The transverse colon is short in the dog (on the order of 5 to 8 cm) and is delimited proximally by the hepatic flexure. The transverse colon is entered by directing the end of the endoscope dorsally at the splenic flexure. Once the colon has been adequately distended, the endoscope is advanced into the descending colon up to the splenic flexure (i.e., the junction between the descending and transverse colon). Occlusion of the anal orifice improves insufflation by preventing air leakage. After a digital rectal examination has been performed, the endoscope is lubricated with a local anesthetic gel and the endoscope is advanced into the rectum using moderate insufflation to lift the rectal mucosa off of the endoscope. In the dog and cat, there is no sigmoid flexure and the colon is fairly easily intubated. In Canine and Feline Gastroenterology, 2013 Endoscopic TechniqueĮndoscopy of the colon is performed with the animal placed in left lateral recumbency to avoid the accumulation of fluid in the transverse colon and to facilitate passage of the colonoscope at the splenic flexure. The authors quoted seven other published cases of pseudoephedrine-related ischemic colitis, all occurring at much lower dosages, at most 240 mg/day. She made a good recovery and was said to have stopped taking pseudoephedrine. Before each of her two admissions she had been taking a remarkably high dose of 900 mg/day, and on many other occasions had taken as much as 600 mg/day. In fact she had often noticed abdominal pain and distension, with occasional bloody diarrhea, after taking pseudoephedrine. It emerged that she had been taking pseudoephedrine for 2 years, because she found that it relieved her headaches. On this as on the previous occasion, emergency laparotomy was needed and she was found to have patchy infarction of the terminal ileum and the ascending colon. Ī 51-year-old woman presented for the second time in 4 months with abdominal pain.His mesenteric vasculature was normal on subsequent magnetic resonance angiography and no other abnormalities were found, leading to the presumption that the drug had caused mesenteric vasoconstriction. Ī 33-year-old man took pseudoephedrine 240 mg/day for 5 days.In all cases there was ischemic colitis affecting predominantly the splenic flexure, and there was full recovery after drug withdrawal. Three of them had taken the drug for about 1 week, the fourth for 6 months. Perimenopausal women may be more susceptible, and a group from Yale have described four patients, women aged 35–50 years, who developed ischemic colitis while taking pseudoephedrine. However, in tall thin people, the transverse colon may extend into the pelvis.The vasoconstrictor action of pseudoephedrine can predispose susceptible patients to ischemic colitis, particularly in the watershed area of the splenic flexure. Being freely movable, the transverse colon is variable in position, usually hanging to the level of the umbilicus (L 3 vertebral level). The root of the transverse mesocolon lies along the inferior border of the pancreas and is continuous with the parietal peritoneum posteriorly. The mesentery is adherent to or fused with the posterior wall of the omental bursa. The transverse colon and its mesentery, the transverse mesocolon, loops down, often inferior to the level of the iliac crests. It lies anterior to the inferior part of the left kidney and attaches to the diaphragm through the phrenicocolic ligament. The left colic flexure (splenic flexure) is usually more superior, more acute, and less mobile than the right colic flexure. It crosses the abdomen from the right colic flexure to the left colic flexure, where it turns inferiorly to become the descending colon. The transverse colon is the third, longest, and most mobile part of the large intestine.
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