disease prognosis, the pathophysiological mechanisms and management of liver injury. More than one-fourth of the patients have abnormal liver function tests, mostly a mild-to-moderate liver dysfunction. Liver injury is significantly associated with a poor clinical outcome. Direct cytotoxic effect of SARS-CoV-2, the immune response (“cytokine storm”), the complications related to the disease, and drugs used in the treatments are the pathophysiological mechanisms responsible for liver injury. However, the exact mechanism is not yet clearly explained. The binding of SARS-CoV-2 to the angiotensin-converting enzyme 2 receptors and entering the hepatocyte and cholangiocytes can cause cytotoxic effects on the liver. Excessive immune response has an important role in disease progression and causes acute respiratory distress syndrome and multi-organ failures accompanied by liver injury. Treatment drugs, particularly lopinavir/ritonavir, remdesivir and antibiotics are a frequent reason for liver injury. The possible reasons should be meticulously investigated and resolved.

Keywords: COVID-19; SARS-CoV-2; Liver injury; Liver dysfunction; Chronic liver disease; Pathophysiology

Core Tip: The study evaluated the incidence of liver injury in coronavirus disease 2019 (COVID-19) patients and its impact on clinical outcomes and pathophysiological mechanism of liver injury. More than one-fourth of COVID-19 patients had suffered from liver injury, mostly a mild-to-moderate liver dysfunction. Liver involvement is independently associated with adverse clinical outcomes. Direct viral cytotoxic effect, complications of the disease, and drugs used in the treatments are the pathophysiological mechanisms suggested for liver injury. However, the exact mechanism was not clearly explained. The actual cause should be carefully investigated in the presence of abnormal liver function tests, and appropriate treatments provided for possible factors.