Abstract Introduction Sinusoidal obstruction syndrome (SOS), previously known as veno-occlusive disease, is an uncommon complication following hematopoietic stem cell transplantation (HSCT) that causes damage to sinusoidal endothelium. Resultant sinusoidal sloughing occludes hepatic venous vasculature and can ultimately cause liver injury. Increasing awareness of SOS is crucial to early identification and treatment. Case Report A 23-year-old man with Sweet syndrome and high-risk myelodysplastic syndrome presented with fevers, lower extremity rash, and dizziness. He was initially admitted for sepsis workup and hematology evaluation. Symptoms were ultimately determined to be a Sweet syndrome flare. During admission, the patient opted to pursue HSCT. He underwent busulfan/cyclophosphamide conditioning before HSCT and received post-transplant cyclophosphamide. Tacrolimus and mycophenolate were chosen for chronic immunosuppression, and he was placed on ursodiol for SOS prophylaxis. On day 23 post-HSCT, he was found to have increasing liver dysfunction in a cholestatic pattern. Abdominal ultrasound revealed newly increased hepatic echogenicity, small volume perihepatic ascites, and flow reversal in the central portal vein. Review of his weight also showed a 10% increase from the previous nadir. Notable lab studies were an AST 153, ALT 29, ALP 499, total bilirubin 2.29, and INR 1.87. SOS was determined as the likely cause of his liver injury, and he was started on defibrotide treatment on day 27 post-HSCT. The patient worsened and developed multi-organ failure, shock, and generalized mucosal bleeding over the following days. Defibrotide was held three days after its initiation due to bleeding complications. Despite aggressive treatment with multiple vasopressors, renal replacement therapy, broad infectious coverage, and transfusional support, his liver function and overall clinical condition failed to improve. After extensive goals-of-care discussions with his family, they opted for a do-not-resuscitate status, and the patient unfortunately died later that day. Discussion Left untreated, SOS can rapidly cause liver dysfunction even in those without previous liver disease. Defibrotide is the only treatment available for SOS and is thought to improve fibrinolysis and protect endothelium from inflammation; however, caution is warranted due to the possibility of bleeding complications. Previous studies with defibrotide found relatively low rates of adverse events but estimated that a tenth of patients experience severe bleeding events. In addition, defibrotide may need to be shipped from other facilities due to its limited use, which could delay treatment. Given the potentially fatal consequences of a late diagnosis, this case highlights the importance of early recognition and treatment of SOS. This abstract is funded by: None
Nguyen et al. (Fri,) studied this question.