A 23-year-old man with pre-B ALL who had an allogeneic stem cell transplant 1 week ago is transferred to the ICU for close monitoring with neutropenic fever and mild septic shock. He improves on antibiotics, has count recovery, and discussions begin about transferring back to the floor 5 days after ICU transfer. However, the oncologists are concerned about rising direct bilirubin (up to 8 mg/dL) associated with epigastric/RUQ pain and weight gain. RUQ ultrasound reveals hepatomegaly and ascites but does not show evidence of biliary obstruction.
Which of the following is the most likely diagnosis?A. Ascending cholangitis
Correct Answer: E
Hepatic sinusoidal obstruction syndrome (SOS, also known as venoocclusive disease) is an unusual complication of hematopoietic stem cell transplantation and involves injury to the liver venous endothelium likely from the conditioning chemotherapeutic regimen. Fibrin and factor 8 have been found in the vein walls and sinusoids, suggesting the existence of a pro-coagulant state. Risk factors include preexisting liver disease and certain chemotherapeutic agents. Most patients develop the syndrome within 3 weeks of transplant, and the clinical diagnosis is made by a combination of elevated direct bilirubin, hepatomegaly, and sudden weight gain. Important differentials to consider include Budd-Chiari, acute GVHD, viral hepatitis, and cholestatic drug reactions. Some evidence supports the use of prophylaxis with ursodiol or heparin. Management for severe disease includes the use of defibrotide, which increases plasmin activity and decreases vWF expression, though we await completion of the first phase 3 randomized controlled trial for this indication.