Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 19 (COVID-19), emerged in Wuhan, China has become a pandemic affecting every country in the world. It has been estimated that by October 1, 2020, more than 34 million people have been infected and more than a million have died of corona virus. Patients who are at increased risk for severe illness requiring hospitalization are those that are older and those with comorbidities including obesity, diabetes, and heart disease.

The most common complication reported is acute respiratory distress syndrome and sepsis, however, various extrapulmonary manifestations including injury to the central nervous system, heart, kidneys, and the liver were also found. A trial demonstrated that 3.6% of patients with COVID-19 had preexisting chronic liver disease, however, only 23% had increased liver enzyme tests at presentation. After a follow-up period, a further 24% showed increased levels of liver enzyme. Thus, it was concluded that patients with liver injury are at higher risk for severe COVID-19 disease, yet a causal association has not been established.

A study published in the issue of Cellular and Molecular Gastroenterology and Hepatology, Fiel et al revealed the findings of two liver biopsies performed on patients with COVID-19 without substantial complicating lung disease. One of the patient was a 63-year-old post–liver transplant patient had acquired a SARS-CoV-2 infection while in a rehabilitation facility recovering from a stroke. His risk factors associated with severe COVID-19 also included chronic renal failure, hypertension, and diabetes mellitus. While admission, he developed abnormal liver enzymes, initially with elevated alanine aminotransferase to 1761 U/L followed by an increasing bilirubin and an alkaline phosphatase level of 1568 U/L. A liver biopsy was done to assess the cause of the liver injury, which represented an acute hepatitis superimposed on acute cellular rejection. The biopsy also showed significant bile duct injury. In situ hybridization recognized viral RNA in uncommon cells and ultrastructural examination revealed apparent viral particles within cells. 

Thus, liver biopsy should be conducted when the hepatic injury is a predominant clinical feature or when alternative causes of injury need to be excluded, as it offers better localization of cellular injury and overall severity in comparison to non-invasive methods. Such biopsies should be supplemented with ancillary techniques to detect the virus in situ and to better elucidate the mechanism via which SARS-CoV-2 affects the liver. 

Source:Kleiner DE. Liver Biopsy Shines a Light on COVID-19-Related Liver Injury. Cell MolGastroenterolHepatol. 2021; 11(3): 881–882.