Inflammatory bowel disease Flashcards
What is Crohn’s disease?
Disorder of unknown aetiology characterised by transmural inflammation of the GIT.
Where does Crohn’s disease usually affect?
May involve any part of the entire GIT: mouth –> perianal. Usually seen in terminal ileal and perianal locations.
What is Crohn’s disease characterised by?
-Skip lesions (normal bowel mucosa found between diseased areas).
What are the complications of Crohn’s disease?
- Transmural inflammation –> fibrosis –> intestinal obstruction
- Inflammation –> sinus tracts –> penetration of serosa –> perforations and fistulae.
- Malnutrition (damaged mucosa, poor absorption).
Where is the incidence of Crohn’s disease highest?
Highest incidence in northern climates and developed countries; lowest in southern climates and less developed countries.
When is the peak age of onset of CD?
15 - 40 years.
Smaller second peak 60 - 80 years.
Are women or men more affected by CD?
Equally affected.
What is the aetiology of Crohn’s disease?
Unclear: genetic, environmental factors + host immune response.
How does the initial CD lesion begin?
Inflammatory infiltrate around intestinal crypts–> ulceration of the superficial mucosa. Inflammation progresses to involve deeper layers and forms non-caseating granulomas. Granulomas involve all layers of intestinal wall, mesentery and regional lymph nodes.
What are the early endoscopic findings of CD?
Hyperaemia and oedema of inflammed mucosa. Progresses to discrete superficial ulcers separated by healthy tissue (skip lesions).
Why are individuals with CD prone to oxalate kidney stone formation?
CD involving terminal ileum interferes with bile acid resorption –> steatorrhoea –> excessive fat in stool binds calcium increasing oxalate absorption.
What are the extra intestinal manifestations of CD?
Skin, joints, mouth, eyes, liver and bile ducts.
How is CD classified?
Vienna classification:
1) Age at Diagnosis (A1, A2)
2) Location (L1-4)
3) Behaviour (B1- B3)
CD secondary prevention?
Smoking cessation only lifestyle modification shown to effect recurrence.
-CRC screening colonoscopy every 1-2y, 8y post diagnosis.
What are the key diagnostic factors for CD?
-Presence of RFx
-Abdo pain
-Prolonged diarrhoea
-Perianal lesions
+/- bowel obstruction, blood in stools, fatigue, weight loss.
What are the RFx for CD?
- White ancestry
- Age 15 - 40, or 60 - 80y
- FHx of CD
What tests should be ordered investigating CD?
FBE (anaemia, leukocytosis); iron studies (normal, or iron deficiency); B12 (normal or low); serum folate (normal or low); CRP (elevated).
Plain abdo films (small or large bowel dilation, calcification), barium meal (skip lesions, thickening, ulceration, fistulae) CT abdo.
What barium meal/CT findings indicative of CD?
Skip lesions, bowel wall thickening, surrounding inflammation, abscess, fistulae.
What endoscopy/colonoscopy findings indicative of CD?
- Aphthous ulcers
- hyperaemia, oedema,
- cobblestoning,
- skip lesions.
DDx for CD?
UC (colonoscopy differentiates - rectal and contiguous)); infectious colitis (Hx sick contacts and travel); pseudomembranous colitis (recent Ab use).
How does Crohn’s disease usually present?
Acute: RIF pain and tenderness (may mimic appendicitis). Or fx of low SBO.
Chronic: weight loss, colicky abdo pain and diarrhoea.
How should CD be managed?
Smoking cessation, diet (fluid during exacerbation, supplementation), antidiarrhoeals, 5-ASA, Antibiotics, corticosteroids, immunosuppressives, biologicals, surgical treatment.
Considerations regarding antidiarrhoeals in CD?
Loperamide drug of choice.
Caution if colitis is severe (risk of toxic megacolon).
What is 5-ASA?
Sulfasalazine.
Chemically similar to aspirin==> 5-ASA bound to sulfapyradine to prevent absorption by stomach. Bacteria hydrolyse to release 5-ASA.
What are the features of Crohn’s disease?
CHRISTMAS: Cobblestones (Radiology appearance) High temperature Reduced lumen Intestinal fistulae, Infliximab Skip lesions Transmural (all layers, may ulcerate) Malabsorption Abdominal pain Submucosal fibrosis
What is the role of immunosuppressives in Crohn’s disease management?
6-mercaptopurine, azathioprine, methotrexate.
Maintain remission rather than treat active.
What are the side effects of immunosuppressives used in Crohn’s disease?
Vomiting, pancreatitis, bone marrow suppression, increased risk of malignancy.
What are the biologicals used to treat Crohn’s disease?
Infliximab IV or adalimumab ==> antibody to TNFa.
Proven effective for treatment of fistulae.
Improves immunosuppressives activity.
What is the role of surgery in CD?
Complications (fistulae, obstruction, abscess, perforation, bleeding); failure to thrive in children; intolerance of medical therapy.
If risk of short bowel syndrome.
What are the complications of ileal resection?
watery diarrhoea (impaired bile salt absorption). Rx = cholestyramine, loperamide. >100cm resected --> steatorrhoea (reduced SA, bile salt deficiency). Rx = fat restriction.
What is UC?
Inflammatory disease affecting colonic mucosa from rectum to caecum. RECTUM ALWAYS INVOLVED.
Describe epidemiology of UC.
- Prevalence 35-100/100,000.
- 2/3 onset by 30y
- M=F
- Risk less in smokers
Describe the inflammation of UC.
Diffuse, continuous and confined to mucosa.
What are the clinical features of UC?
- Chronic disease characterised by diarrhoea and rectal bleeding, +/- cramps.
- Tenesmus, urgency, incontinence
- Systemic: fever, anorexia, LoW, fatigue
- Extra-intestinal manifestationss
- Characteristic exacerbations and remissions.
Ix in UC?
- Sigmoidoscopy/colonoscopy (contraindicated in severe exacerbation)
- Stool culture, microscopy (exclude C diff)
Rx of UC?
- 5-ASA (topical, oral)
- Corticosteroids (remit acute disease e.g. methylprednisolone 30mg IV q12h).
- Immunosuppresants (cyclosporine, infliximab; azathioprine)
- Surgical Rx - aim for cure with colectomy
First step UC flare management?
Admission for IV steroids: hydrocortisone 400mg daily or methylprednisolone 60mg daily.
Reevaluate after 3d.
3d assessment during UC flare up management?
Adequate response = transition to oral red 40mg. Add azathioprine pre discharge.
Inadequate = >8 stools/day or 3-8 + CRP >45. Contingency planning with surg.
What are the complications of UC?
Similar to CD +:
- More liver problems (esp primary sclerosing cholangitis)
- Increased CRC risk
- Toxic megacolon
How can the severity of UC be assessed?
Truelove and Witt’s Classification of severity.
6+ bowel motions per day associated with one other severe criterion (temperature, HR, Hb, CRP).
What are the indications for surgery in ulcerative colitis?
- Severe exacerbation
- toxic colon
- chronic colitis
- dysplasia/neoplasia
What are the surgical options to manage UC?
- Proctocolectomy with permanent ileostomy
- Ileorectal anastomosis after colectomy
- Continent ileostomy
What is proctocolectomy with permanent ileostomy?
Surgical removal of the rectum and all or part of the colon. Most widely accepted for UC and FAP. End of ileum brought through abdo wall to form a stoma.
Describe the process of iliorectal anastomosis after colectomy in UC.
In pts with less severe rectal disease, ileorectal anastomosis may be possible. Risk of subsequent carcinoma/recurrence of inflammation in the rectum.
