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World J Gastroenterol. Dec 21, 2022; 28(47): 6662-6688
Published online Dec 21, 2022. doi: 10.3748/wjg.v28.i47.6662
Acute liver injury in COVID-19 patients hospitalized in the intensive care unit: Narrative review
Effie Polyzogopoulou, Pinelopi Amoiridou, Theodore P Abraham, Ioannis Ventoulis
Effie Polyzogopoulou, Department of Emergency Medicine, Attikon University Hospital, National and Kapodistrian University of Athens Medical School, Athens 12462, Greece
Pinelopi Amoiridou, Department of Intensive Care, AHEPA University Hospital, Thessaloniki 54621, Greece
Theodore P Abraham, Hypertrophic Cardiomyopathy Center of Excellence, University of California, San Francisco, CA 94117, United States
Ioannis Ventoulis, Department of Occupational Therapy, University of Western Macedonia, Ptolemaida 50200, Greece
Author contributions: Ventoulis I conceived and designed the study; Amoiridou P and Polyzogopoulou E contributed to the data acquisition, analysis and interpretation, drafted the manuscript with input from Abraham TP and Ventoulis I; Polyzogopoulou E contributed to the final layout of the table and figures; Abraham TP performed language editing of the manuscript; Abraham TP and Ventoulis I performed editing and critical revision of the manuscript; Polyzogopoulou E, Amoiridou P, Abraham TP and Ventoulis I approved the final version of the article.
Conflict-of-interest statement: All the authors report no relevant conflicts of interest for this article.
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:
Corresponding author: Ioannis Ventoulis, MD, PhD, Assistant Professor, Department of Occupational Therapy, University of Western Macedonia, Keptse Area, Ptolemaida 50200, Greece.
Received: September 13, 2022
Peer-review started: September 13, 2022
First decision: October 19, 2022
Revised: November 14, 2022
Accepted: December 5, 2022
Article in press: December 5, 2022
Published online: December 21, 2022

In recent years, humanity has been confronted with a global pandemic due to coronavirus disease 2019 (COVID-19), which has caused an unprecedented health and economic crisis worldwide. Apart from the respiratory symptoms, which are considered the principal manifestations of COVID-19, it has been recognized that COVID-19 constitutes a systemic inflammatory process affecting multiple organ systems. Across the spectrum of organ involvement in COVID-19, acute liver injury (ALI) has been gradually gaining increasing attention by the international scientific community. COVID-19 associated liver impairment can affect a considerable proportion of COVID-19 patients and seems to correlate with the severity of the disease course. Indeed, COVID-19 patients hospitalized in the intensive care unit (ICU) run a greater risk of developing ALI due to the severity of their clinical condition and in the context of multi-organ failure. The putative pathophysiological mechanisms of COVID-19 induced ALI in ICU patients remain poorly understood and appear to be multifactorial in nature. Several theories have been proposed to explain the occurrence of ALI in the ICU setting, such as hypoperfusion and ischemia due to hemodynamic instability, passive liver congestion as a result of congestive heart failure, ischemia-reperfusion injury, hypoxia due to respiratory failure, mechanical ventilation itself, sepsis and septic shock, cytokine storm, endotheliitis with concomitant coagulopathy, drug-induced liver injury, parenteral nutrition and direct cytopathic viral effect. It should be noted that no specific therapy for COVID-19 induced ALI exists. Therefore, the therapeutic approach lies in preventive measures and is exclusively supportive once ALI ensues. The aim of the current review is to scrutinize the existing evidence on COVID-19 associated ALI in ICU patients, explore its clinical implications, shed light on the underlying pathophysiological mechanisms and propose potential therapeutic approaches. Ongoing research on the particular scientific field will further elucidate the pathophysiology behind ALI and address unresolved issues, in the hope of mitigating the tremendous health consequences imposed by COVID-19 on ICU patients.

Keywords: Liver injury, COVID-19, Intensive care, Pathophysiological mechanisms, Cytokine storm, Multi-organ failure

Core Tip: In recent times, coronavirus disease 2019 (COVID-19) pandemic has substantially altered the hitherto existing medical landscape, causing tremendous perturbations among the global scientific community and imposing a disproportionate burden on healthcare systems worldwide. It soon became apparent that COVID-19 affects multiple organ systems, including the liver. Acute liver injury has been progressively identified as a common, yet often under-recognized, complication of COVID-19, especially in the intensive care unit (ICU) setting, resulting in higher mortality rates. This review attempts to elucidate the underlying pathophysiological mechanisms that contribute to the development of acute liver injury in ICU patients with COVID-19, summarize emergent data and propose therapeutic strategies.