I have grouped these to inflammatory bowel diseases together in recognition toof the possible similarities toin their appearances on abdominal plain film. They are not the same disease process.

Pathology

Crohn's disease is an inflammatory disaease of the gastrointenstinal tract. The causitive agent has not been positiovely identified

Plain Film Appearances

Crohn's disease (also known as granulomatous colitis when confined to the colon) may be indistinguishable from ulcerative colitis when when confined to the colon. The plain film signs of Crohn's disease are as follows:

Abdominal Plain Film Signs	Comment
long gas-filled stricture	can also be seen in other diseases including ulcerative colitis
narrowed small bowel lumen	not seen in ulcerative colitis
small bowel obstruction	indication of marked stenosis causing obstruction
terminal ileum disease	common site for inflammation of bowel in Crohn's disease
skip lesions	Crohn's lesions can be isolated lesions that occur anywhere in the GIT. Multiple islatedarea of inflammation are referred to as skip lesions
bowel wall thickening	sometimes seen in small bowel on plain film
fistula	inflammation affects whole wall tickness nd can lead to breakdowwn of wall and fistula formation
associated with arthropathies	asscociated with sacroiliitis and ankylising spondylitis
cobblestone appearance, particularly of terminal ileum
intra-mural gas	fulminant Crohn's disease can proceed to toxic megacolon with intra-mural gas

Small

Patient's with fulminant Crohn's disease may have daily abdominal radiographs where there is a possibility of toxic megacolon.

Case 1

	The transverse colon is dilated and shows evidence of thumbprinting (black arrow) The descending colon has a thickened featureless wall and pockets of inta-mural gas (white arrow) Patient has known Crohn's disease Appearances consistent with toxic megacolon