An Unusual Case of Hemorrhagic Enteritis

Abstract

A 59-year-old man presented with acute diffuse abdominal pain 2 months post a mechanical mitral valve replacement complicated by atrial fibrillation requiring warfarin. He had no melena or hematochezia. There was severe generalized abdominal tenderness. CBC and lactic acid level were normal. INR was 2.1 and aPTT was 116 s. CT of the abdomen showed segmental wall thickening with surrounding inflammation involving the small bowel. Warfarin was held, and conservative management was initiated. However, the pain worsened, and he developed abdominal distention, anemia and lactic acidosis. CT angiography demonstrated worsening small bowel wall thickening and hemoperitoneum. Mesenteric vessels were patent. Due to suspected intestinal infarction, urgent exploratory laparotomy was done. Severely inflamed segments of the small bowel with significant induration and hyperemia, and significant intraperitoneal hemorrhage were visualized. Intraoperative Doppler studies of the affected segments showed adequate flow. Findings were consistent with a hemorrhagic enteritis. Supportive care was continued. His symptoms subsided, and he was discharged home on warfarin.2554_A Figure 1. Macroscopic picture of the small bowel during exploratory laparotomy showing multiple segments in the small bowel appearing severely inflamed, with significant induration and hyperemia, and significant intraperitoneal bleeding (not seen in this picture).2554_B Figure 2. Endoscopic picture of the terminal ileum showing nodular erythematous mucosa.2554_C Figure 3. Endoscopic picture of the duodenum showing diffuse hemorrhagic mucosa without active bleeding.Over the next 5 months he was readmitted 3 additional times for similar symptoms and imaging findings. Therapeutic INR, and markedly prolonged aPTT up to 170 s, were re-demonstrated. Colonoscopy was done and showed edematous hyperemic nodular terminal ileum. Focal active ileitis was seen on pathology. EGD showed diffuse hemorrhagic duodenal mucosa without active bleeding. Hemorrhage in the lamina propria was seen on pathology. Extensive workup for inflammatory and infectious causes of hemorrhagic enteritis was negative. Ultimately, extensive hematologic workup identified a deficiency in the intrinsic coagulation pathway consistent with factor IX propeptide mutation causing warfarin hypersensitivity. Therefore, a bioprosthetic valve replacement was performed and warfarin discontinued. Since the surgery and up to this date, he has not experienced any recurrent symptoms. In contrast to genetic polymorphism affecting warfarin metabolism, hypersensitivity to warfarin due to factor IX propeptide mutations, is a rare phenomenon that causes marked prolongation of aPTT by decreasing factor IX levels. It can lead to life-threatening hemorrhage despite INR being therapeutic. We report this case to raise awareness of this disorder that requires early recognition to avoid life-threatening hemorrhage with warfarin use.