Inflammatory Bowel Disease Flashcards
What is the definition of Crohn’s disease?
Inflammatory disease affecting:
- the whole thickness of bowel wall
- in any part of the GIT (mouth to anus)
Characterised by:
- skip lesions
- granulomatous nature
What are the peak age of incidence for Crohn’s?
20s
50 - 70
What is the aetiology of IBD?
Immune reaction to commensal flora in genetically susceptible individuals triggered by some environmental factor
What are the risk factors of Crohn’s disease?
Genetic - over 30 genes linked with Crohn’s
Diet
Smoking - increases flare up risk
Innate immunodeficiency
Certain microbes
What is the pathophysiology for Crohn’s disease?
Abnormal immune response to gut flora
Mediated by T-helper-1 cells and macrophages
Leads to:
- inflammation = infiltration of bowel wall by neutrophils
[] granulomas found in ~50%
- tissue damage
- fibrosis
What is the macroscopic appearance of Crohn’s?
Sharply defined skip lesions - may affect full thickness of bowel wall
- ulceration
- strictures, fissures, fistulae may develop
Affected sites
- mainly distal ileum
- but can affect anywhere in GIT
What is the microscopic appearance of Crohn’s?
Infiltration of neutrophils
Crypt and villous damage
Granulomas
- aggregations of large macrophages
- non-casseated (cheese looking) as in TB granulomas
Metaplasia may occur
What are the signs and symptoms of Crohn’s?
Presentation may be subtle in contrast to UC
Variation of symptoms according to site
GI symptoms:
- abdo pain
- bloating and flatus
- diarrhoea +/- blood
- intestinal stenosis/obstruction
- discomfort/ sores around anus +/- mouth
Systemic symptoms
- anorexia
- weight loss
- fever
- dietary deficiency => osteoporosis, anaemia (pernicious)
Other:
- uveitis
- rheumatological disease
- dermatological disease
- neurological symptoms
What investigations should be done for Crohn’s disease?
Bloods
- FBC
- ESR and CRP
- Antibody serologies
X-ray: strictures/fistulae
- barium follow through
- barium enema
Colonoscopy +/- gastroscopy (can’t explore small bowel)
-> +/- biopsy = may aid diagnosis
What are the complications of Crohn’s?
Obstruction
Fistulae
Abcesses
Short bowel syndrome (due to repeated resections)
GI cancer - increased risk due to metaplasia
What is the prognosis of Crohn’s?
Chronic
No dramatic effect on mortality
Greater impact on QoL
What is ulverative colitis?
Inflammatory disease affecting the mucosal layer of the colon and recum
Characterised by:
- Continous distribution
- Non-granulomatous nature
Secondary symptoms may affect other body parts
Which gender is affected more and what is the peak age of onset?
Female > Male
Peak age: 20 - 25
What are the risk factors for UC?
Genetic factors
Family Hx of autoimmune disease / porhphryias (enzyme disorder in heme pathway)
Diet
What is the pathophysiology of UC?
Abnormal immune response to gut flora
Mediated by T-helper-2 cells and B cells which produce autoantibodies
What is the macroscopic appearance of UC?
Inflammation of mucosal layer only
Starts in rectum and may affect any length of colon from rectum up, occasionally the distal ileum too
- 60% limited to rectum and sigmoid colon
- only 15% have pancolitis (total large bowel)
Continuous distribution with no skip lesions
What is the microscopic appearance of UC?
Uniform, diffuse inflammation of the mucosa
- acute and chronic inflmmatory cell in lamina propria
- neutrophils in crypt epithelium and crypt lumen (acute cryptitis and crypt abcesses)
- distorted crypts and loss of mucin production
- congestion of blood vessels
What are the signs and symptoms of UC?
GI symptoms
- diarrhoea: blood and mucous mixed with stool
- cramping of lower abdomen
- pain: left lower quadrant with distal disease extending to entire abdomen with pancolitis
- tenesmus: constant urge to defecate
Non GI symptoms:
- Fevers (40%)
- Weight loss (less than crohn’s though)
- Arthralgia/arthritis: peripheral large joints and axial
What are the investigations of UC?
Stool examination: - microbiol - toxins
Bloods:
- FBC
- Inflammatory markers: CRP, ESR
- U&Es: hypokalaemia & hypomagnesaemia => diarrhoea
- LFTs: exclude primary sclerosing cholangitis (5%)
Abdominal X ray
- exclude toxic megacolon: determines disease extent
Endoscopy (colonoscopy) and biopsy
How can UC be cured?
Total colectomy
Will leave patient with no colon though
What are the complications of UC?
Primary sclerosing cholangitis (5%)
Bowel cancer
Toxic megacolon
What is the prognosis of UC?
Most sufferers enter remission
- 20% without treatment
- severe sufferers less likely to sustain remission
~ 40% will require surgery within 20 years
