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