COVID-19 related biliary injury: A review of recent literature

Table 1 Liver biopsy and Imaging findings in few previously reported cases of coronavirus disease 2019 cholangiopathy

Ref.	Pathology findings	MRCP
Faruqui et al[5], 2021	Acute and chronic large duct obstruction	Beaded appearance of intrahepatic ducts
	Peri-portal fibrosis	Biliary hyper-enhancement
	Cholestasis
Roth et al[6], 2021	Intra-hepatic ductal beading	Beaded appearance of bile ducts along with segments of strictures and dilation
	Biliary strictures and dilation
	Peri-portal fibrosis
	Cholangiocyte regeneration
	Endothelial swelling of hepatic arteries
Rojas et al[7], 2021	Cholestasis	No biliary obstruction
	Peri-portal inflammation
Daneshjoo et al[22], 2020	Enlarged portal tracts	Prominence of intra and extrahepatic bile ducts
	Bile duct epithelial changes
	Cholestasis, hepatocyte dropout and biliary metaplasia
	Focal biliary infarcts
Tafreshi et al[17], 2021	Bridging fibrosis	Beaded appearance of intrahepatic bile ducts. Periductal prominence
	Cholestasis and cholangiocyte injury	Normal liver parenchyma
	Bile duct proliferation
Lee et al[16], 2021	Bridging fibrosis	Mild intrahepatic ductal dilation
	Onion skinning of bile ducts and cytoplasmic vacuolization of epithelium
	Cholestasis
	Bile duct loss
	Lymphoplasmacytic infiltration
Durazo et al[8], 2021	Degenerative cholangiocyte injury and cytoplasmic vacuolization	Beaded appearance of intrahepatic ducts with multiple segmental strictures
	Intrahepatic microangiopathy
	Hepatic artery endothelial swelling, portal vein phlebitis, sinusoidal obstruction
Cesar Machado et al[23], 2022	Cholangiocyte injury	Multi focal strictures and segmental dilation of intra and extra hepatic bile ducts
	Neutrophilic infiltrate
	Severe cholestasis and fibrosis

MRCP: Magnetic resonance cholangiopancreatography.

Table 2 Proposed mechanisms of coronavirus disease 2019 cholangiopathy

No.	Proposed pathogenesis of COVID-19 cholangiopathy
1	Cholangiocyte necrosis because of bile duct ischemia[24,25]
2	Micro thrombosis of hepatic sinusoids and ischemic injury[6]
3	Inflammation triggered due to cytokine release (cytokine release syndrome)
4	Direct virus mediated damage[11]
5	Drug induced liver injury in setting of severe COVID-19 infection (antibiotics, Remdesivir among others)
6	Ketamine related cholangiopathy in setting of COVID-19[14]

COVID-19: Coronavirus disease 2019.