Difference between revisions of "Colon"

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Revision as of 20:14, 8 July 2010

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move IBD to inflammatory bowel disease article
m (move IBD to inflammatory bowel disease article)
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**HIV/AIDS.
**HIV/AIDS.


==Inflammatory bowel disease (IBD)==
==Inflammatory bowel disease==
Exists in two main flavours:
{{main|Inflammatory bowel disease}}
*Crohn's disease (CD).
*Ulcerative colitis (UC).


===Clinical===
The bread 'n butter of gastroenterology. A detailed discussion of '''IBD''' is in the ''[[inflammatory bowel disease]]'' article.
*It is important to differentiate UC and CD as the management is different.  
*UC patients get pouches... CD patients do not.
 
Epidemiology:
*NOD2/CARD15 variants are assoc. with stricturing CD, early need for surgery and recurrence.<ref name=pmid16244543 >{{cite journal |author=Alvarez-Lobos M, Arostegui JI, Sans M, ''et al.'' |title=Crohn's disease patients carrying Nod2/CARD15 gene variants have an increased and early need for first surgery due to stricturing disease and higher rate of surgical recurrence |journal=Ann. Surg. |volume=242 |issue=5 |pages=693–700 |year=2005 |month=November |pmid=16244543 |pmc=1409853 |doi= |url=}}</ref>


===Microscopic===
===Microscopic===
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**Paneth cells should ''not'' be in the left colon<ref name=pmid11851832>{{cite journal |author=Tanaka M, Saito H, Kusumi T, ''et al'' |title=Spatial distribution and histogenesis of colorectal Paneth cell metaplasia in idiopathic inflammatory bowel disease |journal=J. Gastroenterol. Hepatol. |volume=16 |issue=12 |pages=1353–9 |year=2001 |month=December |pmid=11851832 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0815-9319&date=2001&volume=16&issue=12&spage=1353}}</ref> - if you see 'em think of IBD and other long-standing injurious processes.
**Paneth cells should ''not'' be in the left colon<ref name=pmid11851832>{{cite journal |author=Tanaka M, Saito H, Kusumi T, ''et al'' |title=Spatial distribution and histogenesis of colorectal Paneth cell metaplasia in idiopathic inflammatory bowel disease |journal=J. Gastroenterol. Hepatol. |volume=16 |issue=12 |pages=1353–9 |year=2001 |month=December |pmid=11851832 |doi= |url=http://www3.interscience.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0815-9319&date=2001&volume=16&issue=12&spage=1353}}</ref> - if you see 'em think of IBD and other long-standing injurious processes.
**Some claim that (friendly right colonic) paneth cells and paneth cell metaplasia look quite different and can be distinguished.<ref name=pmid12655793>{{cite journal |author=Rubio CA, Nesi G |title=A simple method to demonstrate normal and metaplastic Paneth cells in tissue sections |journal=In Vivo |volume=17 |issue=1 |pages=67–71 |year=2003 |pmid=12655793 |doi= |url=}}</ref>
**Some claim that (friendly right colonic) paneth cells and paneth cell metaplasia look quite different and can be distinguished.<ref name=pmid12655793>{{cite journal |author=Rubio CA, Nesi G |title=A simple method to demonstrate normal and metaplastic Paneth cells in tissue sections |journal=In Vivo |volume=17 |issue=1 |pages=67–71 |year=2003 |pmid=12655793 |doi= |url=}}</ref>
Notes:
# Microscopic features can be remembered by [[mnemonic]] ''CPP'': Crypts (abnormal), Plasmacytosis, Paneth cells where they don't belong.
# If you see architectural distortion (e.g. crypt branching) in the left colon, look for Paneth cells.
# The hepatic flexure is considered the divider for normal paneth cells and abnormal paneth cells, i.e. paneth cells proximal to the hepatic flexure are normal; paneth cells distal to the hepatic flexure are abnormal.<ref>STC. 14 December 2009.</ref>
===Crohn's disease vs. ulcerative colitis===
UC features:<ref name=Ref_PBoD850>{{Ref PBoD|850}}</ref>
*Mucosal involvement --sometimes submucosa.
*No skip lesions.
*Colon/rectum only.
** UC may have 'ileal backwash' -- mild ileal inflammation due to backwash of inflammatory soup from colon.
*"No granulomas".
**Superficial granulomas in the mucosa are non-specific, especially if they are beside an inflammed crypt, i.e. they may be present in UC.<ref name=pmid12147095>{{Cite journal  | last1 = Shepherd | first1 = NA. | title = Granulomas in the diagnosis of intestinal Crohn's disease: a myth exploded? | journal = Histopathology | volume = 41 | issue = 2 | pages = 166-8 | month = Aug | year = 2002 | doi =  | PMID = 12147095 }}</ref><ref name=pmid12121237>{{Cite journal  | last1 = Mahadeva | first1 = U. | last2 = Martin | first2 = JP. | last3 = Patel | first3 = NK. | last4 = Price | first4 = AB. | title = Granulomatous ulcerative colitis: a re-appraisal of the mucosal granuloma in the distinction of Crohn's disease from ulcerative colitis. | journal = Histopathology | volume = 41 | issue = 1 | pages = 50-5 | month = Jul | year = 2002 | doi =  | PMID = 12121237 }}</ref>
***Deep granulomas are specific for Crohn's disease.
Example of a superficial granuloma that is non-specific, i.e. this could be UC or CD:
*[http://commons.wikimedia.org/wiki/File:Colitis_with_granuloma_low_mag.jpg Colitis with a superficial granuloma (wikimedia.org)].
==Ulcerative colitis==
===General===
*Often abbreviated as ''UC''.
===Epidemiology===
*Associated with ''[[sclerosing cholangitis]]''.
*Appendicitis is considered protective against UC.<ref name=pmid19685454>{{Cite journal  | last1 = Beaugerie | first1 = L. | last2 = Sokol | first2 = H. | title = Appendicitis, not appendectomy, is protective against ulcerative colitis, both in the general population and first-degree relatives of patients with IBD. | journal = Inflamm Bowel Dis | volume =  | issue =  | pages =  | month = Aug | year = 2009 | doi = 10.1002/ibd.21064 | PMID = 19685454 }}</ref><ref name=pmid19273505>{{Cite journal  | last1 = Timmer | first1 = A. | last2 = Obermeier | first2 = F. | title = Reduced risk of ulcerative colitis after appendicectomy. | journal = BMJ | volume = 338 | issue =  | pages = b225 | month =  | year = 2009 | doi =  | PMID = 19273505 }}</ref>
*Smoking is protective; the opposite is true for Crohn's disease.<ref name=pmid19273505/>
===Gross===
*Conventionally considered to be contiguous, i.e. no "skip lesions", with rectal involvement being most severe.
*Dependent on the study one reads... rectal sparing may be seen in 15% of UC patients.<ref>{{cite journal |author=Bernstein CN, Shanahan F, Anton PA, Weinstein WM |title=Patchiness of mucosal inflammation in treated ulcerative colitis: a prospective study |journal=Gastrointest. Endosc. |volume=42 |issue=3 |pages=232-7 |year=1995 |month=September |pmid=7498688 |doi= |url=}}</ref>
===Microscopic===
*Lack of granulomas.
*No full wall-thickness inflammation.
==Crohn's disease==
===General===
*Often abbreviated as ''CD''.
===Gross===
*Transmural inflammation, i.e. full thickness of bowel wall.
*Creeping fat.
*Cobblestone appearance -- may be described as such on endoscopy.
*Serpiginous ulcers.
** Image: [http://en.wikipedia.org/wiki/File:CD_serpiginous_ulcer.jpg Serpiginous ulcer (endoscopy) - wikipedia.org].
===Microscopic===
Features:<ref name=pmid10048734/>
*Segmental crypt architectural abnormalities,
*Mucin depletion,
*Mucin preservation at the active sites, and
*Focal chronic inflammation without crypt atrophy.


==Bowel ischemia==
==Bowel ischemia==
Michael
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