Inflammatory bowel disease

Chapter 16 INFLAMMATORY BOWEL DISEASE




KEY POINTS


Ulcerative colitis:














Crohn’s disease:
















ULCERATIVE COLITIS


The diagnosis of ulcerative colitis (UC) is relatively easy since the inflammatory process almost always involves the rectum and generally causes urgency and bleeding. People generally present promptly when rectal bleeding is noted, but the onset may be insidious and the presentation delayed. The bleeding is persistent rather than intermittent as would be expected with local anal problems, such as haemorrhoids. Proctitis may also cause discomfort, increased frequency and a change in the consistency of the stools. Rarely, the presenting symptom may be constipation. As the disease extends more proximally and more of the mucosal surface area is involved, the symptoms become more severe: diarrhoea increases (with looser or more frequent stools) and pain may become more prominent. Systemic symptoms may also develop.


In a significant minority of patients, the presentation is as a fulminant colitis with features including fevers, anorexia and weight loss; such patients are at risk of developing life-threatening complications including toxic megacolon, perforation, peritonitis and haemorrhage, and require urgent assessment and treatment in specialist centres. Given the large surface area of the colon, it is not surprising that ulcerative pancolitis results in blood loss and consequent anaemia, protein loss, hypoalbuminaemia and fluid and electrolyte losses, and the associated metabolic disturbances.


The extraintestinal manifestations of UC may affect the skin, joints, eyes and/or the liver (Table 16.2). These may occur before, during or after the onset of gut symptoms and may be associated with disease activity. These are generally more common in UC than Crohn’s disease.


TABLE 16.2 Extraintestinal manifestations of ulcerative colitis



























Skin Erythema nodosum
Pyoderma gangrenosum
Aphthous stomatitis
Joints Type 1 peripheral osteopathy*
Type 2 arthritis**
Sacroileitis
Eyes Iritis
Uveitis
Episcleritis
Liver Primary sclerosing cholangitis

* Acute self-limiting inflammation affecting <5 joints, lasting <5 weeks and associated with symptom relapse and with other extraintestinal manifestations.


** Chronic arthritis affecting five or more joints with a median duration of symptoms of 3 years, and associated with uveitis but not erythema nodosum.


When assessing patients with suspected UC, particular attention should be paid to the haemodynamic status for evidence of significant intravascular losses and the abdominal examination for distension, tenderness and/or signs of peritonism. There may also be signs of anaemia or significant weight loss. Sigmoidoscopy will show an abnormal rectal mucosa: there will be erythema, loss of the normal vascular pattern, contact bleeding and mucopus or blood in the lumen. In more severe disease there will be extensive ulceration and pseudopolyp formation.


The differential diagnosis is considered in Table 16.3.


TABLE 16.3 Differential diagnosis of ulcerative colitis and Crohn’s disease
















The diagnosis depends upon the exclusion of infective and other causes of colitis and the demonstration of the typical endoscopic and histological features of UC. Stool cultures and microscopy and studies for Clostridium difficile toxin should be sent. If there is a history of overseas travel, a warm stool smear should be performed to exclude amoebic dysentery. Patients suffering from UC may also have relapses secondary to gastrointestinal infections or non-steroidal antiinflammatory drug (NSAID) usage.


Ulcerative colitis can generally be differentiated from Crohn’s disease using endoscopic and pathological criteria (Table 16.1). UC affects the colon exclusively and almost always involves the rectum from which it extends proximally in continuity. Sigmoidoscopy will show evidence of proctitis although occasionally patients can have ‘rectal sparing’, particularly if there has been use of corticosteroid or 5-aminosalicylate enemas. Biopsies will show that the inflammation involves the more superficial layers of the mucosa, macrophages are less common and granulomata are not present. Sigmoidoscopic biopsies will help differentiate between UC and other causes of colitis, such as ischaemic colitis and radiation colitis.


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Mar 29, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Inflammatory bowel disease

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