inflammatory bowel disease Flashcards
what is the distinction between ulcerative colitis and Crohn’s disease?
UC involves colon
Crohns affects any part of the GI tract from mouth to anus
what are the clinical comparisons between ulcerative colitis and Crohn’s disease?
UC more common in non smokers whereas Crohn’s more common in smokers
presentation of UC is bloody diarrhoea, Crohn’s is variable with pain, diarrhoea, weight loss
histology of UC: inflammation limited to mucosa, Crohns affects submucosal or transmural inflammation, deep fissuring ulcers
colectomy of UC is curative whereas for Crohn’s it isnt
what is the pathophysiology of IBD?
abnormal host response to environmental trigger in genetically susceptible individuals
causes inflammation of the intestine and release of inflammatory mediators such as TNF, IL-12, IL-23 causing tissue damage
both diseases, intestinal wall infiltrated with acute and chronic inflammatory cells
what is the pathophysiology of ulcerative colitis?
inflammation involves rectum but can spread to involve sigmoid colon or whole colon
inflammation confluent and more severe distally
inflammation limited to mucosa and spares deeper layers of bowel wall
both acute and chronic inflammatory cells infiltrate lamina propria and crypts : crypt abscesses typical
dysplasia: HEAPING OF CELLS within crypts, nuclear atypia and increased mitotic rate herald development of colon cancer
what is the pathophysiology of Crohn’s disease?
sites most commonly infected in order: terminal ileum, ileum, jejunum
entire wall of bowel is oedematous and thickened
deep ulcers which often appear as linear fissures - mucosa between them described as cobblestone
these could penetrate the bowel wall to initiate abscesses or fistulas involving bowel, bladder, uterus, vagina and skin of perineum
patchy distribution, inflammatory process interrupted by islands of normal mucosa
what are the clinical features of UC?
major symptom is bloody diarrhoea
first attack most severe and thereafter disease is followed by relapses and remissions
frequent, small volume fluid stools whereas some constipated and pass pellety stools
what could provoke a relapse in UC?
emotional stress, intercurrent infection, gastroenteritis, antibiotics, NSAID therapy
what are the clinical features of Crohn’s disease?
major symptoms are abdominal pain, diarrhoea and weight loss
ileal Crohns disease may cause subacute or even acute intestinal obstruction
pain often associated with diarrhoea usually watery and does not contain blood or mucus
almost all patients lose weight as they avoid food since eating provokes pain
abdominal tenderness most marked over inflamed area
diagnosis basis of imaging and clinical presentation
why does weight loss happen in Crohns disease?
malabsorption- present with features of fat, protein or vitamin deficiencies
what conditions can mimic ulcerative or crohn’s colitis?
infective: bacterial, viral or protozoal
non-infective: vascular, NSAIDS, neoplastic, diverticulitis, colonic carcinoma, collagenous colitis, ischaemic colitis
in general, diarrhoea lasting longer than 10 days in western world unlikely to be due to infection
what are the complications of IBD?
life - threatening colonic inflammation
haemorrhage
fistulas
cancer
extraintestinal
what happens in life threatening colonic inflammation?
extreme cases, colon dilates (toxic megacolon) and bacterial toxins pass freely across diseased mucosa into portal then systemic circulation
most commonly in first attack of colitis
abdominal x ray taken daily, when transverse colon dilated to more than 6cm, high risk of colonic perforation
what is a fistula, which condition is it specific to?
Crohn’s disease
what investigations should be performed?
bacteriology: exclude infection
endoscopy : sigmoidscopy with biopsy is essential investigation in all patients who present with diarrhoea
what are the key aims of the management of IBD?
treat acute attacks
prevent relapses
detect carcinoma at an early stage
select patients for surgery
multidiscipliary team
