This is a case of toxic dilatation of the colon in a patient who is thought to have Crohn's disease. Notice the featureless distended colon, particularly at the splenic flexure and the irregular mucosal pattern near the hepatic flexure.
Initial treatment is with broad spectrum antibiotics and intravenous steroids. If the patient fails to respond, then total colectomy with ileostomy would be the preferred emergency treatment.