INTRODUCTION: Pyogenic liver abscess (PLA) and superior mesenteric vein (SMV) thrombosis are infrequent complications of Crohn's disease (CD). A combination of the two is even rarer. Our review of literature revealed only two other such cases. This case not only demonstrates a concurrent presence of two rare manifestations of Crohn's disease, but also the challenges associated with management. CASE DESCRIPTION: We present the case of a 30 year old male diagnosed with Crohn's disease 8 years ago managed with Azathioprine therapy. He initially presented with severe left lower quadrant abdominal pain for 4 weeks. CT scan of the abdomen revealed segmental thickening in the small bowel wall, indicating a flare up. He was prescribed a course of oral prednisone for four weeks. His pain initially improved, but recurred two weeks later, now in the right upper quadrant and epigastrium along with nausea, vomiting and diarrhea. Upon presentation, he was febrile at 38.4 celsius. Laboratory workup showed a WBC count of 13.4, ESR 69, CRP 23.2, AST 45, ALT 34, total bilirubin 1.1, lipase 84. A repeat CT scan now showed new SMV thrombosis and a 5.4 x 4.1cm abscess in the right hepatic lobe. Steroids were discontinued and the patient was treated with IV fluids, heparin drip, piperacillin-tazobactam and percutaneous hepatic drain placement. The purulent fluid grew Streptococcus intermedius and Staphylococcus aureus on culture. A colonoscopy was also done showing severe active ileitis and colitis. At this point, the decision was made to commence immunosuppressive therapy with Adalimumab, as the flare up needed to be addressed. The patient was switched to oral Augmentin for a total 4 weeks of antibiotics and was discharged on Rivaroxaban for 6 months, after his clinical status improved.Figure: CT scan of abdomen with IV contrast with an abscess in the right hepatic lobe measuring 5.4 x 4.1cm.Figure: CT of the abdomen demonstrating complete occlusion of the superior mesenteric vein by a thrombosis.DISCUSSION: PLA and SMV thrombosis are uncommon manifestations of CD. SMV thrombosis has been reported as low as 1.3% and 1.7% of CD patients whereas PLA has been seen in 5.45 per 10,000 person years. This case poses a dilemma on how a patient with PLA in the setting of an acute CD flare up should be treated. It also brings to light the lack of adequate evidence on choice and duration of anticoagulation therapy for splanchnic vein thromboses, as the current guidelines rely mainly on expert opinion. The current standard of care is warfarin for 6 months with a target INR of 2.0 - 3.0. Novel oral anticoagulants have not been studied sufficiently and are prescribed on a case to case basis.