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A General considerations

Two major types of idiopathic inflammatory bowel disease (IBD) may cause colitis of the large bowel: CD and UC.

1.Presentation. There is considerable overlap in the presentation of these diseases (Table 13-4). In approximately 15% of patients with idiopathic colitis, a distinction between the two cannot be made on pathologic or clinical grounds. In such situations, the disease is called indeterminate colitis.

2.Etiology of both diseases remains unknown.

a.Genetic, environmental, infectious, and autoimmune mechanisms have been suggested, but a clearly defined cause has not been identified.

b.Both diseases can occur at any age, but they tend to be diseases of young adults.

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TABLE 13-4 Inflammatory Disease of the Colon

c.It is helpful to distinguish between the two types of colitis, because the medical and surgical treatments are slightly different for each.

3.Serologic markers can be a useful tool for the confirmation of IBD. Perinuclear antineutrophil cytoplasmic antibody (pANCA) and anti–Saccharomyces cerevisiae antibodies (ASCA) are two antibodies frequently detected in the serum of IBD patients. pANCA has been observed in 60%–70% of patients with UC but only in 5%–10% of CD patients and in 2%–3% of the general population. Conversely, positivity for ASCA is typically seen in 60%–70% of CD patients, in 10%– 15% of those with UC, and in 5% of the general population.

B Ulcerative colitis

1.Important features

a.Inflammation. Mucosal inflammation (as opposed to transmural inflammation) occurs, as does rectal inflammation. The rectum is virtually always involved, with inflammation extending proximally for variable distances. Inflammation is continuous; that is, there are no skipped areas of normal mucosa between inflamed segments.

b.Involvement. There is usually no anal or perianal disease in patients with UC. Anal abscesses, fistulas, and fissures are rare. There is no involvement of the small bowel.

c.Histology. Crypt abscesses may be present but not granulomas. Pseudopolyps may be present.

d.Extraintestinal manifestations of the disease may be present, including:

1.Ankylosing spondylitis and sacroileitis

2.Peripheral arthritis

3.Erythema nodosum and pyoderma gangrenosum

4.Aphthous stomatitis

5.Iritis and episcleritis

6.Sclerosing cholangitis

e.Risk for colon cancer occurs in patients with chronic disease.

1.The risk is minimal until after 10 years of onset, and then it increases by approximately 2% each year thereafter.

2.The risk is minimal in patients with disease limited to the rectum and is highest in patients with pancolitis.

3.Dysplasia of the mucosa is associated with an increased risk of cancer.

4.Patients who have had UC for longer than 10 years should have an annual surveillance colonoscopy with multiple mucosal biopsies to search for dysplasia.

5.Cancers in patients with UC are flat, invasive lesions and are not readily identified by barium enema.

2.Clinical presentation

a.Bloody diarrhea is the most common symptom. Rarely, bleeding may be massive and life threatening.

b.Mucus and pus may accompany the passage of loose stools.

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c.Cramping abdominal pain often occurs.

d.Malaise, fever, weight loss, and anemia are common.

e.Severity of disease ranges from occasional episodes of diarrhea to fulminant colitis with toxic megacolon, which is characterized by:

1.Dilatation of the transverse colon

2.Abdominal pain, tenderness, and distention

3.Fever, leukocytosis, and hypoalbuminemia

4.Significant risk of colonic perforation

3.Evaluation depends on the severity of the disease. Mild cases can be evaluated on an outpatient basis, whereas fulminant colitis with toxic megacolon is a life-threatening situation requiring hospitalization, intensive medical treatment, and emergency surgery if medical treatment fails.

a.Proctoscopy is the most valuable test to establish the diagnosis.

1.Mucosal inflammation beginning at the level of the dentate line is highly suggestive of UC.

2.In the presence of fulminant colitis, colonoscopy and barium enema should be avoided because these tests may worsen the condition and lead to toxic megacolon.

3.Mucosal biopsies should be taken to confirm the diagnosis. Such biopsies are also helpful in distinguishing UC from Crohn's colitis and infectious colitis.

b.Abdominal radiographs should be obtained if abdominal tenderness is present and symptoms are severe to rule out colonic dilatation.

c.Stool samples should be cultured for pathogens and examined for ova and parasites.

d.Serologic markers for IBD, mainly pANCA (see Chapter 13, VII A 3)

e.If symptoms are mild, the entire colon should be evaluated by colonoscopy and barium enema.

f.Small bowel contrast studies should be obtained to rule out small bowel involvement, which would indicate CD.

4.Medical treatment

a.Steroids are effective for short-term treatment, but side effects prevent their long-term use.

b.Sulfasalazine remains the main therapeutic agent. It is recommended even if disease is in remission because it decreases the incidence and severity of a recurrence.

c.Aminosalicylates (5-aminosalicylic acid [5-ASA]) are beneficial to patients who are allergic to sulfasalazine.

d.Immunosuppressive agents include:

1.6-Mercaptopurine

2.Azathioprine

3.Methotrexate

4.Intravenous cyclosporine

e.Broad-spectrum antibiotics are indicated for patients with fulminant colitis and toxic megacolon.

f.TPN may be required for patients with severe debilitating disease, usually to prepare the patient for surgery.

5.Surgical treatment

a.Indications

1.Hemorrhage

2.Fulminant colitis or toxic megacolon that is not responsive to intensive medical treatment

3.Debilitating disease that is not refractory to medical treatment

4.Colonic stricture (at least 30% incidence of cancer)

5.Dysplasia or cancer

b.Procedures

1.Total proctocolectomy with a permanent ileostomy

2.Proctocolectomy with anal sphincter preservation and ileal pouch anal anastomosis (restorative proctocolectomy)

a.This operation is the most common for UC. It is usually accompanied by a temporary ileostomy, which is closed 10 weeks after the initial operation.

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b.This operation is contraindicated for patients with CD because of the high incidence of recurrent diseases in the ileal pouch.

3.Abdominal colectomy with closure of the rectal stump

a.This procedure is indicated for patients with fulminant colitis.

b.This procedure is helpful in patients with indeterminate colitis, because it allows examination of the entire colon to distinguish between CD and UC.

c.Restorative proctectomy with an ileal pouch anal anastomosis can be performed at a later time.

4.Ileostomy and blowhole colostomy. This operation is rarely used. The indication is life-threatening toxic megacolon when the colonic wall is too thin and friable to permit resection without rupture. In such situations, the colon is decompressed with a skin-level transverse colostomy, and an ileostomy diverts feces from the colon. After the patient has recovered from the fulminating illness, the standard operations for UC may be performed.

5.Total proctocolectomy and continent (Kock) ileostomy. The main indication for this procedure is a patient who has already had a total proctocolectomy and is allergic to the ileostomy appliance.

a.In this procedure, an ileal pouch is fashioned with a nipple valve that is attached to the abdominal wall and requires intubation to evacuate the ileum several times daily.

b.This operation is associated with a high incidence of complications, usually associated with the nipple valve.

C Crohn's (granulomatous) colitis

1.Important features

a.Inflammation

1.Transmural inflammation. The full thickness of the bowel wall is inflamed.

2.Noncontinuous inflammation. “Skip areas” of normal bowel may separate inflamed regions (another term for this disease is segmental colitis).

b.Involvement. Rectal sparing may be present. Disease does not always involve the rectum. The small bowel is frequently involved (especially terminal ileum). Anal or perianal disease (e.g., fistulas, abscesses, fissures) may be present.

1.Approximately one third of all patients with CD develop anal disease.

2.Anal disease is more common in patients with colon disease (50%) than in patients with small bowel disease (25%).

c.Histology. Granulomas are present in 30%–50% of cases. Linear ulcers may join transverse fissures to give a “cobblestone” appearance to the mucosa.

d.Extraintestinal manifestations are generally the same as for UC, except that sclerosing cholangitis is less common than with UC.

e.Risk for cancer in the diseased segments is increased but less than with UC.

2.Clinical presentation

a.Diarrhea (with diffuse colonic disease) is common.

b.Cramping abdominal pain and right lower quadrant tenderness (with ileocolic disease) are common.

c.Malaise, fever, weight loss, and leukocytosis are common.

d.Abdominal abscess (usually right lower quadrant) may occur.

e.Fistulas may occur between the involved bowel and the bladder, vagina, skin, or other segments of intestine.

f.Anal abscess or fistula is a presenting symptom in 5% of cases.

g.Fulminant colitis may be as severe as UC (see VII B 2 e).

1.The colon usually does not dilate (“megacolon”) with fulminant CD, which is thought to be due to the transmural inflammation with thickening of the wall.

2.Patients with fulminant colitis must be treated as vigorously as patients with UC and megacolon. Risk of perforation is the same as in those conditions.

3.Evaluation. As with UC, evaluation depends on the severity of the disease.

a.Abdominal examination is important to evaluate areas of tenderness or mass.

b.Anorectal examination should detect abscesses, fissures, or fistulas.

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c.Proctoscopy is important. If rectal mucosa is not involved, UC is essentially excluded as a diagnostic possibility.

d.Serologic markers for IBD, mainly ASCA (see VIIA3).

e.Stool samples should be cultured and examined for ova and parasites.

f.Barium studies of the small bowel and colon are indicated to determine the extent of disease.

g.Colonoscopy is helpful to evaluate the extent of colonic involvement.

h.A CT scan is helpful if abdominal or pelvic abscess is suspected.

4.Medical treatment

a.Steroids are helpful for acute disease. Budesonide, a rapidly metabolized glucocorticoid with high topical activity and poor systemic absorption, has been shown to be effective in inducing remissions in patients with CD, with less adrenal suppression than traditional steroids.

b.Immunosuppressive agents appear to provide clinical improvement, steroid sparing, and fistula healing in patients with active CD:

1.6-Mercaptopurine

2.Azathioprine

3.Methotrexate

4.Intravenous cyclosporine

c.Infliximab therapy, monoclonal antibodies to the proinflammatory cytokine tumor necrosis factor (TNF), is indicated for reducing signs and symptoms and inducing and maintaining clinical remission in patients with moderately to severely active CD and for reducing the number of draining enterocutaneous and rectovaginal fistulas and maintaining fistula closure in patients with fistulizing CD.

d.TPN permits bowel rest and induces remission in some patients with significant CD. This remission rate is much higher than the rate for patients with severe UC treated by TPN.

e.Broad-spectrum antibiotics are beneficial to decrease luminal bacterial concentrations, tissue invasion and cellulitis, and bacterial translocation.

f.Metronidazole and ciprofloxacin appear to be beneficial for treatment of anal disease.

5.Surgical treatment

a.Indications

1.Intestinal obstruction

2.Anorectal abscesses or fistulas that require special considerations (pus should be drained, but large incisions are avoided to prevent sphincter injury)

3.Abdominal abscesses, which are preferably drained percutaneously with CT guidance

4.Fistulas between the intestine and bladder, skin, bowel, or vagina (there have been reports of such fistulas closing after treatment by immunosuppressive agents)