GI Consult: Ulcerative Colitis

Topics include sigmoidoscopy versus colonoscopy, endoscopic findings that help with the differential diagnosis, pharmacotherapeutic options, and what to do about polyps.

By Charles Maltz, MD

When should I consider ulcerative colitis as a diagnosis for a patient with rectal bleeding?

Unless an infectious cause appears likely, as suggested by clinical presentation or positive stool culture, all patients with new-onset rectal bleeding should undergo an endoscopic evaluation of the large bowel. For the young patient with apparent distal rectal bleeding (as suggested by red blood on toilet paper and coating the stool), a flexible sigmoidoscopy may suffice. If there is any question as to disease more proximal in the colon, a full colonoscopy should be performed.

In a patient who appears ill with possible colitis, an unprepped examination of the rectum is often sufficient to establish the diagnosis. A complete colonoscopy to evaluate the extent of disease can be done after the colitis has quieted down.

The endoscopic picture of ulcerative colitis varies, ranging from loss of vascular markings with mild friability to purulent exudates with sloughing of mucosa. Areas of the colon that appear inflamed on endoscopy should be biopsied. A normal biopsy rules out ulcerative colitis as the diagnosis. However, a patient who has been receiving topical treatment for colitis before endoscopy may not have rectal inflammation.

Is the rectum always involved in ulcerative colitis?

In general, yes. More than half of patients with ulcerative colitis will have proctitis, which is disease limited to the rectum. About another third will have disease limited to the left colon; the remaining 20% will have total (or universal) colitis.

How helpful is rectal biopsy in diagnosing colitis?

Rectal biopsy should be done in all patients in whom colitis is suspected but not yet diagnosed. The hallmark of colitis is the biopsy finding of cryptitis and crypt abscesses. However, these may also be found in Crohn's disease and acute infectious colitis. The presence of granulomas establishes the diagnosis of Crohn's colitis, but they are found in fewer than 25% of biopsies of Crohn's disease patients. The biopsy is most useful in confirming that colitis is actually present and ruling out amoebae, cytomegalovirus, or other infection.

What other types of colitis have an endoscopic profile similar to ulcerative colitis?

Crohn's colitis, acute infectious colitis, and ischemic colitis can mimic ulcerative colitis. Infectious entities such as Salmonella, Shigella, Campylobacter, Clostridium difficile, and Escherichia coli O:157/H7, as well as amoebae, can cause such symptoms as crampy abdominal pain and bloody diarrhea. Although stool studies may pick up the presence of amoebic infection, in some cases it is only noted on examination of a biopsy specimen. Just as it is important to rule out infectious causes in all new cases of ulcerative colitis, it is important to keep infection in mind as a possible etiology in exacerbations of pre-existing colitis.

Is it important to distinguish ulcerative colitis from Crohn's colitis?

The treatment of ulcerative colitis and Crohn's colitis is quite similar. Differentiation becomes more important if surgery is contemplated. Ulcerative colitis is generally curable by total colectomy, while Crohn's colitis is likely to recur in the small bowel after the colon is removed.

Are the new serologies helpful?

Serologic markers such as ANCA, ASCA IgA, ASCA IgG, and anti-OmpC are sometimes useful as an adjunct in classifying colitis that does not easily fit into the ulcerative or Crohn's subtypes. However, most clinicians rely on endoscopic and/or radiologic confirmation to determine the presence or absence of inflammatory bowel disease.

What are the treatment goals in managing ulcerative colitis?

The goals should be to achieve and maintain remission without serious medication side effects, especially with steroid therapy. Once the diagnosis is established, the physician should tailor the treatment to the location, severity, and symptoms of the disease. The rare patient with distended colon, fever, tachycardia, and anemia (toxic megacolon) should be admitted for intravenous treatment and surgical consultation. Patients who are less ill can often be treated with a combination of oral and rectal medications.

What medications are used to treat ulcerative colitis?

Medications for ulcerative colitis include mesalamine (systemic or topical), corticosteroids (systemic or topical), and immunomodulatory agents, such as azathioprine/6-MP, cyclosporine, and infliximab. Whether mesalamine or oral prednisone is used depends on the severity of the colitis. The type of mesalamine must be chosen with the understanding that, as a topical agent, it must be delivered to the inflamed colon. Thus, for colonic disease, the most appropriate choice will probably be a coated version of mesalamine that only becomes available in the colon, or mesalamine that is covalently bound to a carrier such as sulfapyridine (sulfasalazine) or a non-sulfur carrier (balsalazide). It is often helpful to combine oral and rectal mesalamine to ensure that the entire colon is covered.

Do antibiotics or infliximab have any role in ulcerative colitis?

Although helpful in Crohn's disease, antibiotics are not useful in ulcerative colitis patients, except for those with toxic megacolon who are at risk for perforation. There are no data from controlled studies on infliximab, but there are anecdotal reports suggesting that half of patients refractory to steroids have responded to infliximab.

Is distal disease managed differently than universal colitis?

In many ways, these patients are managed similarly. The patient with proctitis will often have a significant problem with tenesmus (painful spasms of the anal sphincter), which may respond to topical medication, such as mesalamine enemas or suppositories. Limited left-sided disease, however, may prove as refractory to treatment as total colitis and may require colectomy.

What is the risk of colon cancer in the patient with ulcerative colitis?

Ulcerative colitis increases the risk of colorectal cancer. The magnitude of the risk depends on how much of the colon is affected and how long the disease has been present. With total colitis, the risk starts to increase when the patient has had the disease for eight to 10 years. After that time, the risk is estimated to be 0.5% to 1.0% per year. An estimated 8% of patients with total colitis will develop cancer after having had the disease for 20 years. The risk is lower in left-sided colitis and essentially unchanged from normals in patients with proctitis. There is also some evidence that patients who take mesalamine chronically have a lower incidence of colorectal cancer.

Because colorectal cancer in a patient with ulcerative colitis is often preceded by or associated with dysplasia, periodic colonoscopy with multiple biopsies is advised. The biopsies, which should be reviewed by one or more pathologists with expertise in this area, are read as either high-grade dysplasia, low-grade dysplasia, indefinite for dysplasia, or no dysplasia. Cancer or high-grade dysplasia mandate colectomy; low-grade dysplasia is a more complex issue.

How should a polyp be managed in a patient with chronic ulcerative colitis?

It depends on whether the polyp is a pseudopolyp, adenoma, or a hyperplastic polyp. Pseudopolyps have characteristic features, such as a frondlike appearance or a coating of inflammatory exudates. The experienced endoscopist may be able to differentiate the various types by their appearance, but occasionally it is necessary to remove a polyp for histologic examination.

The presence of an adenoma, which is by definition dysplastic, in a patient with chronic ulcerative colitis presents a quandary. Should the adenoma simply be removed with colonoscopy as would be done in a patient without colitis? Or should the entire colon be removed because of the risk of cancer? If the patient has a pedunculated polyp of typical appearance, without any dysplasia in the surrounding mucosa, then a simple polypectomy should suffice.

What is the role of surgery in ulcerative colitis?

About one quarter of patients with ulcerative colitis will need a colectomy, which is generally curative. Indications for surgery for ulcerative colitis include intractability, cancer or significantly increased cancer risk, and toxic megacolon. In a young person with longstanding refractory disease, surgery should be considered as an alternative to open-ended treatment with a potentially toxic medical therapy.