<unk>  must be differentiated from the many other causes of abdominal pain and rectal bleeding (for example, infection, inflammatory bowel disease, diverticulosis, or colon cancer). It is also important to differentiate<unk> , which often resolves on its own, from the more immediately life-threatening condition of acute mesenteric<unk>  of the small bowel. There are devices which test the sufficiency of oxygen delivery to the colon. The first device approved by the U.S. FDA in 2004 uses visible light spectroscopy to analyze capillary oxygen levels. Use during Aortic Aneurysm repair detected when colon oxygen levels fell below sustainable levels, allowing real-time repair. In several studies, Specificity has been 90% or higher for acute colonic<unk> , and 83% for chronic mesenteric<unk> , with a sensitivity of 71%-92%. This device must be placed using endoscopy, however. Diagnostic tests There is a recent optical test, but it requires endoscopy (see Diagnosis). There are no specific blood tests for<unk> . The sensitivity of tests among 73 patients were: * The white blood cell count was more than 15,000/mm3 in 20 patients (27%) * The serum bicarbonate level was less than 24 mmol/L in 26 patients (36%) Plain X-rays are often normal or show non-specific findings. In a series of 73 patients, plain abdominal radiography (56%) showing colic distension in 53% or a pneumoperitoneum in 3%. CT scans are often used in the evaluation of abdominal pain and rectal bleeding, and may suggest the diagnosis of<unk> , pick up complications, or suggest an alternate diagnosis. Endoscopic evaluation, via colonoscopy or flexible sigmoidoscopy, is the procedure of choice if the diagnosis remains unclear.<unk>  has a distinctive endoscopic appearance; endoscopy can also facilitate alternate diagnoses such as infection or inflammatory bowel disease. Biopsies can be taken via endoscopy to provide more information. Visible light spectroscopy, performed using catheters placed through the 5 mm channel of the endoscope, is diagnostic (see Diagnosis).
Ischemic colitis
Ulcerative colitis
Diversion colitis
Chemical colitis
Collagenous colitis
Cytomegalovirus colitis
Microscopic colitis
Diverticulitis