Inflammatory bowel disease (GI) Flashcards
What does IBD consist of?
- Crohn’s disease
- ulcerative colitis
Define Crohn’s disease.
Disorder of unknown aetiology characterised by transmural inflammation of the GI tract
What parts of the GI tract can Crohn’s disease affect?
May involve any or all parts of the entire GI tract from mouth to perianal area, although usually seen in the terminal ileal and perianal locations
Most commonly ileum+colon, then just ileum, then just colon
What is Crohn’s disease characterised by?
Skip lesions (normal bowel mucosa between diseased areas, unlike ulcerative colitis)
What can the transmural inflammation in Crohn’s disease often lead to? (2)
- fibrosis –> intestinal obstruction
- sinus tracts that burrow through and penetrate serosa –> perforations and fistulae
What demographics does Crohn’s disease affect?
- M=F
- 2 age peaks: 15-40 years (main peak) and 60-80 years
Describe the aetiology of Crohn’s disease.
- thought to be caused by an interaction of infectious, environmental, dietary, immunological features in a genetically susceptible person
- genetic factors - CARD 15 which codes NOD2 pathogen recognition protein
- environmental factors - smoking, OCP, high sugar diet, nutritional deficiencies (zinc), infections (measles)
- breakdown of immune tolerance to normal gut microbiome –> unregulated inflammation
- inflammatory infiltrate around intestinal crypts –> ulceration of superficial mucosa –> deeper layer penetration to form non-caseating granulomas (masses of immune cells)
What layers of the intestinal wall do granulomas involve in Crohn’s disease?
All layers of the intestinal wall (transmural) and mesentery and regional lymph nodes
What are the clinical features of Crohn’s disease? (8)
- RLQ/peri-umbilical abdominal pain if ileitis is present, may be relieved by defecation
- prolonged diarrhoea (usually non-bloody)
- perianal lesions (skin tags, fistulae, abscesses, scarring, sinuses)
- bowel obstruction (due to acute inflammatory oedema or chronic scarring and stricture)
- blood in stools
- fever
- fatigue (due to malabsorption –> weight loss and anaemia too)
- abdominal tenderness/mass
What features of bowel obstruction might you see in Crohn’s disease? (8)
- bloating
- distension
- cramping
- abdominal pain
- loud borborygmi
- vomiting
- constipation
- obstipation (severe constipation)
How does malabsorption show itself in Crohn’s disease?
Weight loss, anaemia and fatigue
What extraintestinal symptoms are seen in Crohn’s disease? (5)
- oral lesions - mouth ulcers
- arthropathy - joint pain
- skin lesions - erythema nodosum (on shins) and pyoderma gangrenosum (ulcers on legs –> give prednisolone PO)
- ocular symptoms - anterior uveitis (painful red eye with vision loss and photophobia) + episcleritis (painless red eye)
- clubbing
What are some risk factors for Crohn’s disease? (7)
- ethnicity: white, Jewish
- age 15-40 or 50-60
- Fx of Crohn’s disease
- smoking (NB smoking reduces risk of UC)
- diet: high refined sugar, low fibre, high ultra-processed foods
- OCP
- NSAIDs
What are the 1st line investigations for Crohn’s disease?
- FBC
- iron studies (serum iron, ferritin, TIBC, transferrin saturation)
- serum vitamin B12
- serum folate
- comprehensive metabolic panel (CMP)
- CRP & ESR
- stool testing
- plain abdominal x-ray
- MRI abdomen/pelvis
- CT abdomen
What would you see on colonoscopy and biopsy of Crohn’s disease? (6)
- deep ulcers & rose-thorn ulcers
- skip lesions
- cobblestone appearance
- increased goblet cells
- lymphoid aggregates in mucosa
- distortion of crypts
What would you see on histology of Crohn’s disease?
Transmural inflammation with non-caseating granulomas
What would we see on a barium enema in Crohn’s disease? (2)
- Kantor’s string sign
- rose-thorn ulcers
What would we look for in bloods for Crohn’s disease? (6)
- anaemia (due to chronic inflammation, chronic blood loss, iron and B12/folate malabsorption)
- leukocytosis
- thrombocytosis
- increased CRP & ESR
- raised serum vitamin B12 (absorbed in terminal ileum) and folate
- raised faecal calprotectin
Why would we do stool MC&S in Crohn’s disease?
To exclude infections
What might we see on CT abdo/MRI for Crohn’s disease?
- visualise skip lesions
- bowel wall thickening
- surrounding inflammation
- abscess
- fistulae
What stool test is important in Crohn’s disease?
Faecal calprotectin - looks for inflammation
What are some differential diagnoses for Crohn’s disease?
- UC (left-sided abdo pain and bloody diarrhoea, no small bowel/oral/perineal disease, always rectum and is contiguous on endoscopy)
- infectious colitis
- pseudomembranous colitis (recent Abx, C. diff, no ulceration)
- ischaemic colitis
- radiation colitis
- Yersinia enterocolitica
- intestinal TB
- amoebiasis
- cytomegalovirus colitis
- colorectal cancer
- diverticular disease (L-sided pain)
- acute appendicitis
- ectopic pregnancy
- PID
- endometriosis
- IBS (not bloody or nocturnal)
What should all patients with Crohn’s disease be advised to do?
Stop smoking
What does acute management of Crohn’s disease involve? (5)
- fluid resuscitation
- oral iron
- analgesia
- TPN or EN
- monitor ESR/CRP, Hb, platelets
How do we induce remission in Crohn’s disease with 1st presentation/exacerbation?
- 1st line: glucocorticoid (prednisolone, methylprednisolone or IV hydrocortisone)
- 2nd line: budesonide (if non-severe) OR 5-ASAs (mesalazine and olsalazine)
- 3rd line: add immunosuppressants/immunomodulators (azathioprine, mercaptopurine, methotrexate) - contraindicated by deficient thiopurine methyltransferase activity
- 4th line (if refractory): anti-TNFa biologics (infliximab, adalimumab)
What do we use to induce remission in isolated peri-anal Crohn’s disease?
Metronidazole
How do we maintain remission in Crohn’s disease?
- NO STEROIDS
- 1st line: immunosuppressants/immunomodulators (azathioprine, mercaptopurine) - monitor FBC as can reduce WBC
- 2nd line: methotrexate
- 3rd line: 5-ASAs
- smoking cessation
When is surgery done for Crohn’s disease?
- medical treatment fails
- failure to thrive in children with complications
- involves resection of affected bowel and stoma formation
- NB there is a risk of disease recurrence
How are perianal abscesses in Crohn’s disease dealt with?
- incision and drainage
- uncomplex perianal fistula = Abx (oral metronidazole or ciprofloxacin)
- complex perianal fistula = seton
What may severe perianal or rectal Crohn’s disease require?
Proctectomy (ileoanal pouch not usually done)
What are some complications of Crohn’s disease?
- intestinal obstruction
- pregnancy complications due to immunosuppressant therapy (do not continue methotrexate)
- intra-abdominal sepsis
- sinuses
- toxic megacolon
- anaemia (terminal ileum where B12 absorbed)
- fistulas (perianal = fistulotomy or draining seton, MRI to visualise to treat)
- strictures
- malignancy & short-bowel syndrome
- kidney stones & gallstones
- abscess (incision and drainage)
What is the prognosis of Crohn’s disease like?
Chronic disease with variable frequency of relapses and multiple possible complications. However, appropriate medical and surgical treatment may enable patients to have a reasonable QOL.
Define ulcerative colitis.
Type of IBD that characteristically involves the rectum and extends proximally to affect a variable length of the colon
What side of the GI tract does ulcerative colitis affect?
- rectum and extends proximally to a variable length of colon
- proctitis: when only rectum involved
- pancolitis: entire colon involved
What part of the bowel is most commonly affected in ulcerative colitis?
Rectum
What layer of bowel walls does ulcerative colitis affect?
Colonic mucus only
(VS Crohn’s = transmural)
What demographic does ulcerative colitis affect?
Peak incidence in 20-40 year olds
Another small one in >60
What activity has a protective effect on ulcerative colitis?
Smoking
Describe the aetiology of ulcerative colitis.
- breakdown of immune tolerance to normal gut microbiome, occurring in genetically susceptible individuals with environmental triggers
- thought to be autoimmune disease initiated by an inflammatory response to colonic bacteria and immune dysfunction
- inflammation only of mucosa –> crypt abscesses and depletion of goblet cell mucosa
- ulcerated areas become covered by granulation tissue which eventually forms inflammatory polyps or pseudopolyps
- thin-walled dilated colon –> fulminant colitis/toxic megacolon –> perforation –> peritonitis
What happens in fulminant colitis?
Rapid and extensive colonic dilatation –> toxic megacolon
What is toxic megacolon?
Severe episode of colitis with segmental or total dilatation of the colon (result of fulminant colitis) –> nerves and muscles damaged so colon becomes dilated and atonic –> buildup of gas + faeces with ileus
What can happen in chronic severe ulcerative colitis?
Precancerous changes e.g. carcinoma in situ or dysplasia
NB risk of cancer is higher in UC vs Crohn’s
What are the clinical features of ulcerative colitis? (7)
- rectal bleeding associated with mucus
- diarrhoea (bloody)
- blood in stool
- abdominal pain (LLQ) & cramps
- faecal urgency & tenesmus (suggestive of proctitis)
- fever & weight loss
- extra-intestinal symptoms
What are the extra-intestinal symptoms of ulcerative colitis? (3)
- joints - peripheral arthritis and ankylosing spondylitis
- skin - erythema nodosum and pyoderma gangrenosum
- ocular - episcleritis > uveitis
How do we distinguish between mild, moderate and severe ulcerative colitis?
- mild: <4 bowel movements per day, only small amount of blood
- moderate: 4-6 bowel movements per day, varying blood, no systemic upset
- severe: 6+ bowel movements per day + visible blood + systemic upset : pyrexia + HR>90 + anaemia + ESR>30
What are the risk factors for ulcerative colitis? (6)
- Fx of IBD
- HLA-B27 association
- infection
- NSAIDs
- non-smoker
- white ethnicity / Jewish
What are the 1st-line investigations for ulcerative colitis?
- stool studies for infective pathogens
- faecal calprotectin
- FBC
- comprehensive metabolic panel (CMP)
- CRP & ESR
- plain abdo x-ray
- flexible sigmoidoscopy
- colonoscopy
- biopsies
What would colonoscopy and biopsy show in ulcerative colitis? (5)
- continuous distal disease (rectal)
- absence of granulomas
- crypt abscesses
- depletion of goblet cells
- loss of vascular markings
What investigation do we use in severe colitis and why?
Flexible sigmoidoscopy - colonoscopy should be avoided due to risk of perforation
What would bloods show for ulcerative colitis? (6)
- deranged LFTs means primary sclerosing cholangitis - majority of PSC patients have underlying IBD
- increased CRP & ESR
- anaemia
- leukocytosis
- thrombocytopenia
- may show positive ANCA (especially pANCA)
What would AXR show for ulcerative colitis? (4)
- toxic megacolon - transverse colon >6cm
- loss of haustra
- thumbprinting (large bowel wall thickening)
- pseudopolyps
What would barium enema show for ulcerative colitis?
Lead pipe appearance - smooth dilated large bowel (& thumbprinting - large bowel wall thickening in colitis)
What are some differential diagnoses for ulcerative colitis?
- Crohn’s disease - perianal involvement, rectal sparing, fistulae, endoscopy&biopsy
- indeterminate colitis
- radiation colitis
- infectious colitis
- diverticulitis
- IBS
- mesenteric ischaemia/ischaemic colitis
- vasculitis
- prolonged use of cathartics
- lymphogranuloma venereum
What is mild ulcerative colitis?
<4 stools/day, only a small amount of blood
What is moderate ulcerative colitis?
4-6 stools/day, varying amounts of blood, no systemic upset
What is severe ulcerative colitis?
> 6 bloody stools/day + features of systemic upset (pyrexia, tachycardia, anaemia, raised inflammatory markers)
How do we induce remission in mild-moderate ulcerative colitis - proctitis?
- 5-ASAs (mesalazine - an aminosalicyclate) –> topical (rectal) for distal colitis
- if remission not achieved in 4wk: add oral ASA for more severe colitis
- if still not achieved, add topical or oral corticosteroid
How do we induce remission in mild-moderate ulcerative colitis - proctosigmoiditis and left-sided ulcerative colitis?
- topical (rectal) aminosalicyclate (mesalazine)
- if remission not achieved in 4wk: add high-dose oral aminosalicyclate OR switch to a high-dose oral aminosalicyclate and a topical corticosteroid
- if still not achieved: stop topical treatments and offer an oral aminosalicyclate and an oral corticosteroid
How do we induce remission in mild-moderate ulcerative colitis - extensive disease?
- topical (rectal) 5-ASA + high-dose oral 5-ASA
- if remission not achieved in 4wk: stop topical treatments and offer a high-dose oral 5-ASA + oral corticosteroid
How do we induce remission in severe ulcerative colitis?
- should be treated in hospital
- IV steroids 1st-line (IV ciclosporin may be used if steroids contraindicated)
- if after 72h there has been no improvement, consider adding IV ciclosporin to IV corticosteroids or consider surgery
- IV fluids + NBM
- rescue therapy: infliximab
- if still fails to improve: urgent subtotal colectomy with end ileostomy
How do we maintain remission following a mild-moderate ulcerative colitis flare?
Proctitis and proctosigmoiditis:
- topical (rectal) 5-ASA alone OR
- oral 5-ASA + topical (rectal) 5-ASA OR
- oral 5-ASA by itself (less effective)
Left-sided and extensive ulcerative colitis: low maintenance dose of oral 5-ASA
How do we maintain remission in ulcerative colitis following a severe relapse or >/=2 exacerbations in the past year?
Oral azathioprine / mercaptopurine (immunosuppressants)
What drug is not recommended for management of ulcerative colitis (vs Crohn’s)?
Methotrexate
What issue can 5-ASA cause and how can we monitor it?
Agranulocytosis = monitor via FBC
How do we treat toxic megacolon (ulcerative colitis)? (5)
- NBM
- IV fluids
- NGT
- avoid colonoscopy due to perforation risk
- avoid sulfasalazine and other 5-ASA
What surgery can we do in longstanding ulcerative colitis with risk of malignant transformation?
Proctocolectomy (with ileostomy - surgical removal of colon, rectum and anal canal)
Ileo-anal pouch formation
What are some complications of ulcerative colitis? (4)
- fulminant colitis –> toxic megacolon –> perforation –> peritonitis
- primary sclerosing cholangitis (PSC) - inflammation and fibrosis of intra and extra hepatic bile ducts
- colonic adenocarcinoma (in 3-5%)
- infections - CMV, C. diff
What is primary sclerosing cholangitis (complication of ulcerative colitis)?
Inflammation and fibrosis of intra and extra hepatic bile ducts (UC + cholestasis –> jaundice + pruritus with raised ALP + GGT) –> can lead to cholangiocarcinoma of bile duct
What is the prognosis of ulcerative colitis?
Overall mortality of UC patients not increased compared to general population
