A 62-year-old man visited the emergency room complaining of epigastric and periumbilical pain, which had developed 3 hours prior to his admission. The nature of his complaint was colicky pain, but he had experienced neither nausea nor vomiting. He had no history of abdominal surgery, allergic disease, or food sensitivity. Physical examination revealed right lower quadrant abdominal tenderness, but no rebound tenderness. The patient's leukocyte count was 10,420/mm
3 (2.9% eosinophils, normal range [NR], 0~5%). Abdominal computed tomography (CT) examination showed segmental wall thickening of the small bowel and proximal dilatation, mesenteric edema, and focal fluid collection in the adjacent peritoneal cavity (
Figure 1). However, there was no abrupt transition in the luminal diameter at either end of the pathologic bowel loop, suggesting a radiological abnormality, other than the strangulation normally observed in a case of intestinal obstruction. The radiological differential diagnosis included segmental enteritis of unclear cause, and focal mesenteric ischemia by a certain kind of systemic vasculitis, or post- strangulation state following the relief of obstruction. Twelve hours after his admission to the emergency room, the abdominal pain progressed, rebound tenderness developed, and finally, an exploratory laparotomy was performed. Exploration revealed edema, congestion, and bluish discoloration of the distal ileum, 50 cm from the ileocecal valve. Only a 15 cm segment was involved, and the remaining bowel was seen to be normal. The proximal bowel was dilated and the distal bowel had collapsed. The involved ileal segment was resected, and end-to-end anastomosis was performed. Gross examination showed an ill-defined mass-like wall thickening with multifocal erosion of the overlying mucosa, 7 centimeters in length, and the surrounding small intestinal mucosa was moderately edematous. Histologically, extensive eosinophilic infiltration was found in the mass-like lesion, which was found from submucosa to subserosa (
Figure 2). In the surrounding mucosa, edema with increased eosinophils was also observed. There was found to be no evidence of parasites, granulomas, malignancy, vasculitis, or embolism in the surgical specimen, either in the bowel wall or in the mesenteric vessels. The final diagnosis was eosinophilic enteritis. Two days after the operation, the patient's leukocyte count decreased to 8,070/mm
3 (8.7% eosinophils). The pain disappeared and he was discharged normally. At the outpatient clinic, 12 days after the operation, the patient's total IgE was 1,310 u/mL above the normal range (0~100 u/mL), but skin prick test was normal, suggesting no specific allergic etiology. Seventeen days after the operation, similar characteristic abdominal pain developed again in the patient's periumbilical area, but to a milder degree than before the operation. The patient was advised to undergo gastroenterological testing in order to evaluate the abdominal pain, but he refused. Instead he (60 kg-weight) received 40 mg intramuscular injections of methylprednisolone acetate for two days, and simultaneously took 10 mg prednisolone three times per day, resulting in improvement of abdominal pain. Two weeks after this abdominal pain attack, hematochezia occurred for 4 days, in spite of continuous 30 mg prednisolone per day. The patient experienced dizziness, and his hemoglobin decreased from 13.6 g/dL (NR, 13-17 g/dL) to 9.5 g/dL. He was readmitted for a diagnostic work-up. Emergency colonoscopy showed no evidence of bleeding after bowel preparation with colyte, nor did it reveal any definite mucosal abnormality up to the ileocecal valve. Although there was no definite intrinsic mucosal lesion, six pieces of blind biopsy were taken from the hepatic flexure and 40 cm above the anal verge, but the pathologic results indicated only nonspecific change. In addition, gastroduodenoscopy up to the 3
rd portion of duodenum revealed no abnormalities, and there was no evidence of bleeding. On the next day, the initial negative
99mTc-tagged red blood cell scan showed a small amount of bleeding from the right iliac artery 2 hours and 30 minutes after injection of
99mTc-tagged red blood cells, and migration of blood into the right ileal lumen after 4 hours and 30 minutes. However, CT angiography and arteriography, which were taken successively, showed no focus of bleeding, indicating that the bleeding had already stopped, or that the bleeding speed was slower than 0.5 mL/min. On the next day, M2A™ capsule endoscopy was performed. It showed that multiple hemorrhagic spots were scattered throughout the proximal jejunum (
Figure 3A). After the normal jejunal segment, abrupt spurting of fresh arterial bleeding was detected in the mid-to-distal jejunum, but no ulcer, mass or vascular abnormalities were detected (
Figure 3B). The ileum was normal, and the anastomotic site at the ileum was not noticed, suggesting no definite lesion around the previous operation site. Just 8 hours after the capsule endoscopy examination, a large amount of hematochezia, dizziness, and diaphoresis occurred, along with a decrease in hemoglobin level, from 9.7 g/dL to 6.9 g/dL. The patient did not take oral prednisolone during the 2 days of examination due to the unavailability of an oral intake state. Immediately after the detection of massive hematochezia, intravascular injections of 125 mg methylprednisolone sodium succinate per every 8 hours were started, and an emergency operation was prepared. Surprisingly, the hemoglobin increased to 10.7 g/dL with 3 packs of RBC transfusion, suggesting termination of the bleeding. Thereafter, the patient's hematochezia was undetected, and his hemoglobin remained stable. Five days later, the methylprednisolone sodium succinate injections were replaced with oral prednisolone treatment, 60 mg per day for 2 days, which was to taper down over a two-week period. The patient has been asymptomatic for 15 months with no medical therapy.