Editing Appendicitis (section)

==Causes==
[[File:Stomach colon rectum diagram-en.svg|thumb|Location of the appendix in the [[digestive system]]]]
[[File:3D still showing appendicitis.jpg|alt=3D still showing appendicitis.|thumb|3D model of appendicitis.]]
Acute appendicitis seems to be the result of a primary obstruction of the [[Appendix (anatomy)|appendix]].<ref name=Wang1937>{{Cite journal|vauthors=[[Owen Harding Wangensteen|Wangensteen OH]], Bowers WF |title=Significance of the obstructive factor in the genesis of acute appendicitis |journal=Archives of Surgery |volume=34 |issue= 3|pages=496–526 |year=1937|doi=10.1001/archsurg.1937.01190090121006}}</ref><ref name=Piep1982/> Once this obstruction occurs, the appendix becomes filled with [[mucus]] and swells. This continued production of mucus leads to increased pressures within the lumen and the walls of the appendix. The increased pressure results in [[thrombosis]] and [[Vascular occlusion|occlusion]] of the small vessels, and stasis of [[Lymphatic system|lymphatic flow]]. At this point, spontaneous recovery rarely occurs. As the occlusion of blood vessels progresses, the appendix becomes [[Ischemia|ischemic]] and then [[Necrosis|necrotic]]. As [[bacteria]] begin to leak out through the dying walls, [[pus]] forms within and around the appendix (suppuration). The result is appendiceal rupture (a 'burst appendix') causing [[peritonitis]], which may lead to [[sepsis]] and in rare cases, [[death]]. These events are responsible for the slowly evolving abdominal pain and other commonly associated symptoms.<ref name=Schw2010/>

The causative agents include [[bezoar]]s, foreign bodies, [[physical trauma|trauma]],<ref>{{Cite journal |last=Fowler |first=Royal H. |date=April 1938 |title=The Rare Incidence of Acute Appendicitis Resulting from External Trauma |journal=Annals of Surgery |volume=107 |issue=4 |pages=529–539 |doi=10.1097/00000658-193804000-00007 |issn=0003-4932 |pmc=1386836 |pmid=17857157}}</ref><ref>{{Cite journal |last1=Toumi |first1=Zaher |last2=Chan |first2=Anthony |last3=Hadfield |first3=Matthew B. |last4=Hulton |first4=Neil R. |date=September 2010 |title=Systematic review of blunt abdominal trauma as a cause of acute appendicitis |journal=Annals of the Royal College of Surgeons of England |volume=92 |issue=6 |pages=477–482 |doi=10.1308/003588410X12664192075936 |issn=1478-7083 |pmc=3182788 |pmid=20513274}}</ref> [[Lymphadenopathy|lymphadenitis]] and, most commonly, calcified fecal deposits that are known as [[appendicolith]]s or [[fecalith]]s.<ref>{{cite journal | last1= Hollerman |first1=J. |last2=Bernstein |first2=MA |last3=Kottamasu |first3=SR |last4=Sirr |first4=SA | year = 1988 | title = Acute recurrent appendicitis with appendicolith | journal =The American Journal of Emergency Medicine | volume = 6 | issue = 6| pages = 614–617 | doi=10.1016/0735-6757(88)90105-2|pmid=3052484 }}</ref><ref name=":0" /> The occurrence of [[Fecaloma|obstructing fecalith]]s has attracted attention since their presence in people with appendicitis is higher in developed than in developing countries.<ref>{{cite journal | vauthors = Jones BA, Demetriades D, Segal I, Burkitt DP | title = The prevalence of appendiceal fecaliths in patients with and without appendicitis. A comparative study from Canada and South Africa | journal = Annals of Surgery | volume = 202 | issue = 1 | pages = 80–82 | date = July 1985 | pmid = 2990360 | pmc = 1250841 | doi = 10.1097/00000658-198507000-00013 }}</ref> In addition, an appendiceal fecalith is commonly associated with complicated appendicitis.<ref>{{cite journal | vauthors = Nitecki S, Karmeli R, Sarr MG | title = Appendiceal calculi and fecaliths as indications for appendectomy | journal = Surgery, Gynecology & Obstetrics | volume = 171 | issue = 3 | pages = 185–188 | date = September 1990 | pmid = 2385810 }}</ref> Fecal stasis and arrest may play a role, as demonstrated by people with acute appendicitis having fewer bowel movements per week compared with healthy controls.<ref name=":0">{{cite journal | vauthors = Dehghan A, Moaddab AH, Mozafarpour S | title = An unusual localization of trichobezoar in the appendix | journal = The Turkish Journal of Gastroenterology | volume = 22 | issue = 3 | pages = 357–358 | date = June 2011 | pmid = 21805435 | doi = 10.4318/tjg.2011.0232 }}</ref><ref>{{cite journal | vauthors = Arnbjörnsson E | title = Acute appendicitis related to faecal stasis | journal = Annales Chirurgiae et Gynaecologiae | volume = 74 | issue = 2 | pages = 90–93 | year = 1985 | pmid = 2992354 }}</ref>

The occurrence of a fecalith in the appendix was thought to be attributed to a right-sided fecal retention reservoir in the colon and a prolonged transit time. However, a prolonged transit time was not observed in subsequent studies.<ref>{{cite journal | vauthors = Raahave D, Christensen E, Moeller H, Kirkeby LT, Loud FB, Knudsen LL | title = Origin of acute appendicitis: fecal retention in colonic reservoirs: a case-control study | journal = Surgical Infections | volume = 8 | issue = 1 | pages = 55–62 | date = February 2007 | pmid = 17381397 | doi = 10.1089/sur.2005.04250 }}</ref> [[Diverticular disease]] and [[adenomatous polyps]] were historically unknown and [[colon cancer]] was exceedingly rare in communities where appendicitis itself was rare or absent, such as various African communities. Studies have implicated a transition to a [[Western diet]] lower in [[Dietary fiber|fiber]] in rising frequencies of appendicitis as well as the other aforementioned colonic diseases in these communities.<ref>{{cite journal | vauthors = Burkitt DP | title = The aetiology of appendicitis | journal = The British Journal of Surgery | volume = 58 | issue = 9 | pages = 695–699 | date = September 1971 | pmid = 4937032 | doi = 10.1002/bjs.1800580916 | pmc = 1598350 }}</ref><ref>{{cite journal | vauthors = Segal I, Walker AR | title = Diverticular disease in urban Africans in South Africa | journal = Digestion | volume = 24 | issue = 1 | pages = 42–46 | year = 1982 | pmid = 6813167 | doi = 10.1159/000198773 }}</ref> And acute appendicitis has been shown to occur antecedent to cancer in the colon and rectum.<ref>{{cite journal | vauthors = Arnbjörnsson E | title = Acute appendicitis as a sign of a colorectal carcinoma | journal = Journal of Surgical Oncology | volume = 20 | issue = 1 | pages = 17–20 | date = May 1982 | pmid = 7078180 | doi = 10.1002/jso.2930200105 | s2cid = 30187238 }}</ref> Several studies offer evidence that a low fiber intake is involved in the pathogenesis of appendicitis.<ref>{{cite journal | vauthors = Burkitt DP, Walker AR, Painter NS | title = Effect of dietary fibre on stools and the transit-times, and its role in the causation of disease | journal = Lancet | volume = 2 | issue = 7792 | pages = 1408–1412 | date = December 1972 | pmid = 4118696 | doi = 10.1016/S0140-6736(72)92974-1 }}</ref><ref>{{cite journal | vauthors = Adamidis D, Roma-Giannikou E, Karamolegou K, Tselalidou E, Constantopoulos A | title = Fiber intake and childhood appendicitis | journal = International Journal of Food Sciences and Nutrition | volume = 51 | issue = 3 | pages = 153–157 | date = May 2000 | pmid = 10945110 | doi = 10.1080/09637480050029647 | s2cid = 218989618 }}</ref><ref>{{cite journal | vauthors = Hugh TB, Hugh TJ | title = Appendicectomy – becoming a rare event? | journal = The Medical Journal of Australia | volume = 175 | issue = 1 | pages = 7–8 | date = July 2001 | doi = 10.5694/j.1326-5377.2001.tb143501.x | pmid = 11476215 | s2cid = 33795090 | url = http://www.mja.com.au/public/issues/175_01_020701/hugh/hugh.html | url-status = live | archive-url = https://web.archive.org/web/20060826042124/http://www.mja.com.au/public/issues/175_01_020701/hugh/hugh.html | archive-date = 2006-08-26 }}</ref> This low intake of dietary fiber is in accordance with the occurrence of a right-sided fecal reservoir and the fact that dietary fiber reduces transit time.<ref>{{cite journal | vauthors = Gear JS, Brodribb AJ, Ware A, Mann JI | title = Fibre and bowel transit times | journal = The British Journal of Nutrition | volume = 45 | issue = 1 | pages = 77–82 | date = January 1981 | pmid = 6258626 | doi = 10.1079/BJN19810078 | doi-access = free }}</ref>