Small bowel disease Flashcards
What are the causes of inflammatory bowel disease?
- Environmental factors: diet, sanitation, medication
- Genetic predisposition
- Host immune response: related to psoriasis, ankylosing spondylitis
- Gut microbiota
What kind of bowel opening is almost always pathological?
Nocturnal
What is the classical presentation of infective colitis?
- Short history of diarrhoea +/- vomiting
- Abrupt onset +/- resolution of symptoms
- Systemic upset and fevers prominent
- Travel
- Unwell contacts
- Immunocompromised
What is the investigation for suspected infective colitis?
Stool culture - need at least 4 for 90% sensitivity
What is the treatment for infective colitis?
Normally conservative if immunocompetent
What is the classical presentation of ischaemic colitis?
- Abrupt onset of pain
* bloody diarrhoea +/- SIRS
What are the risk factors for ischaemic colitis?
- Elderly
- Cardiovascular disease
- Heart failure
What may be seen on a CT scan in someone with ischaemic colitis?
May show segmental colitis in watershed areas
What is the treatment of ischaemic colitis?
- IV fluids
* Consider antibiotics if systemic features
Above what number of bloody stools a day should you admit a patient, regardless of other symptoms?
> 6
What are the signs of ulcerative colitis on an abdominal X-ray?
Thumb printing due to extensive bowel wall thickening
What can be evaluated/seen in an abdominal X-ray which you should be worried about in someone with ulcerative colitis?
- Megacolon
* toxic megacolon
What is the difference between megacolon and toxic megacolon?
- Megacolon: diameter>5.5cm or caecum >9cm
* Toxic megacolon: megacolon and signs of systemic toxicity
What causes a megacolon in ulcerative colitis?
Inflammation in the colon causes gas to get trapped resulting in the colon becoming enlarged and swollen
What investigations should be carried out in someone with suspected ulcerative colitis?
- Abdominal X ray
- Flexible sigmoidoscopy or colonoscopy
- Potentially a CT scan
What are the layers of the normal bowel wall starting at the luminal surface?
- Mucosa
- Sub mucosa
- Muscularis
- Sub-serosa
What are the two components of the muscularis in the bowel wall?
- Inner circular
* Outer longitudinal
Describe the lamina propria
- Supporting scaffold of connective tissue
- contains a few inflammatory cells
- Fibroblasts, blood vessels, lymphocytes, plasma cells, a few eosinophils
What are the acute pathological changes in inflammatory bowel disease?
- Acute inflammation
- Ulceration
- Loss of goblet cells
- Crypt abscess formation - collection of neutrophils
What are the chronic pathological changes in IBD?
- Architectural changes
- Paneth cell metaplasia (in more distal bowel)
- Chronic inflammatory infiltrates in the lamina propria (more plasma cells)
- Neuronal hyperplasia
- Fibrosis
In ulcerative colitis, where is the inflammation confined to?
The mucosa
In regards to the histopathology, what is lost in inflammatory bowel disease which is not lost in infective colitis?
The plasma cell gradient - normally there are more plasma cells on the luminal side of the bowel wall whereas in IBD there are increased plasma cells throughout the whole of the bowel wall
What are the macroscopic features of ulcerative colitis?
- Diffuse involvement of the lower GIT
* The terminal ileum can be involved but generally only if severe
What are the microscopic features of ulcerative colitis?
- Crypt architectural changes are generally very marked
- Little to no fibrosis
- No granulomas
What drugs can be prescribed for chronic ulcerative colitis
- 5-ASA/mesalazine both orally and topically (foam enema or suppository)
- Azathioprine/6MP (severe relapses/frequently relapsing)
What is the treatment of an acute severe ulcerative colitis?
- IV steroids e.g. methylprednisolone
* Low molecular weight heparin
What can predict the need for a colectomy in those with an acute severe ulcerative colitis?
Either of the following on day 3 of treatment:
•Stool frequency >8 a day
•Stool frequency >3 and CRP > 45
What are the rescue medical therapy for those with ulcerative colitis
Infliximab or ciclosporin
What is infliximab?
•Monoclonal antibody to TNF-alpha
What are the local complications of ulcerative colitis?
- Haemorrhage
* Toxic dilation (aka toxic megacolon)
What are the systemic complications of ulcerative colitis?
- Skin: erythema nodosum( red bumps and patches), pyoderma gangrenosum (painful ulcers)
- Liver: sclerosing cholangitis, cholangiocarcinoma
- Eyes: iritis, uveitis, episcleritis
- Ankylosing spondylitis
- malignancy
What surveillance should be done in those with ulcerative colitis?
Screening colonoscopies:
•If no active inflammation: once every 5 years
•If mild active inflammation: once every 3 years
•If moderate/severe inflammation; once a year
Which of the IBDs is more likely to cause a high MCV?
Chron’s - due to the effect on the absorption of B12
What is Chron’s disease?
Ac chronic inflammatory condition affecting anywhere from the mouth to the anus
Where are the most common sites of Chrons?
The terminal ileum and caecum
What is the peak incidence of Chron’s disease?
15-25 years
What lifestyle change can someone with Crohn’s do to reduce the risk of relapse?
Stop smoking
What are the features of Crohn’s disease?
- Abdominal pain
- Diarrhoea
- Weight loss
- Fistulae, abscesses, oropharyngeal, gastroduodenal
- Extra-intestinal symptoms
What are the extra-intestinal symptoms of crohn’s disease?
- Eyes: uveitis and episcelritis
- Joints: sacroilitis, inflammatory arthropathy
- Skin: erythema nodosum
What investigations should be carried out in suspected Crohn’s disease?
- Abdominal Xray
- Ileocolonoscopy
- Faecal calprotectin
- Stool cultures
- MR/CT enterography
What is faecal calprotectin?
Calcium binding protein, predominantly derived from neutrophils
What is faecal calprotectin useful for?
Differentiating between IBD and IBS
What can be seen on histology of the bowel which would confirm Crohn’s?
Granulomas
How can a pathologist tell the difference between ulcerative colitis and Crohn’s?
- Distribution of the inflammation
- Type of inflammation
- Clinical context/scope findings
What are the differences between Crohn’s and ulcerative colitis?
- Crohn’s = small and large bowel inflammation, UC= large bowel only
- Crohn’s tends to involve the proximal large bowel, UC tends to extend from the rectum to involve left side of bowel
- Crohn’s= patchy inflammation with skip lesions , transmural deeply ulcerating, UC= confluent, diffuse inflammation centred on mucosa
What is the classification system of crohn’s?
The Montreal category
What are the medications for Crohn’s?
•Azathioprine and 6-mercaptopurine •Methotrexate •Biologics: - TNF alpha antagonists - Anti-integrins - Anti-interleukin
What are the risk factors for needing surgery in Crohn’s disease?
- Young onset
- smoking
- Perianal disease
- Stricturing SB disease
