Flashcards in Gastrointestinal Deck (40):
What is crohn's disease?
Immune related disorder that causes inflammation in the bowel (thought to be an uncontrolled inflammatory reaction to a pathogen which leads to the destruction of healthy tissue - this is different to an autoimmune disease)
What is the most common place for crohns disease to affect?
Ileum and colon
What are symptoms of crohns disease in the mouth?
What are symptoms of crohns disease in the small intestine?
Right lower quadrant pain (associated with the ileum)
What are symptoms of crohns disease in the colon?
Lower abdominal pain
What are symptoms of crohns disease in the anus?
Is there a genetic link to IBD? if so what is it?
Yes, a positive family history is the major risk factor for disease development
Early onset disease appears to have the strongest genetic links.
The risk in first degree relatives in between 2 - 16%.
In twins the concordance for crohns disease is 36% and 16% for UC
Where does ulcerative colitis affect?
The rectum and ascends proximally
What are the three main types of UC?
Left sides colitis (27%)
What are the main symptoms of ulcerative colitis?
Determined by disease extent and severity
- Diarrhoea and bleeding
- Increased bowel frequency
- Night rising
- Lower abdominal pain (LIF especially)
How is the severity of ulcerative colitis assessed?
Truelove and Witt criteria assesses for severe UC (Severe UC has a 30% risk of colectomy)
More than 6 bloody stools in 24 hours +
1 or more of..
- Fever over 37.8 degress
- Tachycardia of over 90
- Haemoglobin less than 10.5g/dl
- Elevated ESR over 30mm/hr
What might you see in a plain abdominal X Ray of ulcerative colitis?
- No stool in an inflammed colon
- Mucosal oedema ('thumb printing')
- Toxic megacolon (transverse more than 5.5cm and caecum over 9cm)
What is toxic megacolon?
The inflammation becomes so sever that the tone of the bowel is affected.
What do you see on a colonoscopy of UC?
Confluent inflammation extending from the anal margn to a transition zone
- Loss of vessel pattern
- Granular mucosa
- Contact bleeding
- Pseudopolyps (occur as a result of past inflammation)
- Loss of haustra
- Crypt distortion
What does the histology of crohns disease show?
Only affects mucosal layer
Absence of goblet cells
Crypt distortion and abscess
What are the long term complications of ulcerative colitis?
Increased risk of colorectal cancer (severity of inflammation, duration of disease and the extent of disease)
Extensive colitis (beyond the splenic flexure) requires cancer surveillance after 10 years of disease
What are some of the extra intestinal manifestations of ulcerative colitis?
- Pyoderma gangrenosum
- Erythema nodosum
- Peripheral arthritis
- Stones (oxalate renal stones)
What is primary sclerosing cholangitis?
Chronic inflammatory disease of the biliary tree
Most people are asymptomatic but may have an itch or rigors.
80% have associated IBD (usually UC)
What are the long term complications of PSC?
Median time to death/lover transplant in 10 years
15% of patients get cholangiocarcinoma
Describe the pattern of disease in crohn's disease?
- It can affect any region of the GI tract from the mouth to the anus
- Skip lesions (ie disease free areas)
- Transmural inflammation)
- Per anal disease (recurrent abscesses, pain, fistula leading to leakage, sphincter damage)
25% of people have continuous disease
50% of people have intermittent flares
75% require surgery within 8 - 10 years
Much more aggressive disease than UC
What blood tests would you need if you suspected someone had IBD?
CRP (this correlates well with disease activity)
Platelets (increases with inflammation)
B12 (low as absorbed in terminal ileum)
What investigations do you do to stage the disease activity in crohn's disease?
What would you seen on endoscopy of the bowel affected with crohns diseae?
What is the histology associated with crohn's disease?
Patches of disease then patches of normal mucosa
Inflammation in all layers from mucosa to serosa
What investigations are used to assess the severity of crohns disease?
Barium follow through
Small bowel enema - highly sensitive and specific for disease of the terminal ileum
Small bowel MRI
Technetium labelled white cell scan
What is the main lifestyle advice to give to people with crohn's?
Diet may help symptoms
What is the treatment to induce remission in ulcerative colitis?
Topical 5ASA (mesalazine)
An oral 5ASA can also be added
If there is no improvement within 4 weeks then an oral steroid can be added
If there is still no improvement then oral tacrolimus can be added.
What is the treatment to induce remission in ulcerative colitis if the patient cannot have a 5ASA?
Topical corticosteroid or oral prednisolone
What are the treatments used to maintain remission in people with ulcerative colitis?
1. Topical ASA
2. Oral ASA
3. Azathioprine or mercapturine
What drug do you need to avoid giving with azathiprine?
Give examples of some of the 5 ASA (Aminosalicylates) drugs that are currently used?
How does mesalazine work?
Acts locally on colonic mucosa (full mechanism not entirely understood)
How long and at what dose are steroids usually given to induce remission in UC?
Short course initially a high dose but slowly reducing over 6 - 8 weeks.
What is mechanism of azathioprine?
- A pro drug for mercaptopurine
- Inhibits purine synthesis and therefore less DNA and RNA are formed
- This means that less white blood cells are made which causes immunosuppression
How quickly does azathioprine work?
It has a slow onset of action (16 weeks)
What are the main potential side effects of azathioprine?
Skin cancer (makes you more sensitive to the sun)
Give examples of the anti TNF therapies used in IBD?
Infliximab - IV infusion s
Adalimumab - SC injection
Describe how anti TNF therapy works in IBD?
- TNF is an important part of the body's defence against infection. It is the first cytokine to appear in the blood and it triggers the release of other cytokines such as IL 1 and IL 6.
- Anti TNF therapy is a monoclonal antibody that attaches to TNF and disables causes apoptosis of activated T lymphocytes
- Rapid onset of action
- 30 - 40 % of people will go into remission after a single infusion of anti TNF
What are the risks of anti TNF therapy?
Infection (have to make sure patients don't have current infection/ latent TB)
Increases risk of lymphoma and sold tumours