Clinical Manifestations
The clinical manifestations of IBD can be conÂveniently considered as those relating directly to the bowel disease and the systemic response to it and those that are extraintestinal and of more obÂscure origin.
Intestinal Manifestations. The cardinal maniÂfestations of acute UC are diarrhea, rectal bleedÂing, fever, weight loss, and abdominal pain. The disease can be mild with only a gradual slight inÂcrease in the number of stools and can be limited anatomically to the rectum (ulcerative proctitis). Conversely in a minority of patients (10 to 15 per cent) it begins explosively, so that the patient is acutely ill and requires immediate hospitalization to prevent complications of toxic megacolon such as shock, hypokalemia, and colonic perforation. Depending upon the severity of the diarrhea and the extent of ulceration and inflammation, the paÂtient may exhibit electrolyte abnormalities (parÂticularly hypokalemia), anemia, leukocytosis, fever, and all of the symptoms and signs of toxÂicity—e.g., weakness, anorexia, tachycardia, and hypotension. The abdomen may be distended and diffusely tender, but generally no masses are felt. Most patients with UC have remissions of their symptoms that may last for months or even years, followed by recurrent acute exacerbations.
In Crohn’s disease the onset of symptoms is often more subtle than in UC, and the type of presÂentation is influenced by the anatomical site of the major lesion. If the ileum is primarily inÂvolved, the symptoms may suggest low-grade inÂtestinal obstruction with postcibal colicky pain, modest diarrhea, and sometimes the presence of a right lower quadrant palpable mass. Rectal bleeding is rare in all forms of Crohn’s disease, although occult blood loss is not uncommon. The onset of Crohn’s ileitis may simulate acute apÂpendicitis in a young person. With colonic inÂvolvement diarrhea may be more prominent as well as perirectal disease, comprising fissures, fisÂtulas, and perirectal abscesses. Colonic Crohn’s disease is also associated with a higher incidence of the extraintestinal manifestations described below. Because of the thickened intestinal wall in Crohn’s disease, “toxic megacolon” does not occur and free perforation as opposed to fistula formation is uncommon. In brief, consistent with their respective pathological lesions, Crohn’s disÂease is more likely to produce fistulas or obstrucÂtion and less likely to produce hemorrhage or perÂforation than is UC.
Extraintestinal Manifestations. Similar exÂtraintestinal manifestations may occur with UC and witi Crohn’s disease of the colon (Table 40-2). These will be considered together and disÂcussed briefly. Nutritional deficiencies, occurring secondary to anorexia, fever, diarrhea, and blood loss, may result in growth retardation or severe weight loss. IBD may be associated with two forms of arthritis: (a) nondeforming acute inflammatory arthritis of unknown cause affecting large joints more frequently, and (b) sacroiliitis and ankylosÂing spondylitis, which occur in those patients who also have HLA-B27. The former tends to parÂallel the colonic disease; the latter generally perÂsist, even after colectomy for UC. Hepatobiliary abnormalities are diverse in nature and severity. Many patients have fatty liver and mild perichoÂlangitis, often manifested chemically only by anelevated serum alkaline phosphatase. Rarely scleÂrosing cholangitis involving both intrahepatic and extrahepatic ducts may develop, presenting the full picture of obstructive jaundice and leading to cirrhosis. There is an increased incidence of choÂlelithiasis, especially with Crohn’s disease of the ileum, thought to be secondary to deficient ileal reabsorption of bile salts. Primary carcinoma of the bile ducts is rare but is increased in incidence. Ocular manifestations of IBD include episcleritis, iritis, and uveitis. Erythema nodosum may occur in about 5 per cent of patients, especially in women, and a peculiar indolent necrotic skin leÂsion termed pyoderma gangrenosum may be found in about 1 to 2 per cent, especially with active UC. Aphthous ulcers of the buccal mucosa are not infrequent, particularly in Crohn’s disease. Renal lesions may include (a) kidney stone diaÂthesis, especially calcium oxalate stones due to absorptive hyperoxaluria in Crohn’s disease, (b) obstructive uropathy or fistulas to the urinary tract in Crohn’s disease, (c) kaliopenic nephroÂpathy, or, very rarely, (d) amyloidosis. An inÂcreased tendency to develop thrombophlebitis has also been noted.
These extraintestinal manifestations may rarely precede overt bowel symptoms or may be the most important source of disability. Most of them tend to remit with improvement of colitis or following colectomy except for sclerosing cholangitis, cirÂrhosis, and sacroiliitis/spondylitis.