A 46-year-old patient with severe COVID-19 survives due to intensive care with multiple drugs and prolonged artificial ventilation and extracorporeal membrane oxygenation. Four weeks after discharge from intensive care he develops gradually rising liver enzymes; at 6 weeks a consulting hepatologist encounters the following findings: ALT 86 U/l (normal < 38), AST 136 U/l (normal < 35), gamma-glutamyl transferase 17 42 U/l (normal < 50), alkaline phosphatase 2120 U/l (normal < 135). Bilirubin 3.8 mg/dl (normal < 1), Anti-HCV, HBsAg and Anti-HBs are negative. Abdominal ultrasonography reveals a hyperechoic liver, normal size blood vessels and bile ducts, and a normal size spleen.

Which is the likely cause of liver injury in this patient?