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