What your doctor is reading on Medscape.com:
MAY 14, 2020 — The COVID-19 pandemic presents myriad challenges to hepatologists, gastroenterologists, transplant programs, primary care providers, and, of course, their patients. These frustrations are compounded by the fact that the virus’ impact on the liver is not yet fully understood.
In order to advise healthcare providers on how best to serve patients and their families during these unprecedented times, the American Association for the Study of Liver Diseases (AASLD) recently released Clinical Insights for Hepatology and Liver Transplant Providers During the COVID-19 Pandemic. The authors of this freely available resource prefaced it with the disclaimer that it represents only their collective opinions and has not been subjected to the methodical rigor of a practice guideline. Instead, it is a “living” document that will evolve and be updated as new information becomes available.
Nonetheless, it offers valuable clinical recommendations and policies to mitigate the impact of the COVID-19 pandemic on patients with liver disease and the healthcare providers who treat them. Here are some of the takeaways that we have found the most useful at our liver care center.
The Novel Coronavirus’ Effects on the Liver: What We Know, What We Don’t
SARS-CoV-2 binds to target cells through a functional receptor, angiotensin-converting enzyme 2, which is present on biliary and liver epithelial cells. Therefore, the liver is a potential target for infection.
Early reports suggest a 14%-53% incidence of liver injury in patients with COVID-19. This estimate is based on observation of elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels 1-2 times the upper limit of normal and modestly elevated total bilirubin levels early in the disease process. Liver injury in mild cases is usually transient and does not require specific treatment. However, rare cases of more severe acute hepatitis have been described. Reports of liver histologic changes have so far been limited, with documented nonspecific injury ranging from focal necrosis to moderate microvesicular steatosis with mild, mixed lobular, and portal activity.
The pathogenesis underlying such abnormal liver biochemistries is undefined. It may reflect a direct virus-induced cytopathic effect and/or immune damage from the provoked inflammatory response (cytokine storm/immune activation).
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It is also not known whether patients with chronic liver disease such as viral hepatitis B and/or C may be more susceptible to liver damage from SARS-CoV-2, as was noted with the earlier SARS-CoV virus. Emerging data do suggest that patients with nonalcoholic fatty liver disease (NAFLD) may be at higher risk for severe COVID-19. It is not clear whether the risk is specific to NAFLD or to coexisting metabolic risk factors such as obesity, cardiovascular disease, and diabetes mellitus, all of which are associated with COVID-19 severity.
Assessing the Risk of COVID-19 in Our Patients
Taking these data into consideration, the AASLD document offers several recommendations.
The authors recommend that immunosuppressed patients (ie, those with autoimmune hepatitis and those post-transplant) should be closely monitored and prioritized for COVID-19 testing.
In addition, it should not be assumed that COVID-19 is the culprit in a patient presenting with acute liver injury. Other causes of elevated AST/ALT levels should be excluded, including viruses such as hepatitis A, B, and C, as well as muscle or cardiac injury, ischemia, and cytokine release syndrome. Similarly, for patients with autoimmune hepatitis or liver transplant recipients with active COVID-19 and elevated AST/ALT levels, do not presume disease flare or acute cellular rejection without biopsy confirmation.
It is also important to keep in mind that proposed COVID-19 therapeutic agents, such as remdesivir and tocilizumab, may in themselves be hepatotoxic.
The need to limit exposure of other patients and caregivers to a patient with COVID-19 is also emphasized. Therefore, transporting COVID-19–positive patients to undergo ultrasound or other advanced imaging should be avoided unless such testing is critical to management planning.