Sharma et al. describe patency of the ductus venosus (DV) associated with Enterovirus sp. infection (EVI) and acute liver failure (ALF) in a neonate, reporting lessened hyperbilirubinemia and hyperammonemia after DV occlusion. What led to DV patency?
Although no liver biopsy specimen was examined by microscopy for the infant reported by Sharma et al., EVI can cause a florid and necrotizing neonatal hepatitis. Lobular disarray, with hepatocyte swelling, intrasinusoidal thrombosis, and even a veno-occlusive component, likely raises intrahepatic resistance to blood flow. The DV, as a shunt, relieves pressure within the portal circulation.
Substantial liver scarring and cirrhosis often develop before birth in neonatal hemochromatosis (NH). The clinicopathological picture of NH thus actually reflects acute decompensation (prompted by the withdrawal of placental support) of chronic liver disease, but the clinical picture may be that of ALF. The phenotype of NH can be found in perinatal EVI.[3, 4] NH is associated with DV patency, which has been ascribed to intrahepatic resistance to blood flow; liver disease in children with NH has been misattributed to DV patency.
For Sharma et al.'s patient, the combination of supportive care and DV occlusion was associated with an improvement in clinical-biochemistry test results. Perhaps clearance of viral infection and lessened lobular disarray both contributed to this improvement and led to a fall in intrahepatic resistance to blood flow. The latter, in turn, may have facilitated DV occlusion.
Liver disease with established intralobular fibrosis, as found in NH, might respond poorly to mechanical obstruction of the DV lumen. In a neonate with ALF and a patent DV, even if EVI is documented, it may be prudent to consider NH as possibly responsible for DV patency and to determine whether the liver is scarred before DV occlusion is attempted.
A.S. Knisely, M.D.
Institute of Liver Studies
King's College Hospital
London, United Kingdom