Successful Living Related Kidney Transplant Alone in a Patient with Noncirrhotic Portal Hypertension

Introduction: Kidney transplantation alone in patients with portal hypertension remains under explored in medical literature. It is generally accepted to avoid isolated kidney transplantation in patients with decompensated cirrhosis. We present a case of successful kidney transplantation alone in a patient with Azathioprine (AZA) induced sinusoidal obstruction syndrome (SOS) and portal hypertension. Case Description: A 54-year-old man with a history of Crohn’s colitis developed IgA nephropathy that was treated with AZA and prednisone for 3 years. His kidney function worsened, accompanied by ascites, splenomegaly, and portal hypertension. Abdominal imaging revealed a cirrhotic appearing liver. AZA was stopped due to pancytopenia. Despite progression to ESKD and initiation of dialysis (HD) with ultrafiltration, he required regular large volume paracenteses (LVP). He was referred for SLK evaluation. During his workup, he underwent a liver biopsy revealing sinusoidal obstruction without hepatic fibrosis, consistent with SOS. His measured portosystemic pressure gradient was elevated at 15 mmHg. His SOS was attributed to a rare side-effect of AZA. Due to the absence of hepatic fibrosis, he was deemed not a liver transplant candidate. Nine months following AZA discontinuation and continued HD, he no longer required LVP. However, portal gradient pressures remained elevated at 16 mmHg. Despite reservations due to his portal pressure, he successfully underwent a living donor kidney transplant from an HLA identical sibling, and post-transplant, his ascites resolved. Since the transplant, the patient is without symptoms or complications from liver disease or portal hypertension. Discussion: In this case, the patient had portal hypertension related to SOS, not cirrhosis. With diligence to his volume management and discontinuation of AZA, this patient underwent successful kidney-alone transplantation. AZA-induced SOS is a rare complication. The mechanism of injury is unclear, though it is suggested that glutathione depletion triggers the inflammatory cascade resulting in thrombosis and fibrosis in the hepatic microvasculature causing SOS and portal hypertension. The number of reported cases remains low, although a case series of kidney transplant patients found a 2.5% occurrence of SOS attributed to AZA.