Editing Ulcerative colitis (section)

===Gastrointestinal===
People with ulcerative colitis usually present with [[diarrhea]] mixed with [[blood]],<ref name=Ungaro /> of gradual onset that persists for an extended period of time (weeks). It is estimated that 90% of people experience rectal bleeding (of varying severity), 90% experience watery or loose stools with increased stool frequency (diarrhea), and 75-90% of people experience bowel urgency.<ref name="Gros 2023" /> Additional symptoms may include fecal incontinence, mucous rectal discharge, and nocturnal defecations.<ref name=Ungaro /> With [[proctitis]] (inflammation of the rectum), people with UC may experience urgency or [[rectal tenesmus]], which is the urgent desire to evacuate the bowels but with the passage of little stool.<ref name=Ungaro /> Tenesmus may be misinterpreted as [[constipation]], due to the urge to defecate despite small volume of stool passage. Bloody diarrhea and abdominal pain may be more prominent features in severe disease.<ref name=Ungaro /> The severity of abdominal pain with UC varies from mild discomfort to very painful bowel movements and abdominal cramping.<ref name=":1">{{cite journal | vauthors = Magro F, Gionchetti P, Eliakim R, Ardizzone S, Armuzzi A, Barreiro-de Acosta M, Burisch J, Gecse KB, Hart AL, Hindryckx P, Langner C, Limdi JK, Pellino G, Zagórowicz E, Raine T, Harbord M, Rieder F | title = Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 1: Definitions, Diagnosis, Extra-intestinal Manifestations, Pregnancy, Cancer Surveillance, Surgery, and Ileo-anal Pouch Disorders | journal = Journal of Crohn's & Colitis | volume = 11 | issue = 6 | pages = 649–670 | date = June 2017 | pmid = 28158501 | doi = 10.1093/ecco-jcc/jjx008 | doi-access = free }}</ref> High frequency of bowel movements, weight loss, nausea, fatigue, and fever are also common during disease flares. Chronic bleeding from the GI tract, chronic inflammation, and iron deficiency often leads to [[anemia]], which can affect quality of life.<ref name=Kaitha>{{cite journal | vauthors = Kaitha S, Bashir M, Ali T | title = Iron deficiency anemia in inflammatory bowel disease | journal = World Journal of Gastrointestinal Pathophysiology | volume = 6 | issue = 3 | pages = 62–72 | date = August 2015 | pmid = 26301120 | pmc = 4540708 | doi = 10.4291/wjgp.v6.i3.62 | doi-access = free }}</ref>

The clinical presentation of ulcerative colitis depends on the extent of the disease process.<ref name=Hanauer>{{cite journal | vauthors = Hanauer SB | title = Inflammatory bowel disease | journal = The New England Journal of Medicine | volume = 334 | issue = 13 | pages = 841–848 | date = March 1996 | pmid = 8596552 | doi = 10.1056/NEJM199603283341307 }}</ref> Up to 15% of individuals may have severe disease upon initial onset of symptoms.<ref name=Ungaro /> A substantial proportion (up to 45%) of people with a history of UC without any ongoing symptoms (clinical remission) have objective evidence of ongoing inflammation.<ref>{{cite journal | vauthors = Rosenberg L, Lawlor GO, Zenlea T, Goldsmith JD, Gifford A, Falchuk KR, Wolf JL, Cheifetz AS, Robson SC, Moss AC | title = Predictors of endoscopic inflammation in patients with ulcerative colitis in clinical remission | journal = Inflammatory Bowel Diseases | volume = 19 | issue = 4 | pages = 779–784 | date = 2013 | pmid = 23446338 | pmc = 3749843 | doi = 10.1097/MIB.0b013e3182802b0e | doi-access = free }}</ref> Ulcerative colitis is associated with a generalized inflammatory process that can affect many parts of the body. Sometimes, these associated extra-intestinal symptoms are the initial signs of the disease.<ref name=Colìa>{{cite journal | vauthors = Colìa R, Corrado A, Cantatore FP | title = Rheumatologic and extraintestinal manifestations of inflammatory bowel diseases | journal = Annals of Medicine | volume = 48 | issue = 8 | pages = 577–585 | date = December 2016 | pmid = 27310096 | doi = 10.1080/07853890.2016.1195011 | s2cid = 1796160 }}</ref>

====Extent of involvement====
[[File:Classification of Colitis.jpg|thumb|Classification of colitis, often used in defining the extent of involvement of ulcerative colitis, with proctitis (blue), proctosigmoiditis (yellow), left sided colitis (orange) and pancolitis (red). All classes extend distally to the end of the rectum.]]
[[File:Severe ulcerative colitis.jpg|thumb|Gross pathology of normal colon (left) and severe ulcerative colitis (right), forming pseudopolyps (smaller than the cobblestoning typically seen in Crohn's disease), over a continuous area (rather than skip lesions of Crohn's disease), and with a relatively gradual transition from normal colon (while Crohn's is typically more abrupt).]]
In contrast to Crohn's disease, which can affect areas of the gastrointestinal tract outside of the colon, ulcerative colitis is usually confined to the colon. Inflammation in ulcerative colitis is usually continuous, typically involving the rectum, with involvement extending proximally (to [[sigmoid colon]], ascending colon, etc.).<ref name=ACG_Guidelines_2019 /> In contrast, inflammation with Crohn's disease is often patchy, with so-called "skip lesions" (intermittent regions of inflamed bowel).<ref name="Feuerstein_Crohns">{{cite journal | vauthors = Feuerstein JD, Cheifetz AS | title = Crohn Disease: Epidemiology, Diagnosis, and Management | journal = Mayo Clinic Proceedings | volume = 92 | issue = 7 | pages = 1088–1103 | date = July 2017 | pmid = 28601423 | doi = 10.1016/j.mayocp.2017.04.010 | s2cid = 20223406 | doi-access = free }}</ref>

The disease is classified by the extent of involvement, depending on how far the disease extends:<ref name=":1" /> [[proctitis]] (rectal inflammation), left sided colitis (inflammation extending to descending colon), and extensive colitis (inflammation proximal to the descending colon).<ref name=ACG_Guidelines_2019 /> Proctosigmoiditis describes inflammation of the rectum and sigmoid colon. Pancolitis describes involvement of the entire colon, extending from the rectum to the cecum. While usually associated with Crohn's disease, [[ileitis]] (inflammation of the ileum) also occurs in UC. About 17% of individuals with UC have ileitis.<ref>{{cite journal | vauthors = Haskell H, Andrews CW, Reddy SI, Dendrinos K, Farraye FA, Stucchi AF, Becker JM, Odze RD | title = Pathologic features and clinical significance of "backwash" ileitis in ulcerative colitis | journal = The American Journal of Surgical Pathology | volume = 29 | issue = 11 | pages = 1472–1481 | date = November 2005 | pmid = 16224214 | doi = 10.1097/01.pas.0000176435.19197.88 | s2cid = 42108108 }}</ref> Ileitis more commonly occurs in the setting of pancolitis (occurring in 20% of cases of pancolitis),<ref name=Ungaro /> and tends to correlate with the activity of colitis. This so-called "backwash ileitis" can occur in 10–20% of people with [[pancolitis]] and is believed to be of little clinical significance.<ref name="ISBN 0071599916">Fauci ''et al.'' ''Harrison's Internal Medicine'', 17th ed. New York: McGraw-Hill Medical, 2008. {{ISBN|978-0-07-159991-7}}</ref>

====Severity of disease====
In addition to the extent of involvement, UC is also characterized by severity of disease.<ref name=ACG_Guidelines_2019 /> Severity of disease is defined by symptoms, objective markers of inflammation (endoscopic findings, blood tests), disease course, and the impact of the disease on day-to-day life.<ref name=ACG_Guidelines_2019 /> Most patients are categorized through endoscopy and fecal calprotectin levels. Indicators of low risk for future complications in mild and moderate UC include the following parameters: exhibiting less than 6 stools daily and lack of fever/weight loss. Other indicators include lack of extraintestinal symptoms, low levels of the inflammatory markers [[C-reactive protein]] (CRP), and [[erythrocyte sedimentation rate]] (ESR), and fecal [[calprotectin]], and later age of diagnosis (over 40 years).<ref name=":2">{{cite web |title=UpToDate |url=https://www.uptodate.com/contents/medical-management-of-low-risk-adult-patients-with-mild-to-moderate-ulcerative-colitis?search=ulcerative%20colitis&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2 |access-date=8 November 2022 |website=www.uptodate.com}}</ref> Mild disease correlates with fewer than four stools daily; in addition, mild urgency and rectal bleeding may occur intermittently.<ref name=ACG_Guidelines_2019 />  Mild disease lacks [[Systemic disease|systemic]] signs of toxicity (e.g. fever, chills, weight changes) and exhibits normal levels of the serum inflammatory markers ESR and CRP.<ref name=":2" />

Moderate to severe disease correlates with more than six stools daily, frequent bloody stools and urgency.<ref name=ACG_Guidelines_2019 /> Moderate abdominal pain, low-grade [[fever]], {{convert|38|to|39|C|F}}, and anemia may develop.<ref name=ACG_Guidelines_2019 /> ESR and CRP are usually elevated.<ref name=ACG_Guidelines_2019 />

The Mayo Score, which incorporates a combination of clinical symptoms (stool frequency and amount of rectal bleeding) with endoscopic findings and a physicians assessment of severity, is often used clinically to classify UC as mild, moderate or severe.<ref name="Gros 2023" />

Acute-Severe Ulcerative Colitis (ASUC) is a severe form which presents acutely and with severe symptoms. This fulminant type is associated with severe symptoms (usually diarrhea, rectal bleeding and abdominal pain) and is usually associated with systemic symptoms including fever.<ref name="Gros 2023" /> It is associated with a high mortality rate as compared to milder forms of UC, with a 3-month and 12 month mortality rate of 0.84% and 1% respectively.<ref name="Gros 2023" /> People with fulminant UC may have inflammation extending beyond just the mucosal layer, causing impaired colonic motility and leading to [[toxic megacolon]]. Toxic megacolon represents a medical emergency, one often treated surgically. If the [[serous membrane]] is involved, a colonic [[gastrointestinal perforation|perforation]] may ensue, which has a 50% mortality rate in people with UC.<ref>{{cite web |title=UpToDate |url=https://www.uptodate.com/contents/clinical-manifestations-diagnosis-and-prognosis-of-ulcerative-colitis-in-adults?search=clinical%20manifestation%20of%20ulcerative%20colitis&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1 |access-date=9 November 2022 |website=www.uptodate.com}}</ref> Other complications include [[hemorrhage]], [[venous thromboembolism]], and secondary infections of the colon including ''[[C. difficile]]'' or [[cytomegalovirus]] colitis.<ref name="Gros 2023" />

Ulcerative colitis may improve and enter remission.<ref name=ACG_Guidelines_2019 />