Inflammatory Bowel Disease Flashcards
Define IBD.
Chronic idiopathic inflammatory condition affecting the bowel encompassing two related but distinct disorders: ulcerative colitis (UC) and Crohn’s disease (CD).
Explain the aetiology/risk factors for IBD.
Unknown aetiology, likely 2 to environmental factors (infections, medications) triggering a response in genetically susceptible patients (multiple genes identified).
Genetic component: CD > UC.
Smoking: increased CD risk and decreased UC risk.
What is the pathophysiology of UC?
Diffuse mucosal inflammation of the rectum extending proximally (variable length). Subdivision into distal (proctitis and proctosigmoiditis) and extensive disease (left-sided or extensive colitis and pancolitis).
Macro: Mucosal erythema, friability, ulceration and inflammatory pseudopolyps.
Micro: Distortion of crypt architecture, inflammatory cell infiltrate, goblet cell depletion and crypt abscesses.
What is the pathophysiology of CD?
Patchy transmural inflammation affecting one or several segments of the intestinal tract (segmental/skip lesions). Defined by anatomical location or pattern of disease (inflammatory, fistulating or stricturing).
Macro: Mucosal (oedema/fibrosis), deep ulceration (serpiginous or fissuring), fistulas.
Micro: Transmural inflammation, lymphoid aggregates, non-caseating granulomas.
What is indeterminate colitis?
10% of children are unclassifiable as features of both conditions present.
Summarise the epidemiology of IBD.
5.2/100,000 (<16 years); 60% CD, 28% UC and 12% IC. Mean age (diagnosis): 11.9 years. Bimodal peaks at 10 and 40 years.
What are general presenting signs and symptoms of IBD?
UC characterised by exacerbation and remission episodes (50% relapse per year), skin manifestations rare, typically present with bleeding/diarrhoea/abdominal pain. CD are more heterogeneous and non-specific; classic triad now uncommon (abdominal pain/diarrhoea/weight loss).
What are common presenting signs and symptoms of IBD?
Abdominal pain (CD 72%, UC 62%, IC 72%), diarrhoea (CD 56%, UC 74%, IC 78%), rectal bleeding (CD 22%, UC 84%, IC 49%), weight loss (CD 58%, UC 31%, IC 35%), lethargy (CD 27%, UC 12%, IC 14%) and anorexia (CD 25%, UC 6%, IC 13%).
What are additional presenting signs and symptoms of IBD?
Arthropathy, N&V, constipation, encopresis, psychiatric symptoms, secondary amenorrhoea.
What are common signs of IBD?
Anal fistula, growth failure/delayed puberty, anal abscess/ulcer, erythema nodosum/rash, liver disease, toxic megacolon.
What are appropriate investigations for IBD?
General: ESPGHAN IBD Working Group consensus protocol. Bloods: low Hb, high ESR/CRP, serum folate, B12, LFTs (abnormality requires investigation with ERCP, USS and biopsy for primary sclerosing cholangitis (PSE)), albumin.
Specific: Limited use of perinuclear antineutrophil cytoplasmic antibody (pANCA) with UC and anti-Saccharomyces cerevisiae antibody (ASCA) with CD; sensitivity.60–80%.
Microbiology: Stool culture (infective causes), Clostridium difficile toxins A and B.
Radiology: AXR (toxic dilation), small bowel follow-through, technetium white cell scanning (highlights areas of inflammation).
Endoscopy: Ileocolonoscopy and upper GI endoscopy with histology of multiple biopsies from all segments.
What is the management plan for UC?
Induction – ASA/sulphasalazine or corticosteroids
Maintenance – AZA/mesalazine
2nd line – AZA/6-MPU
Surgery for toxic megacolon or resistance to medical treatment
What is the management plan for CD?
1st line - Exclusive liquid enteral nutrition -> corticosteroids -> aminosalicylates (mesalazine/sulphasalazine) -> budesonide -> IV steroid (add antiobiotics for perianal disease)
2nd line – AZAm parenteral nutrition
3rd line – Infliximab and surgery
Remission maintenance: AZA/6-MPU
What are some complications associated with UC?
Toxic megacolon, perforation, colorectal carcinoma, PSE.
What are some complications associated with CD?
Megaloblastic anaemia, gallstones, perianal disease (tags, fissures, fistulas, purulent discharge), strictures, obstruction.
