Inflammatory bowel disease Flashcards
How common is IBD?
In the West, the incidence of ulcerative colitis is stable at 10–20 per 100 000, with a prevalence of 100–200 per 100 000, while the incidence of Crohn’s disease is increasing and is now 5–10 per 100 000, with a prevalence of 50–100 per 100 000.
Who is affected by IBD?
UC - M=F, any ethnic group
CD - M
What causes IBD?
- Has both environmental and genetic components
- Genetic variants that predispose to Crohn’s disease may have undergone positive selection by protecting against infectious diseases, including tuberculosis.
- It is thought that IBD develops because these genetically susceptible individuals mount an abnormal inflammatory response to environmental triggers, such as intestinal bacteria.
- This leads to inflammation of the intestine with release of inflammatory mediators, including TNF, IL-12 and IL-23, which cause tissue damage.
- In both diseases, the intestinal wall is infiltrated with acute and chronic inflammatory cells but there are important differences between the conditions in the distribution of lesions and in histological features.
What are the risk factors for UC?
- non-smoker or ex-smoker status
- commensal gut bacteria dysbiosis
- ?breastfeeding exposure
- ?dietary fibre
- ?Abx exposure
What are the risk factors for CD?
- smoker status
- commensal gut bacteria dysbiosis
- Western diet (low residue, high sugar)
- ?breastfeeding exposure
- ?dietary fibre
- ?Abx exposure
What is the presentation of UC?
- Rectal bleeding with passage of mucous and bloody diarrhoea
- Extra-intestinal manifestations
What is the presentation of CD?
- Diarrhoea
- Abdominal pain
- Weight loss
- Constitutional symptoms (malaise, lethargy, anorexia, nausea, vomiting, low fever)
- Some patients may have no GI symptoms
- Symptoms depend on segment of bowel affected e.g. bloody diarrhoea in colonic disease and seatorrhoea in small bowel disease
What are the musculoskeletal extra-intestinal manifestations of IBD?
- seronegative spondyloarthropaties
- peripheral arthritis
- axial arthopathies (sacroiliitis, ankylosing spondylitis)
What are the dermatological extra-intestinal manifestations of IBD?
- erythema nodosum
- pyoderma gangrenosum
- apthous stomatitis
What are the ocular extra-intestinal manifestations of IBD?
- episcleritis
- scleritis
- uveitis
What are the hepatobiliary extra-intestinal manifestations of IBD?
- sclerosing cholangitis
- fatty liver
- chronic hepatitis
- cirrhosis
- gallstones
What are the signs of UC on examination?
- Generally no specific signs
- Abdominal distention and/or temderness
- Tachycardia and pyrexia (in severe colitis)
- PR will usually show blood
- Ridgid sigmoidoscopy is usually abnormal, showing inflamed, bleeding and friable mucosa
What are the signs of CD on examination?
- Weight loss
- Signs of malnutrition
- Aphthous ulceration of the mouth
- Abdominal tenderness and/or right iliac fossa mass
What are the differential diagnoses for IBD?
Anorexia Nervosa Appendicitis Bacterial Gastroenteritis Bulimia Nervosa Celiac Disease (Sprue) Clostridium Difficile Colitis Collagenous and Lymphocytic Colitis Colorectal malignancy Cytomegalovirus (CMV) Cytomegalovirus Colitis Diverticulitis Eosinophilic Gastroenteritis Food Poisoning Giardiasis Intestinal Motility Disorders Intestinal Radiation Injury Irritable Bowel Syndrome Lactose Intolerance Salmonella Infection (Salmonellosis) Viral Gastroenteritis
What are the ano/perianal complications of CD?
Fissure in ano Haemorrhoids Skin tags Perianal abcess Ischiorectal abcess Fistula in ano Anorectal fistulae
