Crohn’s disease

18 Crohn’s disease





Questions



image What area is affected by Crohn’s disease?

image What are the differences between Crohn’s disease and ulcerative colitis?

image What are the features found on small-bowel barium enema?

Crohn’s disease is a chronic transmural inflammatory disease that can affect any part of the gastrointestinal tract from mouth to anus. The incidence is equal in males and females and it typically affects adults aged 20–40 years. It is a transmural process, where inflammation affects the whole thickness of the bowel wall.




Aetiology


The causes of Crohn’s disease are unknown, although possible associations are:


image genetic: twin studies have identified the gene NOD2

image infection: some current thought implicates a bacterial infection (Mycobacterium avium paratuberculosis)

image environmental: cigarette smoking increases risk three times (opposite for ulcerative colitis); diets high in sugar and low in fibre are implicated.


Pathology


The small bowel (terminal ileum) is the most commonly affected site, followed by the perineum (resulting in anal sepsis) and then the colon (Crohn’s colitis):


image transmural inflammation: may cause fistulae

image skip lesions are common

image mucosal oedema and fibrosis (which follows healing) can cause strictures and then small-bowel obstruction

image non-caseating granulomas are pathognomonic (although not always present).

Figure 3.18.1 shows the distribution and micropathology of Crohn’s disease and ulcerative colitis.


image

Fig. 3.18.1 Crohn’s disease and ulcerative colitis (UC) showing the distribution (A) and the micropathology (B).



Clinical features


Presentation in infants may be as failure to thrive (growth retardation). Features are:


image general: triad of recurrent diarrhoea, colicky abdominal pain and weight loss
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Jul 3, 2016 | Posted by in MUSCULOSKELETAL MEDICINE | Comments Off on Crohn’s disease

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