Crohn's Disease Flashcards
What is Crohn’s disease?
A chronic inflammatory disease
What is Crohn’s characterised by?
Transmural granulomatous inflammation affecting any part of the gut from mouth to anus, especially the terminal ileum or proximal colon
What % of Crohn’s patients have involvement of the terminal ileum?
70%
What are areas of unaffected bowel called in Crohn’s disease, and why are they significant?
Skip lesions
They differentiate from UC, which has continuous inflammation
How is the pathophysiology of Crohn’s similar to UC?
Like UC, it is caused by inappropriate immune response against the gut flora in a genetically susceptible individual
When does Crohn’s disease present?
Typically 20-40 years
What is produced by the transmural inflammation in Crohn’s?
Deep ulcers and fissures
What kind of appearance is produced by deep ulcers and fissures in Crohn’s?
Cobblestone appearance
Describe the microscopic appearance of Crohn’s?
Non-caseating granulomatous inflammation
What is the result of the transmural nature of the inflammation?
Fistulas can form from the affected bowel to adjacent structures, resulting in perianal fistulas, recto-vaginal fistulas, entero-cutaneous fistulas, or enterovescicular fistulas
What causes Crohn’s disease?
Exact cause is unknown, seems to be combination of environmental factors and genetic predisposition
What is it suggested that Crohn’s is due to?
Genetic malfunction in the innate immune system, causing adaptive immune system to compensate for it, thus causing chronic inflammation
What genes are implicated in Crohn’s disease?
NOD2/CARD15
What are the risk factors for Crohn’s?
- Genetics
- Smoking
- Intercurrent infections, e.g. URTI, enteric infection
- NSAID use
What are the symptoms of Crohn’s?
- Diarrhoea, may be bloody and become chronic
- Abdo pain
- Weight loss/failure to thrive
- Systemic symptoms
What are the systemic symptoms of Crohn’s?
- Fatigue
- Fever
- Malaise
- Anorexia
Describe the course of Crohn’s
There will typically be periods of acute exacerbation, interspersed with remissions or less active disease
How might oral involvement of Crohn’s present?
Apthous mouth ulcers, which can be painful and recurring
How might perianal Crohn’s present?
- Skin tags
- Perianal abcesses
- Bowel stenosis
What are the signs of Crohn’s disease?
- Bowel ulceration
- Abdominal tenderness
- Abdominal mass
- Perianal abscess
- Perianal fistulae
- Anal strictures
- Clubbing
- Skin, joint, and eye problems
What investigations should be done in Crohn’s disease?
- Bloods
- Stool MC&S
- Faecal calprotectin
- Colonoscopy and biopsy
- Imaging
What bloods should be done in Crohn’s disease?
- FBC
- ESR
- CRP
- U&E
- LFT
- INR
- Ferritin
- TIBC
- B12
- Folate
Why should stool MC&s be done in Crohn’s?
Rule out infectious causes
What is the gold standard for diagnosis in Crohn’s?
Colonoscopy with biopsy
What is the characteristic macroscopic finding for Crohn’s on colonoscopy?
Cobblestoning of the bowel
What is cobblestoning of the bowel?
Where fissures and ulcers seperate islands of healthy mucosa
When should colonoscopy be avoided in Crohn’s?
During active flares
Why should colonoscopy be avoided during active flares of Crohn’s?
Due to increased risk of peritoneal performation
What might be needed for investigation of Crohn’s during an active flare?
Flexible sigmoidoscopy
What other imaging can be done in Crohn’s?
- Capsule endoscopy
- MRI
- Ultrasound
- CT scan
- Barium swallow
What can capsule endoscopy be used to detect in Crohn’s?
Isolated proximal disease
What might MRI be used for in Crohn’s?
Assess pelvic disease and fistulae, small bowel disease activity, and strictures
What can ultrasound be used for in Crohn’s?
Can sometimes provide small bowel imaging
When is CT used in Crohn’s?
Severe disease
What can CT show in Crohn’s?
- Bowel obstruction
- Perforation
- Collection formation
- Fistulae
What can barium swallow show in Crohn’s?
- Strictures
- ‘Rose thorn’ ulcers
- String sign of Kantor
What will management of Crohn’s disease involve?
Induction of remission, and once this is achieved maintenance of remission
What is first line in induction of remission of Crohn’s?
Monotherapy with conventional glucocorticoid steroid, e.g. prednisolone
When can prednisolone be used for induction of remission in Crohn’s?
- First presentation
- Single inflammatory exacerbation of Crohn’s disease in 12 month period
What is second line for induction of remission in Crohn’s?
- Budesonide in people with distal ileal, ileocaecal, or right-sided Crohn’s disease
- Mesasalazine in others
How does budesonide and mesasalazine compare to prednisolone in induction of remission of Crohn’s?
Budesonide is not as effective, but may have fewer side effects
Mesasalazine is less effective than both
When should budesonide and mesasalazine not be used?
In people with a severe presentation or exacerbation
What can you consider adding to conventional first line treatment for induction of remission in Crohn’s?
Azathioprine or mercaptopurine
When may you consider adding azathioprine or mercaptopurine to conventional first line treatment for induction of remission in Crohn’s?
If there have been 2 or more inflammaotry exacerbations in a 12 month period, or the glucocorticosteroid dose cannot be tapered down without symptoms
What can be used instead of azathioprine or mercaptopurine if these are not tolerated or contraindicated?
Methotrexate
What should be done if first line therapy + metacaptopurine/azathioprine is still insufficient in induction of remission of Crohn’s?
Biological treatment such as infliximab or adalimumab, either as monotherapy or combined with immunosuppressant
When are biological therapies recommended in induction of remission of Crohn’s?
- Adults with severe active Crohn’s disease that has not responded to conventional therapy
- Intolerant to these therapies
How long should biological therapies be continued in induction of remission in Crohn’s?
12 months, unless not effective (then stop)
What can be used as an alternative to medical treatment in early course of Crohn’s?
Surgery
When can surgery be used as an alternative to medical treatment in the early course of Crohn’s
When disease is limited to distal ileum
What are the first line drugs in maintenance of remission of Crohn’s?
Azathioprine or mercaptopurine
When should methotrexate be considered as an option in maintenance of remission of Crohn’s?
- Needed to induce remission
- Tried but did not tolerate first line
- Contraindications to these agents
What is required with methotrexate, azathioprine, or mercaptopurine?
Monitoring
What further management may be required with Crohn’s?
- Referral to IBD nurse specialist and patient support groups
- Enteral nutritional support
- Antibiotics
When might enteral nutritional support be considered?
In young patients with growth concerns
When might antibiotics be used in Crohn’s?
Only in those with obvious concurrent infection or perianal disease
What antibiotics are typically used in Crohn’s?
- Ciprofloxacin
- Metronidazol
What % of Crohn’s patients need surgery at some point in their lifetime?
70-80%
Who is surgery indicated in with Crohn’s?
- Failed medical managment
- Severe complications, e.g. strictures and fistulae
- Growth impairment in younger patients
What is the most common surgical procedure in Crohn’s?
Ileocaecal resection
What is an ileocaecal resection?
Removal of the terminal ileum and caecu, with primary anastomosis between ileum and ascending colon
What approach needs to be taken during surgery for Crohn’s, and why?
Bowel sparing approach, to prevent short-gut syndrome in later years
What are the complications of Crohn’s?
- Stricture formation
- Fistulas
- Perianal complications
- GI malignancy
What can stricture formation in Crohn’s lead to?
Bowel obstruction and perforation
What strictures might form in Crohn’s?
- Enterovesical
- Enterocutaneous
- Rectovaginal
What perianal complications may arise in Crohn’s?
Formation of perianal abcesses or fistulae
What is the risk of GI malignancy in Crohn’s?
3% risk of developing colorectal cancer over 10 years
30x higher risk of developing small bowel cancer than general population
How can fistulas be managed?
- Fistulotomy (opening tract up)
- Seton technique
What happens in Seton technique?
Cord is tied around fistula which keeps ot open, and over time it drains and heals over
In what extra-intestinal systems might Crohn’s manifest?
- MSK
- Skin
- Eyes
- Hepatobiliary
- Renal
What are the MSK manifestations of Crohn’s?
- Enteropathic arthritis
- Metabolic bone disease
What causes metabolic bone disease in Crohn’s?
Malabsorption
What are the skin manifestations of Crohn’s?
- Erythema nodosum
- Pyoderma gangrenosum
What are the eye manifestations of Crohn’s?
- Episcleritis
- Anterior uveitis
- Iritis
What are the hepatobiliary manifestations of Crohn’s?
- Primary sclerosing cholangitis
- Cholangiocarcinoma
- Gallstones
What are the renal manifestations of Crohn’s?
Renal stones