IBD Flashcards
(19 cards)
Name the two types of IBD
Chrons disease
Ulcerative Colitis
Which class of people does IBD affect?
Teens and people in early 20s
What are the factors leading/causing IBD?
Genetics
Gut microbiota
Defects in gut epithelium
Patients immune system - inappropriate overactivation of mucosal defense mechanisms
Describe how the pathogenesis occurs.
Defects in intestinal epithelial barrier lead to increased uptake of normal luminal bacteria.
Activation of macrophages and dendritic cells occurs; with the production of cytokines and T helper cell activation.
Various genes are implicated e.g. NOD2
Where can Crohn’s Disease occur and where is it most common?
Any part of the GI tract from the mouth to anus
Most commonly occurs in the terminal ileum, ileocecal valve and cecum
What are characteristic features of Chron’s Disease?
Skip lesions - disease occurs in a patchy, intermittent way
Transmural inflammation - inflammation involves all layers of the bowel segment = edematous, thickened, rubbery
With chronicity, fibrosis of the wall leads to stricture formation
Describe the gross morphology of Chron’s Disease.
Deep, linear fissures of “knife-like” ulcers
Appearance of ulcers with islands of uninvolved mucosa in between = cobblestone appearance
Extension of inflammation to serosal surface pulls on the mesenteric fat and makes it extend around the serosal surface = fat wrapping or fat creeping
Describe the microscopic morphology of Crohn’s Disease
All layers - transmural inflammation: infiltrated by mononuclear inflammatory cells
During acute, active inflammation: the mucosal crypts are infiltrated by neutrophils = Crypt Abscesses (also seen in UC)
Often the hallmark of Crohn’s disease is granulomas
Deep narrow fissure ulcers
Inflammatory cells extend into mucosa
Describe the complications of Crohn’s Disease
Malabsorption
Extension of deep ulcer can lead to perforation and abscess formation
Extension through the wall and involvement of adjacent bowel segment can lead to fistula formation (communicating tract between 2 hollow organs)
Opening of an abscess onto the surfaces of the skin leads to sinus formation
Where does ulcerative colitis occur?
Involves the rectum and then spreads proximally to involve the entire colon
Describe the pattern of inflammation of ulcerative colitis.
Colonic involvement is continuous
SI is not usually involved, but mild mucosal inflammation may be found in the terminal ileum = backwash ileitis
Inflammation is limited to the mucosa and superficial submucosa
Describe the morphology associated with UC.
Broad based, shallow ulcers
Islands of regenerating and uninvolved mucosa project into the lumen and look like polyps = pseudopolyps
Crypt abscesses and distortion
List the complications associated with UC.
Inflammatory mediators reach the muscularis propria and inhibit neuromuscular function leading to colonic distension = toxic megacolon
This can perforate and lead to death from septicaemia
Total colectomy is needed
Describe the clinical presentation of IBD.
Intermittent attacks of mild diarrhoea, fever and abdominal pain
Few px have acute onset of abdominal pain and bloody diarrhoea.
Periods of active disease alternate with asymptomatic periods
UC: relapsing attacks of severe abdominal pain and bloody diarrhoea with stringy mucoid material
List the extra-intestinal manifestions of IBD.
Migratory polyarthritis
Uveitis (eye inflammation)
Sacroiliitis (inflammation of sacroiliac joints)
Ankylosing spondylitis (vertebrae fusion)
Erythema nodosum (skin inflammation)
Clubbing of the fingers
Primary sclerosing cholangitis (attacks bile ducts)
What is the most serious complication of ulcerative colitis and colonic Crohn’s disease?
Dysplasia and malignancy
What is the risk of dysplasia and malignancy related to?
Duration of disease (10+ years)
Extent of gut involvement
Greater frequency of acute exacerbations
What methods are used to detect dysplasia?
Colonoscopy and biopsies
What is mucosal dysplasia a precursor lesion for?
Precursor lesion of colonic adenocarcinoma
