Complications
The complications associated with IBD have been largely discussed as part of the clinical manifestations or of the extraintestinal manifestations of these diseases. In addition to the more specific and acute complications such as hemorrhage or perforation, one must be concerned about some of the longterm nonspecific problems such as retardation of growth in children, malnutrition, weakness, lassitude, recurrent pain, and depression. These are complications of many chronic debilitating diseases. Two other complications, alluded to previously and found mostly but not exclusively with UC, will be further described in brief.
Toxic Dilatation of the Colon (Toxic Megacolon). This complication, which represents perhaps the extreme range of acute UC, describes the presence of a markedly distended atonic colon with attenuation of its wall thickness, usually associated with signs of systemic toxicityhypotension, tachycardia, fever, and leukocytosis. Diarrhea may be diminished rather than enhanced, because of loss of colonic motor function. Hypokalemia and hypoalbuminemia are common. Toxic megacolon may occur spontaneously or be induced by injudicious use of drugs given to diminish diarrhea, by preparation for a barium enema examination, or by hypokalemia. The diagnosis is usually made with a plain film of the abdomen showing a colonic diameter greater than 6 cm, usually seen in the transverse colon. There is an immediate and continuing danger of perforation until the dilatation is reversed. The treatment of this medical emergency has been described above.
Carcinoma of the Colon. A general discussion of carcinoma of the colon is found in Chapter 41. There is a special danger of neoplasia in IBD, particularly in chronic UC. The incidence of carcinoma in UC relates to two variables: (a) the presence of extensive mucosal disease, i.e., pancolitis, and (b] the duration of active colitis. The incidence begins to rise steeply after 10 years of active disease. Carcinoma complicating UC has the following characteristics as compared to that occurring spontaneously: (a) it is distributed more evenly in the colon, (bj it is more likely to occur in multiple sites, (c) it is usually discovered at a more advanced stage and has a worse prognosis,and (d) it is more difficult to diagnose because its associated symptoms are mimicked by those of the underlying disease. Because of this it is imperative to institute long-term followup protocols in patients with chronic pancolitis, using colonoscopy and biopsies of suspicious lesions and of the colonic mucosa in general. The latter may show the development of dysplastic changes, thought to be premalignant, and therefore suggest the advisability of preventive colectomy.