Inflammatory Bowel Disease

Inflammatory Bowel Disease Michael Wong, MD

Definition Inflammatory bowel disease consists of ulcerative colitis and Crohn's disease. Ulcerative colitis is an idiopathic disorder characterized by inflammation limited to the mucosal layer of the colon, almost invariably involving the rectum and extending in a proximal and continuous fashion to involve other portions of the colon. Crohn's disease is characterized by transmural rather than superficial inflammation involving the entire bowel wall from mucosa to serosa. This transmural inflammatory process gives rise to fibrosis and the obstructive clinical presentations which are common and not seen often in ulcerative colitis. In addition, as part of the transmural inflammatory process, sinus tracts burrow through and penetrate the serosa, giving rise to microperforations and fistula, which are also part of the clinical picture of Crohn's disease. Unlike ulcerative colitis, which is limited to the colon, Crohn's disease may involve the entire gastrointestinal tract from mouth to perianal area. About 80% of patients have small bowel involvement, usually in the distal ileum, with one third of patients having ileitis alone. Approximately 50% of patients will have both ileal and colonic involvement, so-called ileocolitis; and 20% will have disease limited to the colon. In those cases, about 50% of patients with Crohn's colitis will have sparing of the rectum. A small percentage of patients will have predominance of involvement in the mouth or gastroduodenal area. Lesser numbers will have involvement of the esophagus and proximal small bowel. Epidemiologic, Etiologic and Pathophysiologic Features Although both diseases have a worldwide distribution, the incidence is highest in developed areas including North America, northern Europe and, to a lesser extent, South Africa and Australia. They tend to occur in northern areas of a given country. These disorders tend to be diseases of younger people, with peak incidence occurring in the late teens and early 20s up to age 40. Nonetheless, it should be recognized that both ulcerative colitis and Crohn's disease may occur for the first time in older patients, and several studies have suggested a second peak of incidence for both disorders in patients over the age of 60. In the older age group, it can be especially difficult to distinguished inflammatory bowel disease from ischemic disease. The patients and greater in Caucasians than blacks. But as with the geographic distributions these conditions spare no ethnic, racial or socioeconomic group. There is a clear familial pattern of inflammatory bowel disease, in that 10 to 25% of patients who develop either ulcerative colitis or Crohn's disease will have a close relative who also has a form of inflammatory bowel disease; and there tends to be a strong concordance for disease category, especially with regard to Crohn's disease. For Crohn's disease there is evidence for concordance for age of onset, disease location and severity of the clinical course. Despite the obvious genetic predisposition, the majority of patients will not have a close relative with IBD, and the influence of genetic predisposition versus environmental factors remains unclear.

Both of these disorders are idiopathic, with the etiology being unknown. As suggested above, there is considerable research interest in identifying a specific gene or genes which might be at the root, at least in a subgroup of patients. It is clear that perturbations of the immune system are occurring, and whether these are at the primary basis for etiology or represent a response to an inciting factor is not completely clear. Much attention for many years has focused on an infectious etiology. Most of the recent interest has centered on an atypical mycobacterium which has been isolated from the tissues of certain patients with Crohn's disease and for which there is variable histopathologic evidence associating this tuberculosis-like organism with Crohn's disease. There is recent data linking prior measles infection to an increased risk of developing Crohn's disease and the possible induction of a small-vessel granulomatous vasculitis. From the distribution of the disorders, it would appear as though environmental factors are important. One such factor which has been uncovered is the relation of cigarette smoking to IBD. With regard to Crohn's disease, smoking seems to exacerbate and may predispose to the disorder. On the other hand, with regard to ulcerative colitis, cigarette smoking appears to be protective, and one of the highest groups at risk for the development of ulcerative colitis are those individuals who have recently stopped smoking. With regard to the pathophysiology of inflammatory bowel disease, there is a large amount of research focused in this area, but as yet no unifying hypothesis has been developed. Current thinking suggest that there is disruption of the mucosal barrier, perhaps by a variety of external influences including infectious agents, anti-inflammatory drugs and possibly certain reactions with food. This disruption of the mucosal barrier along with possible genetically determined increased gut permeability allows antigens related to food and to bacterial metabolic products to enter the submucosa where there may be abnormal processing of these antigens leading to stimulation of helper T-cells instead of the normal mechanism of stimulation of suppressor T-cells which leads to physiologic tolerance. When this process goes awry and there is a stimulation of helper T-cells as well as macrophages, a variety of inflammatory mediators including cytokines and tumor necrosis factor are released causing an inflammatory process which then becomes chronic, leading to the observed pathologic and clinical abnormalities seen in both ulcerative colitis and Crohn's disease. This abnormal processing of antigens and the susceptibility of disruption of the mucosal barrier may be under genetic influence. Ulcerative Colitis - Clinical Features Rectal bleeding is almost always present once ulcerative colitis is well developed, and, in addition, mucous is frequently observed in the stool. Patients will often complain of tenesmus and have diarrhea. However, if the disease is limited to the rectum, patients may present with constipation, rather than diarrhea, associated with rectal bleeding. For the patient presenting with constipation and rectal bleeding, there is a tendency to presume that the bleeding is hemorrhoidal and the constipation reflects a functional disorder. However, if mucous is observed in the stool, and, in particular, the patient experiences tenesmus, which is unusual in typical irritable bowel syndrome, with hemorrhoidal bleeding, then the suspicion of underlying proctitis has to be great. Abdominal cramping may be absent until the disease is extensive, at least above the distal colon. Additional clinical clues which should be sought out from the history include the presence of arthralgias or frank arthritis, which will be present in up to 10% of patients with ulcerative colitis. Skin lesions

including erythema nodosum and, less commonly, pyoderma gangrenosum occur in this disorder, and both arthritis and erythema nodosum may precede by months or even years the onset of the typical symptoms of ulcerative colitis. Episcleritis and uveitis can be seen in association with ulcerative colitis. The family history as noted above should be obtained and if positive for IBD then the index of suspicion that the patient may have inflammatory bowel disease has to be high. The diagnosis is generally established by the sigmoidoscopic appearance of the colon coupled with a typical history. In contrast to the normal appearing mucosa, with well demarcated vessels and a shiny, pale appearance, the vascular markings in ulcerative colitis are lost due to engorgement of the mucosa with an erythematous appearance. In addition, petechiae, exudate, touch friability and frank hemorrhage may be present. The biopsy may be helpful in distinguishing ulcerative colitis from an acute self-limited infectious process, in that in ulcerative colitis chronic changes including branching of crypts and atrophy and loss of mucin in goblet cells will typically be present. Since treatment is based upon the extent of severity of disease, it is helpful at the initial presentation to document the extent of disease, since topical therapy will usually be used initially for patients whose process is limited to the lower 30 to 40 cm. A full colonoscopy on presentation is generally not warranted unless there is confusion about the underlying diagnosis. The findings described above with regard to an abnormal appearing mucosa are not specific to ulcerative colitis, and other entities including Crohn's disease, radiation colitis, ischemic colitis, a variety of infectious processes and colitis related to drugs all have to be excluded. It is particularly important on initial presentation and during major flare-ups to rule out an infectious etiology. Typically, these include Salmonella. Shigella. Campylobacter as well as Aeromonas and E. coli 0157:H7. Previous antibiotic therapy may cause Clostridium difficile colitis, which may mimic ulcerative colitis, although gross rectal bleeding is not common in this disorder. Some feel that many flares of ulcerative colitis are related to C, difficile infection even in the absence of recent antibiotic exposure. In the immunocompromised patient, cytomegalovirus as well as Kaposi's sarcoma are considerations, since they can mimic ulcerative colitis. With regard to drug-related colitis, the most prominent factor is the use of non-steroidal anti-inflammatory drugs (NSAIDS) . There are a number of patients in whom acute or subacute colitis is caused by NSAIDS, and these agents have the potential of exacerbating known underlying inflammatory bowel disease. Other drugs which may cause a clinical picture resembling IBD include retinoic acid (Accutane), gold therapy and possibly oral contraceptive pills. The literature is sufficiently confused with regard to the effectors of the Pill on IBD that it does not justify stopping the Pill in every woman who develops inflammatory bowel disease. However, if the inflammatory bowel disease came on relatively soon after the onset of taking the Pill and the disease does not respond relatively quickly to standard therapy, then consideration should be given to stopping it. Crohn's Disease The clinical features of Crohn's disease share many similarities with ulcerative colitis, especially when the colon is involved. It should be noted that although rectal bleeding is almost always present with ulcerative colitis once it is well developed, it occurs in only about half of the patients who have Crohn's disease involving the colon. Because of the obstructing tendency of Crohn's disease related to the transmural inflammation, fibrosis and narrowing, it is more likely with Crohn's disease that patients will complain of chronic abdominal pain often related to the

narrowing and partial obstruction. Unlike patients with ulcerative colitis, upwards of a third of patients with Crohn's disease will have significant and symptomatic perineal disease including fistula abscesses and fissures. Weight loss is a feature of even early Crohn's disease, largely because patients feel better when food is avoided. Finally, Crohn's patients may manifest fever in the absence of obvious infection or even obvious intestinal symptoms, and Crohn's disease is one of the unusual causes of a fever of unknown origin. With regard to clinical clues, which may not be forthcoming in the initial history, aphthous ulcers in the mouth are often prominent in Crohn's disease, more so than in ulcerative coliris. Additional clues which are similar to those for ulcerative colitis include joint pain, skin lesions, eye inflammation and, as noted, the family history. With regard to diagnostic evaluation, when Crohn's disease involves the colon, colonoscopy may be necessary to establish the diagnosis, since commonly the rectum and sigmoid are spared and therefore the flexible sigmoidoscopy may well be normal. Barium enema, of course, is an alternative to colonoscopy, although mild early Crohn's disease may be subtle enough to escape detection on barium enema. Endoscopic features of Crohn's disease involving the colon include focal ulcerations adjacent to areas of normal appearing mucosa along with polypoid changes of the mucosa giving it a cobblestone appearance. These features tend to distinguish it from uicerative coliris, which, until it is advanced, tends not to give gross ulcerations and which causes a diffuse area of involvement on any given endoscopic view. With regard to small bowel disease, although on occasion the colonoscope will reach the distal ileum, more often the diagnosis is made on the basis of a small bowel x-ray, with an irregular appearing ileum often with separation of bowel loops. As the process becomes more advanced, the distal ileum narrows, creating a "string sign", which is related partially to fibrosis and partially to edema and spasm. The biopsy in Crohn's disease, unlike that in ulcerative coliris, can be specific in granulomas are present and certain infections and foreign bodies are ruled out. However, the absence of granulomas on biopsy does not exclude Crohn's disease, since they are present in only about 30% of specimens. Distinguishing Crohn's coliris from ulcerative coliris is important. Although standard medical therapies of these disorders are similar, this distinction becomes crucial if colectomy is needed. Moreover, there are some differences with regard to therapy beyond the standard agents, and therefore an attempt should be made to decide which of the two processes is present. The following features will tend to distinguish Crohn's colitis from ulcerative colitis: - If the small bowel is involved, then ulcerative colitis is excluded. - In the remaining patients, if the rectum is spared, then, again, ulcerative colitis is excluded. - A small number of patients will then be left, in which case if bleeding is absent, the diagnosis of Crohn's disease should strongly be suggested. - In the remaining patients, perianal disease, if present, will exclude ulcerative colitis. By this process, one is left with a small percentage of patients who have Crohn's disease that resembles ulcerative colitis. To make this final distinction, consideration should be given to the focality of lesions, the presence of fistula or granulomas. Ultimately, a small proportion of patients remains in whom the diagnosis of Crohn's disease cannot be distinguished from ulcerative colitis. Such patients have features which may resemble both disorders, and these patients are called indeterminant colitis.

Complications Both Crohn's disease and ulcerative colitis are associated with a number of systemic complications. These include eye involvement with uveitis and episcleritis; skin processes such as erythema nodosum and pyoderma gangrenosum, peripheral arthritis which is usually monarticular asymmetric involving the large joints more than the small with no synovial destruction and no subcutaneous nodules and seronegativity, ankylosing spondylitis and, finally, involvement of the biliary tree in which sclerosing cholangitis often with a rising alkaline phosphatase is the most common disorder. A major concern of both patients and physicians caring for the patient is the development of colon cancer. Colon cancer is clearly increased in both ulcerative colitis and Crohn's disease. With regard to ulcerative colitis, the incidence begins to go up seven to eight years after the onset of disease, and the risk of acquiring colon cancer is related to both the duration of the disease as well as its extent. As an example, an episode of panotitis 25 years earlier, even if the disease has been relatively quiescent since then, puts the patient at a high risk for colon cancer. On the other hand, if the disease has been limited to the lower 15 to 20 cm of colon, but has remained active throughout a 25-year period, there is virtually no increased risk for colon cancer. With regard to ulcerative colitis, there is now evidence that involvement of the left colon up to the splenic whose disease extends beyond that point. But, as noted, patients with proctitis and distal colitis appear to be at very little increased risk. Although a variety of studies have given different risk estimates, it is generally agreed that the risk goes up about one half percent per year after years seven to eight for patients who have had disease, at least up to the splenic flexure. The older patient who develops inflammatory bowel disease, therefore, may be at less risk than the patient who develops it at a young age, although the older patient may have an added risk just by virtue of age alone. The risk of colon cancer appears to be about the same whether the patient has ulcerative colitis or Crohn's disease, although carcinoma in Crohn's disease has been less well studied than in ulcerative colitis. In Crohn's disease, about two thirds of colon cancers occur in obviously diseased bowel, while only one third are located in clinically uninvolved bowel. This differs from ulcerative colitis, where carcinoma seems to involve only areas of previously involved bowel. Surveillance colonoscopy is based upon the concept that dysplasia is a predictor of the development of colon cancer or a marker that the cancer is already present. Several prospective studies have associated high-grade dysplasia, with a 30 to 50% chance of colon cancer being present, but not detectable by colonoscopy. It is, therefore, recommended that patients with ulcerative colitis whose disease has extended to the splenic flexure or beyond have a surveillance colonoscopy every two years initially. After a duration of 15 years of disease, annual colonoscopy is recommended. The finding of high-grade dysplasia is an indication for total colectomy. There is increasing feeling that even low-grade dysplasia should be a consideration for total colectomy, although that is not as universally accepted. With regard to Crohn's disease, a similar recommendation is now being made, although there is less data upon which to base that recommendation. Indeed, surveillance colonoscopy can be considered at the time of diagnosis of Crohn's disease, since many patients may have had subclinical disease for a number of years, and, therefore, it is difficult to know the true duration of the inflammatory process involving the colon. The use of colonoscopic surveillance is controversial, since it has not been well proven that

surveillance colonoscopy really impacts on mortality, although there is a suggestion of its benefit from two recent retrospective analyses. Therapy Anti-inflammatory Agents Sulfasalazine has been shown in controlled trials to be effective in active ulcerative proctocolitis regardless of the extent of disease. It is also efficacious in maintaining long-term remission of ulcerative colitis. It has proven useful in Crohn's disease, but primarily when the colon is involved, since controlled trials have not shown efficacy with ileitis alone. However, in the doses studied in controlled trials, it has not been shown to be effective at maintaining remission in Crohn's disease nor in preventing postoperative occurrence after resection and anastomosis. Adverse effects limit the use of sulfasalazine, and these include dyspepsia, nausea and anorexia, which may at times be avoided by either lowering the dose or employing the use of an enteric-coated preparation. For mild allergic reactions such as rash and fever, it may be possible to desensitize the patient by gradually introducing very low doses with progressive increase in dose. However, more severe reactions such as hemolysis, agranulocytosis, male infertility, alveolitis, pancreatitis and pericarditis require stopping the drug. Sulfasalazine consists of sulfapyridine, one of the first sulfonamide drugs linked to 5aminosalicylic acid (5-ASA) via an azo bond. When ingested, about 30% of the drug is absorbed passing through the liver unchanged to be partially excreted in the urine and partially returned to the intestinal tract where it joins the nonabsorbed portion to traverse the intestine until it reaches the colon. There the azo bond is broken by bacterial azo reductases, with release of the sulfa moiety, which is absorbed and metabolized by the liver and excreted, never reaching the distal colon. The 5-ASA moiety, however, is only minimally absorbed, staying within the colon to be excreted in the feces. 5-ASA is the active moiety of sulfasalazine. Topical administration of 5ASA is effective in ulcerative proctitis and distal ulcerative colitis. There are now available both topical 5-ASA enemas, known generically as mesalamine and marketed as Rowasa enemas. In addition, there are Rowasa suppositories available for patients with ulcerative proctitis and distal colitis. For proctitis, a suppository can be used twice a day, with a response expected within several days and a complete remission anticipated in four to six weeks. The suppository can then be tapered to a nighttime use only, and possibly as little as an every-other-night or every-thirdnight usage will keep the patient in remission. A similar protocol is used for patients with distal ulcerative colitis, but Rowasa enemas are used initially nightly and then after a full response is attained in several weeks are tapered to every-other or every-third-night usage. The topical forms of 5-ASA will be helpful for patients with distal colonic disease, but will not in themselves be of use for disease extending beyond 50 to 60 cm in the colon and be of no help for patients with right-sided colitis or small bowel disease. There are now several oral preparations of 5-ASA available. These include delayed release forms of mesalamine including Asacol, which is coated with an acrylic resin, and Pentasa, which puts the 5-ASA in ethylcellulose microspheres. These are then gradually released in the small bowel and colon.

Another form of oral 5-ASA, olsalazine, links the 5-ASA to itself via an azo bond which, as with sulfasalazine, requires bacterial action for the release of the free 5-ASA and so is targeted primarily for the colon. A third form, balsalazide, which links 5-ASA to an inert polymer, is now under clinical investigation, but unlike the above three agents is now commercially available in the United States. The oral agents have been shown to be effective in active ulcerative colitis and in maintaining remission in ulcerative colitis, but are no more effective than sulfasalazine. Since they are considerably more expensive than sulfasalazine, sulfasalazine usually is considered the first choice of oral therapy for such patients. However, for patients who are intolerant or allergic to sulfasalazine, the oral 5-ASA agents become the therapy of choice in active and remitted ulcerative colitis. With regard to Crohn's disease, these agents have been much less well studied. However, it does appear that the slow-release oral 5-ASA agents are effective in Crohn's disease limited to the small bowel as well as the colon, a finding which distinguishes them from sulfasalazine, which has been useful in colonic disease only. Moreover, unlike the findings with sulfasalazine, the slowrelease oral 5-ASA agents appear to maintain remission in Crohn's disease, particularly for patients with ileitis. Most of the side effects of sulfasalazine can be attributed to the sulfapyridine moiety. Indeed, 80 to 90% of patients allergic to sulfasalazine will tolerate an oral or topical 5-ASA preparation. However, in 10 to 20% of such patients, the allergic reaction is due to the 5-ASA moiety, and, therefore, caution must be exercised in switching a patient who has had a severe reaction to sulfasalazine to one of the new 5-ASA agents. Moreover, as the 5-ASA agents are being used with greater frequency, a variety of side effects have been reported including anal irritation with topical diarrhea particularly with the olsalazine form, alveolitis, pericarditis and pancreatitis. In addition, there are a few scattered reports of nephrotoxicity with high-dose oral 5-ASA agents, making it important to monitor the BUN, creatinine and urine analysis in such patients. Corticosteroids Topical corticosteroids in the form of enemas and foams have shown to be useful in ulcerative proctitis and distal ulcerative colitis and with the topical 5-ASA agents can be considered for the first-line therapy. The choice between the 5-ASA and steroid topical therapies is often difficult and usually involves patient preference to not have steroids or the decision to keep patients on long-term maintenance therapy, which mitigates in favor of the 5-ASA product. Currently, the Cortenema is about two thirds as expensive as the Rowasa enema. For patients with more extensive disease who are somewhat sicker, oral prednisone usually in doses of 40 to 60 mg per day has been effective in active disease in both active ulcerative colitis and Crohn's disease regardless of disease distribution. However, as with topical therapy, the standard oral steroids have not been shown to be effective at maintaining remission, and, therefore, every attempt should be made to wean the patient off the steroid once an effect is achieved for active disease, usually within the first two weeks of therapy. For more seriously ill patients who require hospitalization, parenteral steroids in the form of hydrocortisone, prednisolone or methylprednisolone are indicated. There is some evidence that intravenous ACTH

may be more effective in patients who have not recently been on steroid therapy. Budesonide is an enema that appears to be as effective as standard topical hydrocortisone and 5ASA preparations. It has the advantage over standard steroids of not affecting the hypothalamic pituitary access, since only about 10% of it is available to the systemic circulation due to rapid metabolism on first pass through the liver. Recently, studies with a slow-release oral budesonide preparation have shown that it is more efficacious than placebo in active Crohn's ileitis and ileocolitis and about as effective as oral prednisolone, but with only about half the chance of developing a side effect. It remains unclear whether oral budesonide will be effective at maintaining remission in Crohn's disease and, if used long term, whether side effects similar to those with standard steroids will begin to appear. These drugs remain under investigation. Antibiotics Metronidazole has been shown to be effective in active Crohn's disease involving the colon in doses as low as 10 mg per kg per day. The long-term efficacy of metronidazole in maintaining remission in Crohn's disease has not been studied. In open trials with higher doses of metronidazole at a level of 20 mg/kg/day, the drug has been effective in perineal disease, although withdrawal of therapy usually leads to recurrent symptoms. Metronidazole has not been shown to be effective in active ulcerative colitis, although one study suggests that it was as effective as sulfasalazine in maintaining remission in ulcerative colitis. Recently, there has been increasing attention focused on the use of a variety of antibiotics other than metronidazole in active Crohn's disease including patients with ileal disease. Ciprofloxacin has been described in a couple of open trials and has been successful in improving the status of patients with active disease. A small placebo-controlled trial suggested efficacy for clarithromycin at inducing and prolonging remission. An earlier study showed similar efficacy in an open trial for ampicillin, cephalexin, tetracycline and other broad-spectrum antibiotics. Controlled trials of these agents are still awaited, although their use should be considered, particularly in patients who do not respond to 5-ASA agents. Immunomodulator Therapy A number of drugs which modulate the immune system have been looked at in inflammatory bowel disease. The agents in most widespread use are azathioprine and 6-mercaptopurine (6-MP). The two can be used interchangeably, since azathioprine is metabolized to 6-MP in the liver. Both agents have been shown to be useful in active Crohn's disease regardless of disease distribution and in maintaining remission in Crohn's disease. More recent studies have shown similar efficacy of these drugs in active ulcerative colitis and in maintaining remission in ulcerative colitis. There is currently a study to look at the effectiveness of 6-MP on preventing postoperative recurrence in Crohn's disease. Side effects with these agents have been surprisingly minimal, with pancreatitis and leukopenia being the major short-term side effects. There have been a few cases of lymphomas described with their use, but it is not clear whether the incidence on these agents is any higher than in patients not on such drugs, since lymphoma may be increased in Crohn's disease irrespective of therapy. Nonetheless, caution needs to be exercised in the use of these

agents, and the white blood count should be monitored frequently. There is a suggestion that cyclosporin may be helpful in oral form in active Crohn's disease; however, the relapse rate upon withdrawal is great, and since low-dose cyclosporin is not effective at maintaining remission in Crohn's disease, its utility in this disorder is somewhat in doubt. Intravenous cyclosporin may be useful in healing refractory fistulas in Crohn's disease, but, again, the relapse rate upon withdrawal is high. Oral forms of cyclosporin had only limited utility in active ulcerative colitis of a mild to moderate form. The major role for cyclosporin appears to be in patients with severe active ulcerative colitis which is not responding to standard high-dose parenteral corticosteroids. In two recent trials, IV cyclosporin given as a continuous infusion at either 2 mg/kg/day or 4 mg/kg/day was effective in bringing the majority of patients into a remission. The long-term effectiveness of oral cyclosporin in such patients and the ultimate avoidance of colectomy is still under study. Finally, methotrexate has appeared useful in open trials in both active Crohn's disease and active ulcerative colitis. It does not appear to be of use in maintaining remission in ulcerative colitis and is only of marginal benefit in maintaining remission in Crohn's disease. A recent placebo-controlled trial suggests that methotrexate is useful in active Crohn's disease, particularly in patients who had been dependent on doses of prednisone over 20 mg/day. Long-term controlled trials of this drug are awaited. Miscellaneous Agents Nicotine patch has been shown to be useful in one controlled trial in active left-sided ulcerative colitis. This is based on the previously noted epidemiologic information - that smoking seems to protect an ulcerative colitis. Short-chain fatty-acid enemas, particularly butyrate, which provide a fuel for epithelial cells, have been studied in open trials and appear to be effective in distal active ulcerative colitis. A whole other array of topical agents including Bismuth, nicotine and lidocaine have been shown to be effective in open trials, whereas a number of oral agents or parenteral agents including allopurinol, anti-TNF antibodies, interleukin 10 and interleukin II, heparin and tacrolimus all have appeared promising, but await further controlled trials before their use can be advocated in IBD. Nutritional Therapy In ulcerative colitis, enteral and parenteral nutrition serves only as an adjunct to drug therapy for ulcerative colitis. However, with regard to Crohn's disease, they can be used as primary therapy to induce remission in about 65 to 70% of patients. Unfortunately, the recurrence rate upon reinstitution of regular food is quite higher than that for standard drug therapy. However, enteral and/or parenteral therapy may be lifesaving for patients with short bowel syndrome and is important in promoting growth failure in children. Surgery Medical therapy is sufficient for about 80% of patients with ulcerative colitis, but the remainder will ultimately need a colectomy for either intractable symptoms, the development of a complication such as massive bleeding or toxic megacolon or the development of dysplasia or of

colon cancer. The standard surgical therapy for ulcerative colitis has been total colectomy with a permanent ileostomy. Now the ileoanal anastomosis with pouch has emerged as the procedure of choice for most patients, since it spares the anal opening and allows for normal continence. Patients usually have five to six bowels movements a day, but the majority are fully continent and their stool frequency can be controlled with Metamucil and antimotility agents. Pouchitis occurs in 20 to 50% of patients, but can usually be treated with metronidazole, ciprofloxacin or other antibiotics. This procedure cannot be offered to patients with Crohn's disease because of the high recurrence rate of the disease in the small bowel ileal pouch. An innovative surgical therapy for Crohn's disease is strictureplasty for those patients with multiple small bowel strictures. This avoids unnecessary resection. Also, the concept in Crohn's disease is for minimal resection, removing only grossly involved areas of bowel and not being concerned with the removal of all microscopic disease. For Crohn's surgery, the most common procedure is a resection with an anastomosis. Unfortunately, the recurrence rate after such surgery is high, occurring with a frequency of about 10% per year. However, studies have emphasized that resection in Crohn's disease does improve the quality of life, and the majority of patients have much less psychosocial dysfunction, even years after surgery and even after clinical recurrence. References Podolsky DK. Inflammatory Bowel Disease. N Engl J Med 1991; 325:928-37,1008-16. Peppercorn MA. Inflammatory Bowel Disease. Gastroentero1ogy Clinics of North America 1995; Vol 24, No 3. Hanauer SB. Inflammatory Bowel Disease - Medical Therapy. N Engl J Med 1996;335:841-8. Mowschenson PM. New surgical approaches in IBD. In Peppercorn MA (ed), Seminars in Colon and Rectal Surgery, 1993. pp 25-36.