Inflammatory bowel disease (IBD) commonly refers to ulcerative colitis (UC) and Crohn's disease (CD), which are chronic inflammatory diseases of the GI tract of unknown etiology.
UC primarily involves the mucosa and the submucosa, with formation of crypt abscesses and mucosal ulceration. The mucosa typically appears granular and friable. In more severe cases, pseudopolyp formation occurs. This formation consists of areas of hyperplastic growth with swollen mucosa surrounded by inflamed mucosa with shallow ulcers. Although unusual, in severe UC, inflammation and necrosis can extend below the lamina propria to involve the submucosa and the circular and longitudinal muscles. UC arises first in the rectum, where it remains confined in about 25% of cases. In the remainder of cases, there is contiguous proximal spread. Pancolitis occurs in 10% of patients. The small intestine is never involved, except when the distal terminal ileum is inflamed in a superficial manner, referred to as backwash ileitis. Even with less than total colonic involvement, the disease is strikingly and uniformly continuous. As the disease becomes chronic, the colon becomes a rigid, foreshortened tube that lacks its usual haustral markings, leading to the "lead pipe" appearance seen on barium enema.
The quality of life generally is lower with CD than with UC, in part due to recurrences after surgery.
The most common causes of death in inflammatory bowel disease are peritonitis with sepsis, malignancy, thromboembolic disease, and complications of surgery. Toxic megacolon, one of the most dreaded complications of UC, can lead to perforation, sepsis, and death.
UC presents most commonly with bloody diarrhea. Abdominal pain and cramping, fever, and weight loss occur in more severe cases. The greater the extent of colon involved, the more likely the patient is to suffer from diarrhea. Rectal urgency or tenesmus reflects reduced compliance of the inflamed rectum. It is possible for patients to have formed stools if their disease is confined to the rectum. As the degree of inflammation increases, systemic symptoms develop. These symptoms may include low-grade fever, malaise, nausea, vomiting, sweats, toxicity and arthralgias. With severe UC, fever, dehydration, and abdominal tenderness develop, reflecting progressive inflammation into deeper layers of the colon.
IV cyclosporine is helpful in refractory UC. Hyperbaric oxygen therapy has been found helpful in the treatment of IBD that is unresponsive to other therapies. Loperamide (Imodium) and diphenoxylate are useful in mild disease to reduce the number of bowel movements and to relieve rectal urgency. The anticholinergic Bentyl may help relieve intestinal spasms. Antidiarrheal and anticholinergic medications must be avoided in acute severe disease because they may precipitate toxic megacolon. Patients with toxic megacolon initially require nasogastric suction and IV steroids. Failure to improve within 48 hours is an indication for total colectomy.