IBD Definition• Comprised of two major disorders:Ulcerative Colitis (UC)Crohn’s Disease (CD)
Introduction• Crohn’s Disease is an idiopathic, chronic, transmuralinflammatory process of the bowel that can affectany part of the gastro intestinal tract from the mouthto the anus.• Most cases involve the small bowel, particularly theterminal ileum.
Crohn’s Disease• Crohns disease seems to run in some families. It canoccur in people of all age groups but is most oftendiagnosed in young adults.
Burrill Bernard CrohnBBC(June 13, 1884 – July 29, 1983) was anAmerican gastroenterologistand one of the first to describe the disease forwhich he is known, Crohns diseas .
Prevalence• Higher number of cases of Crohn’s disease found inwestern industrialized nations.• Males and females are equally affected.• Smokers are three times more likely to developCrohns disease.• Crohns disease tends to present initially in the teensand twenties.
Classification of CDOn the area of the gastrointestinal tract which itaffects:• Ileocolic Crohns disease: Affects both the ileumand the large intestine (50%)• Crohns ileitis: Affects the ileum only (30%)• Crohns colitis: Affects the large intestine,accounts for the remaining twenty percent ofcases.
Classification of CDOn the behavior of disease as it progresses:• Stricturing disease causes narrowing of the bowelwhich may lead to bowel obstruction or changes in thecaliber of the feces.Stricturing
Classification of CD• Penetrating disease creates abnormal passage ways betweenthe bowel and other structures such as the skin.• Inflammatory disease causes inflammation without causingstrictures or fistulae.Inflammatory Penetrating
MorphologyCrohn disease may occur in any area of the GItract, but the most common sites involved atpresentation are the terminal ileum,ileocecal valve, and cecum.
Disease is limited to the small intestine alonein about 40% of cases; the small intestineand colon are both involved in 30% ofpatients; and the remainder have onlycolonic involvement.
• The presence of multiple, separate, sharplydelineated areas of disease, resulting in skiplesions, is characteristic of Crohn disease andmay help in the differentiation fromulcerative colitis. Strictures are common.
• The earliest Crohn disease lesion, theaphthous ulcer, may progress, and multiplelesions often coalesce into elongated,serpentine ulcers oriented along the axis ofthe bowel. Edema and loss of the normalmucosal texture are common.
• Sparing of interspersed mucosa, a result ofthe patchy distribution of Crohn disease,results in a coarsely textured, cobblestoneappearance in which diseased tissue isdepressed below the level of normal mucosa
Fissures frequently develop between mucosal foldsand may extend deeply to become fistula tracts orsites of perforation.
The intestinal wall is thickened and rubbery asa consequence of transmural edema,inflammation, submucosal fibrosis, andhypertrophy of the muscularis propria, all ofwhich contribute to stricture formation.
• In cases with extensive transmural disease,mesenteric fat frequently extends around theserosal surface (creeping fat) .
• The microscopic features of active Crohndisease include abundant neutrophils thatinfiltrate and damage crypt epithelium.Clusters of neutrophils within a crypt arereferred to as crypt abscesses andare often associated with crypt destruction.
• Ulceration is common in Crohn disease, andthere may be an abrupt transition betweenulcerated and adjacent normal mucosa. Evenin areas where gross examination suggestsdiffuse disease, microscopic pathology canappear patchy.
• Repeated cycles of crypt destruction andregeneration lead to distortion of mucosalarchitecture; the normally straight andparallel crypts take on bizarre branchingshapes and unusual orientations to oneanother.
• Epithelial metaplasia, another consequence ofchronic relapsing injury, often takes the form ofgastric antral-appearing glands, and is calledpseudopyloric metaplasia. Paneth cellmetaplasia may also occur in the left colon,where Paneth cells are normally absent. Thesearchitectural and metaplastic changes maypersist even when active inflammation hasresolved. Mucosal atrophy, with loss of crypts,may occur after years of disease.
• Noncaseating granulomas, a hallmark of Crohndisease, are found in approximately 35% ofcases and may occur in areas of active diseaseor uninvolved regions in any layer of theintestinal wall. Granulomas may also be presentin mesenteric lymph nodes. Cutaneousgranulomas form nodules that are referred toas metastatic Crohn disease. The absence ofgranulomas does not preclude a diagnosis ofCrohn disease.
Gross pathology of Crohn disease. A, Small-intestinal stricture. B, Linear mucosalulcers and thickened intestinal wall. C, Perforation and associated serositis. D,Creeping fat.
Microscopic pathology of Crohn disease. A, Haphazard crypt organization resultsfrom repeated injury and regeneration. B, Noncaseating granuloma. C, TransmuralCrohn disease with submucosal and serosal granulomas (arrows).
Symptoms• Onset of Crohns disease is between 15-30years of age.• People with Crohns disease will go throughperiods of flare-ups and remission.
Common symptoms of Crohns disease:• abdominal pain• diarrhoea• weight lossLess common symptoms include:• poor appetite• fever, night sweats• rectal pain/rectal bleedingSome patients with Crohns disease also develop symptoms outside ofthe gastrointestinal tract; these symptoms include:• arthritis• skin rash• inflammation of the iris of the eye.Symptoms
Clinical Features• The clinical manifestations of Crohn diseaseare extremely variable. In most patientsdisease begins with intermittent attacks ofrelatively mild diarrhea, fever, andabdominal pain.
• Approximately 20% of patients presentacutely with right lower quadrant pain, fever,and bloody diarrhea that may mimic acuteappendicitis or bowel perforation. Periods ofactive disease are typically interrupted byasymptomatic periods that last for weeks tomany months.
• Disease re-activation can be associated witha variety of external triggers, includingphysical or emotional stress,• specific dietary items, and• cigarette smoking.
• Smocking is a strong exogenous risk factorfor development of Crohn disease and, insome cases, disease onset is associated withinitiation of smoking. Unfortunately, smokingcessation does not result in diseaseremission.
• Iron-deficiency anemia may develop inindividuals with colonic disease, whileextensive small bowel disease may result inserum protein loss and hypoalbuminemia,generalized nutrient malabsorption, ormalabsorption of vitamin B12 and bile salts.Fibrosing strictures, particularly of theterminal ileum, are common and requiresurgical resection.
• Disease often recurs at the site ofanastamosis, and as many as 40% of patientsrequire additional resections within 10 years.Fistulae develop between loops of bowel andmay also involve the urinary bladder, vagina,and abdominal or perianal skin. Perforationsand peritoneal abscesses are common.
Extra-intestinal manifestations ofCrohn diseaseuveitis,migratory polyarthritis,sacroiliitis,ankylosing spondylitis,erythema nodosum, andclubbing of the fingertips, any of which maydevelop before intestinal disease isrecognized.
Pericholangitis and primary sclerosingcholangitis occur in Crohn disease but aremore common in ulcerative colitis. Risk ofcolonic adenocarcinoma is increased inpatients with long-standing colonic disease.
Comparisons of various factors in Crohns disease and ulcerativecolitisCrohns DiseaseCrohns Disease Ulcerative ColitisUlcerative ColitisInvolves terminal ileumInvolves terminal ileum CommonlyCommonly SeldomSeldomInvolves colon?Involves colon?Involves rectum?Involves rectum?UsuallyUsuallySeldomSeldomAlwaysAlwaysUsuallyUsuallyPeri-anal involvementPeri-anal involvement CommonlCommonl SeldomSeldomBile duct involvement?Bile duct involvement? Not associatedNot associated Higher rate of PrimaryHigher rate of Primarysclerosing cholangitissclerosing cholangitisDistribution of DiseaseDistribution of Disease Patchy areas ofPatchy areas ofinflammationinflammationContinuous area ofContinuous area ofinflammationinflammationEndoscopyEndoscopy Linear and serpiginousLinear and serpiginous(snake-like) ulcers(snake-like) ulcersContinuous ulcerContinuous ulcerDepth of inflammationDepth of inflammation May be transmural, deepMay be transmural, deepinto tissuesinto tissuesShallow, mucosalShallow, mucosal
Fistulae, abnormalFistulae, abnormalpassageways betweenpassageways betweenorgansorgansCommonlyCommonly SeldomSeldomBiopsyBiopsy Can have granulomataCan have granulomata Crypt abscesses andCrypt abscesses andcryptitiscryptitisSurgical cure ?Surgical cure ?SmokingSmokingOften returns followingOften returns followingremoval of affectedremoval of affectedpartpartHigher risk for smokersHigher risk for smokersUsually cured byUsually cured byremoval of colon, canremoval of colon, canbe followed bybe followed bypo uchitispo uchitisLower risk for smokersLower risk for smokersAutoimmune diseaseAutoimmune disease Generally regarded asGenerally regarded asan autoimmunean autoimmunediseasediseaseNo consensusNo consensusCancer risk?Cancer risk? Lower than ulcerativeLower than ulcerativecolitiscolitisHigher than CrohnsHigher than CrohnsComparisons of various factors in Crohns disease and UC (Cont.)
Ulcerative Colitis• Ulcerative colitis is a disease that causes ulcers in thelining of the rectum and colon. Ulcers form whereinflammation has killed the cells that usually line thecolon.• Ulcerative colitis can happen at any age, but itusually starts between the ages of 15 and 30. It tendsto run in families.
SymptomsCommon symptoms of ulcerative colitis include:• rectal bleeding and diarrhoea• Variability of symptoms reflects differences in the extent ofdisease (the amount of the colon and rectum that areinflamed) and the intensity of inflammation.• Generally, patients with inflammation confined to the rectumand a short segment of the colon adjacent to the rectum havemilder symptoms and a better prognosis than patients withmore widespread inflammation of the colon.
Ulcerative Colitis• Ulcerative proctitis refers to inflammation that is limited to the rectum. Inmany patients with ulcerative proctitis, mild intermittent rectal bleedingmay be the only symptom. Other patients with more severe rectalinflammation may, in addition, experience rectal pain, urgency (suddenfeeling of having to defecate and a need to rush to the bathroom for fearof soiling), and tenesmus (ineffective, painful urge to move ones bowels).• Proctosigmoiditis involves inflammation of the rectum and the sigmoidcolon (a short segment of the colon contiguous to the rectum). Symptomsof proctosigmoiditis, like that of proctitis, include rectal bleeding, urgency,and tenesmus. Some patients with proctosigmoiditis also develop bloodydiarrhea and cramps.
Ulcerative Colitis• Left-sided colitis involves inflammation that starts at the rectum and extends upthe left colon (sigmoid colon and the descending colon). Symptoms of left-sidedcolitis include bloody diarrhoea, abdominal cramps, weight loss, and left-sidedabdominal pain.• Pancolitis or universal colitis refers to inflammation affecting the entire colon(right colon, left colon, transverse colon and the rectum). Symptoms of pancolitisinclude bloody diarrhoea, abdominal pain and cramps, weight loss, fatigue, fever,and night sweats.• Fulminant colitis is a rare but severe form of pancolitis. Patients with fulminantcolitis are extremely ill with dehydration, severe abdominal pain, protracteddiarrhea with bleeding, and even shock. They are at risk of developing toxicmegacolon (marked dilatation of the colon due to severe inflammation) and colonrupture (perforation).