Colitis, Ulcerative

Ulcerative colitis (Colitis ulcerosa, UC) is a form of inflammatory bowel disease (IBD). Ulcerative colitis is a form of colitis, a disease of the intestine, specifically the large intestine or colon, that includes characteristic ulcers, or open sores, in the colon. The main symptom of active disease is usually constant diarrhea mixed with blood, of gradual onset. Ulcerative colitis is, however, believed to have a systemic etiology that leads to many symptoms outside the intestine. Because of the name, IBD is often confused with irritable bowel syndrome ("IBS"), a troublesome, but much less serious, condition. Ulcerative colitis has similarities to Crohn's disease, another form of IBD. Ulcerative colitis is an intermittent disease, with periods of exacerbated symptoms, and periods that are relatively symptom-free. Although the symptoms of ulcerative colitis can sometimes diminish on their own, the disease usually requires treatment to go into remission.

Ulcerative colitis occurs in 35–100 people for every 100,000 in the United States, or less than 0.1% of the population. The disease is more prevalent in northern countries of the world, as well as in northern areas of individual countries or other regions. Although ulcerative colitis has no known cause, there is a presumed genetic component to susceptibility. The disease may be triggered in a susceptible person by environmental factors. Although dietary modification may reduce the discomfort of a person with the disease, ulcerative colitis is not thought to be caused by dietary factors. Although ulcerative colitis is treated as though it were an autoimmune disease, there is no consensus that it is such. Treatment is with anti-inflammatory drugs, immunosuppression, and biological therapy targeting specific components of the immune response. Colectomy (partial or total removal of the large bowel through surgery) is occasionally necessary, and is considered to be a cure for the disease.

Causes

While the cause of ulcerative colitis is still unknown, several, possibly interrelated, causes have been suggested. Some think that the smallest illness could spark the disease.

Genetic factors

A genetic component to the etiology of ulcerative colitis can be hypothesized based on the following:

• Aggregation of ulcerative colitis in families.
• Identical twin concordance rate of 10% and dizygotic twin concordance rate of 3%
• Ethnic differences in incidence
• Genetic markers and linkages

There are 12 regions of the genome which may be linked to ulcerative colitis. This includes chromosomes 16, 12, 6, 14, 5, 19, 1, 16, and 3 in the order of their discovery. However, none of these loci has been consistently shown to be at fault, suggesting that the disorder arises from the combination of multiple genes. For example, chromosome band 1p36 is one such region thought to be linked to inflammatory bowel disease. Some of the putative regions encode transporter proteins such as OCTN1 and OCTN2. Other potential regions involve cell scaffolding proteins such as the MAGUK family. There are even HLA associations which may be at work. In fact, this linkage on chromosome 6 may be the most convincing and consistent of the genetic candidates.

Multiple autoimmune disorders have been recorded with the neurovisceral and cutaneous genetic porphyrias including ulcerative colitis, Crohn's disease, celiac disease, dermatitis herpetiformis, diabetes, systemic and discoid lupus, rheumatoid arthritis, ankylosing spondylitis, scleroderma, Sjogren's disease and scleritis. Physicians should be on high alert for porphyrias in families with autoimmune disorders and care must be taken with potential porphyrinogenic drugs, including sulfasalazine.

Environmental factors

Many hypotheses have been raised for environmental contributants to the pathogenesis of ulcerative colitis. They include the following:

• Diet: as the colon is exposed to many dietary substances which may encourage inflammation, dietary factors have been hypothesized to play a role in the pathogenesis of both ulcerative colitis and Crohn's disease. There have been few studies to investigate such an association, but one study showed no association of refined sugar on the prevalence of ulcerative colitis.
• Diet: A diet low in fermentable dietary fiber may affect ulcerative colitis incidence.
• Breastfeeding: There have been conflicting reports of the protection of breastfeeding in the development of inflammatory bowel disease. One Italian study showed a potential protective effect.

Several scientific studies have posted that Accutane is a possible trigger of Crohn's Disease and Ulcerative colitis in some individuals. Three cases in the United States have gone to trial thus far, with all three resulting in multi-million dollar judgements against the makers of isotretinoin. There are an additional 425 cases pending.

Autoimmune disease

Some sources list ulcerative colitis as an autoimmune disease, a disease in which the immune system malfunctions, attacking some part of the body. In contrast to Crohn's disease, which can affect areas of the gastrointestinal tract outside of the colon, ulcerative colitis usually involves the rectum and is confined to the colon, with occasional involvement of the ileum. This so-called "backwash ileitis" can occur in 10–20% of patients with pancolitis and is believed to be of little clinical significance. Ulcerative colitis can also be associated with comorbidities that produce symptoms in many areas of the body outside the digestive system. Surgical removal of the large intestine often cures the disease.

Alternative theories

Levels of sulfate-reducing bacteria tend to be higher in persons with ulcerative colitis. This could mean that there are higher levels of hydrogen sulfide in the intestine. An alternative theory suggests that the symptoms of the disease may be caused by toxic effects of the hydrogen sulfide on the cells lining the intestine. It may be caused by occlusions in the capillaries of the subepithelial linings, degenerated fibers beneath the mucosa and infiltration of the lamina propria with plasma cells

Course and complications

Progression or remission

Patients with ulcerative colitis usually have an intermittent course, with periods of disease inactivity alternating with "flares" of disease. Patients with proctitis or left-sided colitis usually have a more benign course: only 15% progress proximally with their disease, and up to 20% can have sustained remission in the absence of any therapy. Patients with more extensive disease are less likely to sustain remission, but the rate of remission is independent of the severity of disease.

Ulcerative colitis and colorectal cancer

There is a significantly increased risk of colorectal cancer in patients with ulcerative colitis after 10 years if involvement is beyond the splenic flexure. Those with only proctitis or rectosigmoiditis usually have no increased risk. It is recommended that patients have screening colonoscopies with random biopsies to look for dysplasia after eight years of disease activity.

Primary sclerosing cholangitis

Ulcerative colitis has a significant association with primary sclerosing cholangitis (PSC), a progressive inflammatory disorder of small and large bile ducts. As many as 5% of patients with ulcerative colitis may progress to develop primary sclerosing cholangitis.

Mortality

The effect of ulcerative colitis on mortality is unclear, but it is thought that the disease primarily affects quality of life, and not lifespan.

Treatment

Standard treatment for ulcerative colitis depends on extent of involvement and disease severity. The goal is to induce remission initially with medications, followed by the administration of maintenance medications to prevent a relapse of the disease. The concept of induction of remission and maintenance of remission is very important. The medications used to induce and maintain a remission somewhat overlap, but the treatments are different. Physicians first direct treatment to inducing a remission which involves relief of symptoms and mucosal healing of the lining of the colon and then longer term treatment to maintain the remission.

Drugs used:

• Aminosalicylates

Sulfasalazine has been a major agent in the therapy of mild to moderate UC for over 50 years. In 1977 Mastan S. Kalsi et al. determined that 5-aminosalicylic acid (5-ASA and mesalazine) was the therapeutically active compound in sulfasalazine. Since then many 5-ASA compounds have been developed with the aim of maintaining efficacy but reducing the common side effects associated with the sulfapyridine moiety in sulfasalazine.

• Mesalazine, also known as 5-aminosalicylic acid, mesalamine, or 5-ASA. Brand name formulations include Apriso, Asacol, Pentasa, Mezavant, Lialda, and Salofalk.
• Sulfasalazine, also known as Azulfidine.
• Balsalazide, also known as Colazal or Colazide (UK).
• Olsalazine, also known as Dipentum.

Corticosteroids

• Cortisone
• Prednisone
• Prednisolone
• Cortifoam
• Hydrocortisone
• Methylprednisolone
• Beclometasone
• Budesonide – under the brand name of Entocort

Immunosuppressive drugs

• Mercaptopurine, also known as 6-Mercaptopurine, 6-MP and Purinethol.
• Azathioprine, also known as Imuran, Azasan or Azamun, which metabolises to 6-MP.
• Methotrexate, which inhibits folic acid
• Tacrolimus

Biological treatment

• Infliximab
• Visilizumab
• Low Molecular Weight Heparin (LMWH) e.g. clexane is used in acute management of the flare of UC.

Surgery

Unlike Crohn's disease, ulcerative colitis can generally be cured by surgical removal of the large intestine. This procedure is necessary in the event of: exsanguinating hemorrhage, frank perforation or documented or strongly suspected carcinoma. Surgery is also indicated for patients with severe colitis or toxic megacolon. Patients with symptoms that are disabling and do not respond to drugs may wish to consider whether surgery would improve the quality of life.

Ulcerative colitis is a disease that affects many parts of the body outside the intestinal tract. In rare cases the extra-intestinal manifestations of the disease may require removal of the colon.

Alternative treatments

About 21% of inflammatory bowel disease patients use alternative treatments. A variety of dietary treatments show promise, but they require further research before they can be recommended.

In vitro research, animal evidence, and limited human study suggest that melatonin may be beneficial.

Smoking

Unlike Crohn's disease, ulcerative colitis has a lesser prevalence in smokers than non-smokers. Nonetheless, the risks of smoking contraindicate using cigarettes as a treatment for ulcerative colitis. Patients who choose to use smoking as a treatment should give serious consideration to the links between smoking cessation and the onset or relapse of ulcerative colitis.

Dietary modification

Dietary fibre, meaning indigestible plant matter, has been recommended for decades in the maintenance of bowel function. Of peculiar note is fibre from brassica, which seems to contain soluble constituents capable of reversing ulcers along the entire human digestive tract before it is cooked. Oatmeal is also commonly prescribed.

Fats and oils

• Fish oil. Eicosapentaenoic acid (EPA), derived from fish oil. This is an Eicosanoid that inhibits leukotriene activity, the latter which may be a key factor of inflammation. As an IBD therapy, there are no conclusive studies in support and no recommended dosage. But dosages of EPA between 180 to 1500 mg/day are recommended for other conditions, most commonly cardiac.
• Short chain fatty acid (butyrate) enema. The colon utilizes butyrate from the contents of the intestine as an energy source. The amount of butyrate available decreases toward the rectum. Inadequate butyrate levels in the lower intestine have been suggested as a contributing factor for the disease. This might be addressed through butyrate enemas. The results however are not conclusive.

Herbals

Herbal medications are used by patients with ulcerative colitis. Compounds that contain sulphydryl may have an effect in ulcerative colitis (under a similar hypothesis that the sulpha moiety of sulfasalazine may have activity in addition to the active 5-ASA component). One randomized control trial evaluated the over-the-counter medication methionine-methyl sulphonium chloride (abbreviated MMSC, but more commonly referred to as Vitamin U) and found a significant decreased rate of relapse when the medication was used in conjunction with oral sulfasalazine.

Bacterial recolonization

• Probiotics may have benefit. One study which looked at a probiotic known as VSL#3 has shown promise for people with ulcerative colitis.
• Fecal bacteriotherapy involves the infusion of human probiotics through fecal enemas. It suggests that the cause of ulcerative colitis may be a previous infection by a still unknown pathogen. This initial infection resolves itself naturally, but somehow causes an imbalance in the colonic bacterial flora, leading to a cycle of inflammation which can be broken by "recolonizing" the colon with bacteria from a healthy bowel. There have been several reported cases of patients who have remained in remission for up to 13 years.

Intestinal parasites

Inflammatory bowel disease is less common in the developing world. Some have suggested that this may be because intestinal parasites are more common in underdeveloped countries. Some parasites are able to reduce the immune response of the intestine, an adaptation that helps the parasite colonize the intestine. The decrease in immune response could reduce or eliminate the inflammatory bowel disease.

Helminthic therapy using the whipworm Trichuris suis has been shown in a randomized control trial from Iowa to show benefit in patients with ulcerative colitis. The therapy tests the hygiene hypothesis which argues that the absence of helminths in the colons of patients in the developed world may lead to inflammation. Both helminthic therapy and fecal bacteriotherapy induce a characteristic Th2 white cell response in the diseased areas, which is somewhat paradoxical given that ulcerative colitis immunology was thought to classically involve Th2 overproduction.