The ischemic process is transient and limited to the mucosa, with fibrosis and formation of colonic strictures in the late phase. 10 Ischemic colitis is caused by hypoxemia to the terminal vascular distribution of the intestines. 9 Hemodialysis tends to cause repeated hypotensive episodes and may thus induce induce vasoconstriction of the vasa recta in the right colon, leading to colonic ischemia. The right colon is predominantly involved in the hemodialysis population. In the case documented above, cat scratch colon was seen in a patient with ischemic colitis. This lack of compliance may aggravate superficial mucosal injury from excessive insufflation during colonoscopy. The deposition of subepithelial collagen makes the bowel wall stiff and non-distensible. 1, 2 Variable amounts of chronic inflammatory infiltration is typically present in the lamina propria, with an increased number of intraepithelial lymphocytes.
Recently, significant hemorrhagic linear marks have been reported to occur during colonoscopy in patients with collagenous colitis. However, barotrauma alone is not the sole cause of cat scratch colon. 8 This supports the hypothesis that cat scratch colon is commonly associated with barotrauma etiology. Recently, colonic perforation due to high air pressure was reported following observation of a cat scratch colon. Until recently, the main proposed causative mechanism has been barotrauma due to excess insufflation of air. Although the cause is unclear, there are several hypotheses: Barotrauma from air insufflation into a less compliant colon during colonoscopy, 1 complications resulting from collagenous colitis, 2, 3 tension in the wall of a cylindrical vessel, 5 lesions related to diversion colitis, 4 chronic cholestasis and its complications, 6 chronic anti-inflammatory drug ingestion, 7 and others. 1 Cat scratch colon is defined as the presence of linear mucosal breaks in the cecum and ascending colon the scratches are of variable length, bright red, resembling a cat scratch. These lesions have a prevalence rate of 0.25%. Over the past few years, very few cases have been reported. "Cat scratch colon" was described for the first time in 2007. The patient no longer complained of abdominal pain or hematochezia. On CT scans, improvement in ischemic colitis was noted. No further mucosal tearing was observed during the follow-up colonoscopy. On follow-up colonoscopy, the previous severe ischemic colonoscopic findings had disappeared, and ischemic mucosal change showed further resolution ( Fig. After 3 weeks, follow-up colonoscopy and CT were performed. The patient was placed on bowel rest until the symptoms resolved. Intravenous fluids were administered to treat dehydration, and total parenteral nutrition with prophylactic antibiotics was provided. The patient thus received supportive care. The patient was diagnosed with ischemic colitis based on colonoscopic and CT findings, and clinical manifestations. Computed tomography (CT) scan showed moderate-to-severe diffuse bowel wall thickening and focally decreased mucosal enhancement in the right colon. The remaining colorectal mucosa was grossly normal. Cecal intubation was not performed because of severe ischemic changes with necrosis. In the ascending colon, dark purple edematous mucosa and necrotic epithelial lesions were found ( Fig. Upon examination of the distal transverse colon, we found several deep linear red mucosal breaks resembling scratches ( Fig. The colonoscopic findings showed diffuse bowel wall edema. Colonoscopy was performed after standard bowel preparation and under sedation with 3 mg of midazolam. An esophagogastroduodenoscopy revealed no evidence of bleeding. The electrocardiogram showed normal results. On stool examination, negative results were obtained for stool WBC, stool culture, and Clostridium difficile toxin A/B. Anemia was associated with chronic renal failure. Serum was negative for antinuclear antibody and HIV antibody. Serum biochemistry showed creatinine level, 6.6 mg/dL albumin level, 3.0 g/dL alanine aminotransferase level, 36 IU/L aspartate aminotransferase level, 38 IU/L bilirubin level, 1.2 mg/dL and alkaline phosphatase level, 198 IU/L with normal electrolytes. Laboratory tests revealed a white blood cell (WBC) count of 13,900/mm 2, a hemoglobin level of 9.4 g/dL, and a platelet count of 228,000/mm 2. On physical examination, she was found to have right abdominal pain and tenderness. The patient's hemodynamic parameters were stable. She underwent hemodialysis three times per week. She had a history of end-stage renal disease, hypertension, and diabetes mellitus. A 65-year-old woman was referred for colonoscopy because of abdominal pain and hematochezia.
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