An inflammatory bowel disease (IBD) that causes long-lasting inflammation and ulcers in the digestive tract. The innermost lining of the large intestine and rectum are affected. The two main entities of IBD are ulcerative colitis (UC) and Crohn’s disease (CD). IBD shows alternating bouts of remission and flares of active inflammation. UD affects mostly the superficial mucosal layer of the gut wall in a continuous fashion extending proximally from the anus to variable degrees. In contrast, CD typically involves all layers of the gut wall and is discontinuous and patchy.
Doctors classify UC based on the location:
- Ulcerative proctitis, confined to the area closest to the anus, tends to be the mildest
- Proctosigmoiditis involves the rectum and sigmoid colon, which is the lower end of the colon.
- Left-sided colitis extends from the rectum up through the sigmoid and descending colon
- Pancolitis often affects the entire colon.
- Acute severe ulcerative colitis is a rare form that affects the entire colon
Symptoms of ulcerative colitus usually develop over time rather then suddenly. Symptoms can vary and may include diarrhea, often with blood or pus, abdominal pain and cramping, rectal pain, rectal bleeding, urgency to defecate, inability to defecate despite urgency, weight loss, fatigue, fever and in children, failure to grow.
Complications include severe bleeding, perforated colon, severe dehydration, liver disease (rare), osteoporosis, inflammation in skin, joints and eyes, increased risk of colon cancer, rapidly swelling colon (toxic megacolon) and increased risk of blood clots in veins and arteries.
The exact cause of ulcerative colitis is not known but diet and stress are known factors that aggravate the disease. One possible cause is immune system malfunction where an abnormal immune response to viruses or bacterium causes the it to attack the cells in the digestive tract. Heredity appears to play a role as well.
Ulcerative colitis is often diagnosed after ruling out other possible causes for symptoms. Diagnosis may be confirmed with the following tests:
- Blood, tested for anemia
- Stool sample, where white blood cells can indicate ulcerative colitis and absence of infection can rule out other causes for the symptoms.
- Colonoscopy allows the doctor to see inside the colon and possibly take a tissue biopsy. Flexible sigmoidoscopy is a procedure where a slender, flexible, lighted tube used to examine the rectum and sigmoid, the last portion of the colon.
- X-ray can be used for severe symptoms to rule out serious complications such as a perforated colon.
- CT scan of the abdomen or pelvis can be used to look for complications of the disease or assess the inflammation.
- Computerized tomography (CT) enterography and magnetic resonance (MR) enterography are noninvasive tests used to exclude inflammation in the small intestine. These tests are more sensitive for finding inflammation in the bowel than conventional imaging tests. MR enterography is a radiation-free alternative.
Pharmacological treatments are used for acute, active disease and to maintain response and precent relapse in patients in remission. For mild to moderate UC cases treatment includes aminosalicylates, steroids and immunosuppressants. Aminosalicylates are a family of medications, where the active ingredient is mesalamine. Aminosalicylates are thought to reduce inflammation of the intestines. Corticosteroids are short term therapies used to lower the activity of the immune system and limit inflammation in the intestines.
Surgery will be required in 16% of people suffering from UC. Surgery may involve removal of the large intestine and rectum (colectomy) in severe case of UC. An ileostomy, connection of the small bowel to the exterior of the body, and a bag or ostomy appliance is attached to the abdomen to collect feces. Surgeons may in some cases convert an ileostomy to an ileal pouch anal anastomosis (IPAA), also referred to as a pelvic pouch. The IPAA pouch is inside the body and stool is expelled through the anus rather than an ostomy bag.
Some strains of bacteria cause intestinal ulceration and chronic inflammatory bowel diseases. Intestinal microbiota have an important role in maintaining innate immunity, the nonspecific defense mechanisms that occur immediately or within hours or an antigen appearance in the body. In addition to fecal microbiota transplant (FMT), probiotics are also increasingly being used to treat UC and both are under investigation. Probiotics are living non-pathogenic bacteria such as Lactobacillus, Bifidobacterium, and Enterococcus.
FMT can reduce bowel permeability and thus the severity of the disease by increasing production of short-chain fatty acids, such as butyrate, which help maintain epithelial barrier integrity. FMT can restore immune dysbiosis by inhibiting differentiation of Th1 cells, T cell activity, leukocyte adhesion and production of inflammatory factors. FMT has been shown to have value in treating UC by changing the abundance of bacterial flora and improving the scores for diarrhea, abdominal pain and mucous membrane lesions.
Systematic Review with Network Meta-Analysis: Comparative Efficacy of Biologics in the Treatment of Moderately to Severely Active Ulcerative Colitis
Adrian D. Vickers, Claire Ainsworth, Reema Mody, Annika Bergman, Caroline S. Ling, Jasmina Medjedovic, Michael Smyth
October 24, 2016
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