Ulcerative Colitis

Ulcerative colitis is a chronic disease of unknown aetiology in which a part or the whole of the mucosa of the large bowel becomes diffusely inflamed and may ulcerate, as a result of which the patient suffers from diarrhoea which may be bloody.

It is characterised by exacerbations and remissions.

The highest incidence of this disease is in adulthood, although it may occur in childhood. The cause of ulcerative colitis is unknown but genetic, immunological, dietary, and psychological factors have all been implicated.

Epidemiology

This condition may occur at any time from early childhood to late adulthood.

There is an annual incidence of 5-8/100,000 in most communities of Celtic and Anglo-Saxon origin in north-western Europe, North America and New Zealand. The prevalence of symptomatic disease in north-western Europe is 70-150/100,000. This disease is very uncommon in Asia and Africa. As in Crohn's disease, familial clustering may be seen.

Pathological features

• Ulcerative colitis primarily affects the mucosa and the submucosa, with inflammatory cell infiltrate, crypt abscess and ulcer formation. Goblet cells are few in number and frequently depleted of mucus.
• Redundant mucosa between ulcers form pseudopolyps, and the mucosa is friable and bleeding easily on contact.
• There are no skip lesions.
• The rectosigmoid is most commonly involved with 50% of patients having total colonic involvement.
• Chronic disease causes shortening and thickening of the bowel wall with haustral loss.

Clinical features

Ulcerative colitis may be fulminant, chronic, or relapsing. The patient may present dehydrated and/or toxic.

Symptoms include:

• number of stools may vary from 1 or 2 to 20 or 30 per day
• diarrhoea, sometimes bloody; mild abdominal pain in the left iliac fossa; fever; weight loss
• if this condition occurs in infancy or childhood, then the presentation may be of failure to thrive or failure to progress normally into puberty
• in fulminating disease the presentation may be of abdominal distension, catastrophic diarrhoea, fever and collapse

Signs may be as follows:

pallor, dehydration, mouth ulcers, abdominal tenderness.

Associated conditions include:

• erythema nodosum
• pyoderma gangrenosum
• uveitis
• arthritis

Severity

The severity of ulcerative colitis can be assessed on the basis of:

• bowel frequency - less than four motions per day is considered mild, more than six is severe.
• rectal bleeding
• temperature - patients with mild disease are apyrexial, those with severe disease may be higher than 37.8 C.
• haemoglobin of less than 10.5 is considered severe, greater than 11 is mild
• ESR of less than 30mm per hour is mild, greater than this is severe
• tachycardia is related to severity
• low albumin - below 30g per litre implies severe disease

Differential diagnosis

The differential diagnosis is influenced by the presentation, a principal factor being the age.

• Crohn's disease
• infective colitis is often a cause of one episode of colitis which is mislabelled as ulcerative colitis e.g. salmonellosis, shigellosis, Campylobacter, amoebiasis. In the immunosuppressed patient then one must consider opportunistic infections e.g. cytomegalovirus, herpes virus, Cryptosporidium, Mycobacterium avium intracellulare.
• colonic carcinoma, adenoma - diagnosed on endoscopy, particularly important in the elderly
• diverticulitis - not in childhood
• irritable bowel disease, which would tend to occur in the young, and has early morning explosiveness, not tending to be bothered at night.
• ischaemic colitis - these patients may have a history of vascular disease with sudden onset of pain, and thumb printing on plain abdominal radiography or barium enema. It does not occur in childhood.
• post-radiation colitis, the diagnosis of which is based on the history

Investigations

• FBC - anaemia due to blood loss; leukocytosis
• ESR - increased; correlates with active disease
• CRP - raised; but less so than in Crohn's disease
• biochemistry - in active disease, biochemical abnormalities may include hypokalaemia, hyponatraemia, hypomagnesaemia, hypocalcaemia, and hyoalbuminaemia. Abnormal LFTs due to associated chronic active hepatitis - increased ALT - or sclerosing cholangitis - increased alkaline phosphatase
• ANCA - found in HLA-DR2 associated form of ulcerative colitis
• Radiology:

·         plain abdominal x-ray - excludes toxic dilatation, which is more than 5.5 cm in diameter in adults

·         barium enema:

o        diagnosis of extent and severity of the disease

o        procedure is contraindicated in those patients at risk of a toxic dilatation

• rectal biopsy - taken at sigmoidoscopy
• colonoscopy - this is contraindicated in those patients at risk of toxic dilatation. Allows multiple biopsies to be taken throughout the colon and delineation of the extent and activity of the disease
• white cell scan - allows imaging in severe disease

• molecular biology - a high intensity of CD44v6 and v3 epitope expression on crypt epithelial cells in patients with UC has been noted. This observation may have diagnostic potential in distinguishing UC from Crohn's

Diagnosis

Careful history and examination is, of course, very important for the diagnosis of ulcerative colitis. The hallmark is bloody diarrhoea with mucus, usually of gradual onset, but it can be abrupt.

The diagnosis of ulcerative colitis is based on:

• exclusion of other causes of diarrhoea like bacillary or amoebic dysentry
• colonoscopy and biopsy - histological characteristics, and endoscopic features
• differentiation from Crohn's disease - this may be very difficult:
• ANCA positivity associated with forms of ulcerative colitis
• increased expression of CD44v6 and CD44v3 variants in the colonic mucosa of patients with ulcerative colitis has been described and may have diagnostic potential in differentiating ulcerative colitis and Crohn's disease. There is absence of CD44v6 expression from normal colonic mucosa, but CD44v6 and CD44v3 have been identified in colorectal tumours.

Management

There have been massive improvements in the management of ulcerative colitis in the past 40 or 50 years, as evidenced by the death rates in severe attacks:

• before 1952, 45%
• now, 1 to 2 %

The management has been improved by:

• corticosteroids
• better understanding of fluid balance and electrolytes in severely ill patients
• better understanding of indicators of severity of the disease

Surgical management

• Surgery is required in 20% of patients with ulcerative colitis.
• The quality of life after surgery is excellent and a colectomy eliminates the need for continuous medical therapy and the need for cancer surveillance.
• Most extraintestinal symptoms of UC will resolve after a colectomy. The exceptions to this are sclerosing cholangitis and arthritis. Note also that growth retardation is reversed if a colectomy is performed before puberty.

Indications

With ulcerative colitis, emergency surgery is indicated for:

• haemorrhage
• perforation
• toxic megacolon
• severe flares which have failed course of high dose steroids, complete bowel rest and intravenous feeding
• development of colonic carcinoma

Elective surgery is indicated for:

• intractable symptoms
• long-standing active disease which increases the risk of carcinoma

Principles of surgery

Removal of the entire large bowel, by definition, is curative in ulcerative colitis.

Alternatives include a panproctocolectomy and terminal ileostomy, and total colectomy and ileo-rectal anastomosis.

• panproctocolectomy and terminal ileostomy:
• the whole colon is removed from the caecum to the anus
• this procedure necessitates the construction of a permanent ileostomy
• total colectomy and ileo-rectal anastomosis:
• in this procedure the colon is removed but the rectal stump is left in situ.
• the terminal ileum may be re-anastomosed to it, either at the initial operation or as a secondary procedure.
• it is possible to fashion the terminal ileum into a pouch - Park's pouch - to form a reservoir above the rectal stump. There is a risk recurrence of disease in the rectal stump. Thus the rectal mucosa is first stripped and the pouch anastomosed to the dentate line.

Cancer surveillance in Ulcerative Colitis

There is an increased risk of developing colorectal carcinoma in patients with UC. The risk of development of cancer is dependent on the duration and the extent of the disease.

If the patient has a pancolitis then:

• after 10 years risk is 1
• after 20 years risk is 13%
• after 30 years risk is 34%

It is conjectured that neoplasms are preceded by initially mild and later severe dysplasia of the colonic epithelium. Surveillance in the form of colonoscopy with multiple biopsies every 18-24 months is designed to identify such premalignant changes.

Complications/Associations

Local complications:

• haemorrhage
• malnutrition
• electrolyte imbalance
• toxic megacolon
• stricture formation - rare
• fistula formation - rare
• perforation
• increased risk of malignancy - lymphoma, carcinoma

General:

• weight loss
• anaemia
• hypoproteinaemia
• arthropathy - tends to affect large weight-bearing joints
• liver associations:
• primary sclerosing cholangitis
• fatty liver
• non-specific hepatitis
• pericholangitis
• chronic active hepatitis
• bile duct carcinoma
• sacro-iliitis and ankylosing spondylitis
• pyoderma gangrenosum
• erythema nodosum
• anterior uveitis
• episcleritis
• carcinoma of the bile ducts - rare

Note that gallstones are associated with Crohn's disease but not ulcerative colitis.

Prognosis

• a colectomy is curative
• 70% of patients with untreated UC relapse annually
• there is a 1% risk of the development of colonic cancer if someone has the disease for 10 years; in most UK centres, patients with extensive UC of 10 years' duration are offered colonoscopy every 1-2 years in an effort to prevent colonic cancer by taking multiple biopsies to look for mucosal dysplasia and to offer colectomy if appropriate, or to detect cancer at a curable stage
• there is a substantial variation in severity, extent and responsiveness, together with extra-intestinal and multiple intestinal manifestations
• life-expectancy is similar to that of the general population
• patients with well-controlled distal UC can be followed up routinely in primary care (will require a blood count and liver function test every 6-12 months, and referral for colonoscopy at 8-10 years to reassess disease extent)

COURTESY:esurgicalhandbook.com

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