Small Bowel Obstruction: A Novel Complication of Superior Mesenteric Vein Thrombosis

Abstract

Introduction: Superior mesenteric vein thrombosis (SMVT) is rare condition, and it accounts for 1 in 5,000 inpatient admissions for abdominal pain. It is usually an incidental finding or a diagnosis found during work-up of abdominal pain. Intestinal infarction is one of its well-recognized complications. Here, we report an unusual case of small bowel obstruction (SBO) secondary to SMVT. A 71-year-old woman with a history of colon cancer (had chemotherapy and transverse hemicolectomy 5 years ago) presented with complains of persistent vomiting for the past 2 days and abdominal pain for 1 day. Her vital signs were temperature 98° F, pulse 90 beats/minute, blood pressure 120/70 mm Hg. Physical examination was remarkable for distended abdomen with no rigidity or guarding. Laboratory work showed metabolic acidosis with lactic acid 5.77 mg/dL, hemoconcentration (hematocrit 46%). CT abdomen with contrast showed SBO due to an ill-defined mass at the ileo-transverse colonic anastomosis, which was contiguous with the mural thickening. It also showed bowel wall edema, SMVT (Figure 1) and superior mesenteric artery (SMA) narrowing. Surgical intervention was planned, but was not done, as the patient preferred conservative management. She responded well to hydration and nasogastric suction with resolution of lactic acidosis. She tolerated regular diet before discharge. During her third admission within a month with similar presentation, CT scan abdomen was repeated, which showed interval resolution of ileo-transverse colonic mass as seen on previous imaging, unchanged bowel edema, SMVT, and narrowing of SMA. Small bowel follow-through confirmed absence of luminal obstruction along with non-uniform caliber of the small bowel consistent with SMVT. She was diagnosed as a case of SMVT presenting as SBO. She was managed with therapeutic anticoagulation and a clear liquid diet, which was later transitioned to regular diet. To the best of our knowledge, this is the first case of SMVT presenting as SBO. A high index of suspicion is required to diagnose SMVT as a cause of SBO since early initiation of therapeutic anticoagulation forms the essential component of management.Figure 1: SMVT (arrow).