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IBD - Inflammatory Bowel Disease

Summary
Crohn’s
UC
Incidence
5-10 per 100 000
10 to 20 per 100 000
Mean age of onset
26
Can also present in children – failure to thrive
and also in those in their 60’s
34
Male: Female
1.2 : 1
1 : 1.2
Affects
Any part of GIt, most commonly the terminal ileum. Also commonly affects the rectum, but not the colon
Only colon, usually more distal regions are worse affected
Mortality
Low
Lower
Surgery required in
50-80%
20%
Skip lesions
Yes
No
Mucosal Layers
Deeper
More superficial
Complications
Fistula, abscess, stricture. Most commonly the fistulae come from the anus to the peri-anal region and the produce pus
Rare. Toxic megacolon
pANCA
Negative
Positive
Race
Most common in Caucasians
Most common in Caucasians
Protective factors
High residue, low sugar diet, relatives with Crohn’s means you have an INCREASED RISK
Smoking, appendicectomy, high reside low sugar diet
Pathology
Thought to be very similar in both diseases. In genetically susceptible individuals there is an adverse reaction to bacterial lipopolysaccharide. Normally the reaction against this is self limiting, but in IBD patients once the inflammation starts it may not stop. Thus ultimately it is a kind of autoimmune disease – and the inflammation ends up damaging the gut wall. The diseases follow a relapsing and remising course.
Symptoms
Left iliac fossa mass/pain – this is present even when there is no abscess, abdominal discomfort, blood in the stools, vitamin B12 and iron deficiencies – Crohn’s commonly affects the small intestine and thus can cause malabsorption.
Diarrhoea due to excess mucus production. often also contains blood. Abdominal discomfort, bloating . symptoms usually less severe than Crohn’s
Extra-intestinal symptoms
These are generally the same for both conditions. They include; large joint arthritis, irisitis (like conjunctivitis, but worse), erythema nodosum (red rashes on the shins, more common in UC), ulcers on mucous membranes (mouth and vagina – more common in Crohn’s), cholangitis, pyoderma gangrenosum – this is nasty dead black pussy necrotic tissue. Most commonly found on the legs and around the stoma, renal stones, gallstones, fatty liver, fat wrapping – only occurs in Crohn’s – this is where the messenetric fat spreads around the intestine
Crohn’s disease is associated with an increased risk of bowel cancer –this is typically adenocarcinoma of the distal ileum
Signs
The acute presentation may be mistaken for appendicitis. However, a good history may reveal some facts pointing to a background acute disease.
May be few in mild disease.may include weight loss and malaise. In an acute attack there can be fever, malaise, iron def anaemia, raised WBC, platelets and ESR, hypoalbuminaemia
Barium swallow
This is the most useful test. It can show areas of stricture, shortening of small bowel, fistulas and abscesses
PR
Blood
CT
Will shows areas of wall thickening, strictures and abscesses
CT
Thickened bowel wall
Colonoscopy
Not that useful but can biopsy. Also may help you differentiate pseudopolyps from true polyps
Barium enema
Reduced haustral folds due to fibrosis
CLUBBING!
Treatment
Cessation of smoking is enough to induce remission in many patients. Unlike UC treatment is not given to maintain remission, only to initiate it. 5-ASA compounds are not used
Basically the same as UC, without the 5-ASA. Immunosuppresants used in severe disease 80% of Crohn’s patients will end up having surgery. Many require B12 and iron supplements
Low residue diets and low fat diets can help reduce symptoms. Patients may need to be given supplements of the fat soluble vitamins (A D E K). patients are often given antibiotics to reduce the intestinal flora and diarrhoea – metronidazole
Infliximab is used in patients that don’t respond to other types of treatment. 70% of Crohn’s patients will respond to it. It is particularly useful in perianal disease
Mild disease: 5-ASA
Moderate disease: steroid to initiate remission, then 5-ASA
Severe disease: trial steroid for 5-7 days. If no remission, then operate immediately. Try to maintain remission with 5-ASA, if not then immunosuppressant may be used.
Steroids are often given as a rectal foam
In 10% of cases it is not possible to differentiate fromCrohn’s or UC, and thus these patients are said to have intermediate colitis.
Drugs
Drug
Mechanism
Side-effects
Info
Cyclosporin
Immunosuppressant. Inhibits T cell division
Nephrotoxicity, hypertension, hepatic dysfunction, tremor, headache, anorexia, nausea, vomiting, gum hypertrophy, excessive hair growth
Azathioprine
Immunosuppressant. Inhibits purine synthesis. reduces the turnover rate of quickly dividing cells
Nausea, vomiting skin rashes, and other similar to other immunosupressants.
Side effects tend to reduce after 6 weeks
Methotrexate
Immunosuppressant. Inhibits the metabolism of folic acid. reduces the turnover rate of quickly dividing cells
Similar to above
Not licensed for Crohn’s
Sulfasalazine*
(ASA)
Not really known. Thought to trap free radicals released in the inflammatory process
Headache, nausea, vomiting, oligpspermia (low semen volume, but not reduced sperm count), rashes, nephrotoxicity
Can both initiate and maintain remission
Infliximab
Monoclonal antibody – this is an antibody to TNFα. You give loads of it, and it stops TNF alpha binding to its  binding site, and thus reduces inflammation
Not licensed for UC
*this is actually a combination of an ASA compound and a sulphapyridine. The sulphapyridine makes the druh pH sensitive, thus it is activated at the right place in the bowel (i.e. the colon).
Surgery
Crohn’s
Bowel resection – patients will often have to have several resections during their lifetime. Thus when you operate, you should be as conservative as possible. you should remove the affected area, and 2cm either side. Big wide resections do not decrease the recurrence rate. you should try to avoid small bowel syndrome by resecting too large an area
Stricturoplasty
In the case of a severe stricture, you can cut the bowel lengthways along the stricture, and then sew it back together to widen the strictured part.
Surgery is generally reserved for stricutres, fistulas, disease that does not respond to drug treatments. Abscesses are generally treated by percutaneous drainage and not by surgery
Fistulas can exist between parts of the bowel, e.g. between the small and large intestines. These can affect absorption
After surgery many patients will have a massive initial improvement in symptoms.
UC
The whole colon has to be removed, otherwise the disease will return in the part of the colon you have not taken out. You can either have a permanent ileostomy (rare) or a temporary one (restorative protocolectomy). In the restorative surgery, the colon is removed (1% chance of sexual dysfunction in males) and the end of the ileum is then folded over one itself to create a ‘pouch’. This pouch becomes the rectum. It requires two separate operations. One to create the pouch, the other to connect the pouch to the anus. It can be done in one, but this increases the risk of sepsis. After the operation, patients will have to empty the bowel about 5-6 times a day, but there will not usually be urgency. There are often n other symptoms, and thus for many patients, this is better than the symptoms they experiences during exacerbations of UC. Most patients will take anti-diarrhoeal agents at some point.
Toxic megacolon – this is where the colon becomes massively distended. It can induce tachycardia and shock, and may also present with fever. It is a medical emergency, and if it does not respolve, will require surgery to prevent perforation

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