Case report: A rare case of IgA nephropathy associated with type II Abernethy malformation

Abernethy malformation is a rare congenital vascular anomaly involving extrahepatic portosystemic shunting, with only a handful of reported cases coexisting with IgA nephropathy. We present a case of a patient who initially manifested with proteinuria and hematuria, and later developed hepatic encephalopathy, prompting vascular imaging that identified a type II Abernethy malformation characterized by an extrahepatic portocaval shunt. A diagnosis of type II Abernethy malformation was established. The patient underwent laparoscopic partial shunt disconnection, which led to a marked reduction in proteinuria (from 0.8-2.1 g/d to 0.19-0.29 g/d). This case, along with previous reports, suggests that portosystemic shunting in Abernethy malformation may be a pathogenic factor in IgA nephropathy. Surgical correction of the shunt may confer renal benefits in selected cases and deserves further investigation.