Portal Vein Thrombosis Following Targeted-release Budesonide in IgA Nephropathy and Occult Liver Disease

Targeted-release budesonide (Nefecon) is the first gut–kidney axis–directed therapy for high-risk Immunoglobulin A Nephropathy (IgAN) and relies on intact hepatic first-pass metabolism to limit systemic exposure. We report a 63-year-old man who developed acute portal vein thrombosis within three days of treatment initiation. Imaging demonstrated near-complete thrombosis of the portal venous system. Subsequent evaluation revealed previously unrecognized chronic liver disease, including hereditary hemochromatosis, alcohol use, and early hepatocellular carcinoma without vascular invasion. In conjunction with three previously reported cases of splanchnic vein thrombosis in patients receiving budesonide to treat advanced autoimmune hepatobiliary disease and published pharmacokinetic data, this observation suggests that hepatic dysfunction and disease may lower the thrombotic threshold for budesonide. These findings support careful assessment of hepatic function when initiating targeted-release budesonide in IgAN.