Ulcerative colitis

Aetiology

The cause of ulcerative colitis is unknown; its prevalence among first-degree relatives of patients is 15 times that of the general population but there is no clear Mendelian pattern of inheritance. In spite of intensive bacteriological studies, no organisms or group of organisms can be incriminated. Relapse of colitis has, however, been reported in association with bacterial dysenteries. Some cases are allergic to milk protein. Smoking seems to have a protective effect and there have been anecdotal reports of remission of the disease with smoking or the use of nicotine chewing gum. Patients often comment that relapses are associated with periods of stress at home or at work, but personality and psychiatric profiles are the same as the normal population.

There remain three main hypotheses, none of which has been proved:

1. a mucosal immunological reaction;

2. a weakened mucous barrier;

3. defective mucosal metabolism of butyrates.

Epidemiology

There are 10—15 new cases per 100 000 population a year in the UK. The disease has been rare in Eastern populations hut is now being reported more commonly, suggesting an envi­ronmental cause that has developed as a result of an increas­ing ‘westernisation’ of diet and/or social habits and better diagnostic facilities. The sex ratio is equal; it is uncommon before the age of 10 and most patients are between the ages of 20 and 40 at diagnosis.

Pathology

In 95 per cent of cases the disease starts in the rectum and spreads proximally. When the ileocaecal valve is incompetent, retrograde (backwash) ileitis involving the last 30 cm of the ileum is likely to occur. It is a nonspecific inflammatory disease, primarily affecting the mucosa and superficial sub­mucosa, and only in severe disease are the deeper layers of the intestinal wall affected. There are multiple minute ulcers, and microscopic evidence proves that the ulceration is almost always more severe and extensive than the gross appearance indicates. When the disease is chronic, inflammatory polyps (pseudopolyps) occur in up to 20 per cent of cases and may be numerous. They result from previous episodes of ulceration heaving islands of spared mucosa which will remain prominent when the adjacent mucosa heals. In severe fulminant colitis a section of the colon, usually the transverse colon, may become acutely dilated and the intestinal wall then becomes extremely thin and may perforate (‘toxic megacolon’). On microscopic investigation there is an increase of inflammatory cells in the lamina propia, the walls of crypts are infiltrated by inflammatory cells and there are crypt abscesses. There is depletion of goblet cell mucin. The crypts are reduced in number and appear to be atrophic and irregularly spaced. With time these changes become severe and precancerous changes can develop (r~ severe dysplasia or carcinoma in situ).

Symptoms

The first symptom is watery or bloody diarrhoea; there may be a rectal discharge of mucus which is either blood stained or purulent. Pain as an early symptom is unusual. In most cases the disease is chronic and characterised by relapses and remissions. In general, a bad prognosis is indicated by (1) a severe initial attack, (2) disease involving the whole colon and (3) increasing age, especially after 60 years. If the disease remains confined to the left colon the outlook is better.

Proctitis

Inflammation confined to the rectum accounts for about 25 per cent of all cases. As most of the colon is healthy the stool is formed or semi-formed and the patient is often severely troubled by tenesmus and urgency. The risk of cancer in these cases is low. In 5—10 per cent there is spread to involve the rest of the colon.

Left-sided and total colitis (Fig. 57.20)

Diarrhoea usually implies that there is active disease proxi­mal to the rectum. Approximately 15 per cent of patients have left-sided colitis, and 25 per cent have total colitis extending beyond the midtransverse colon. The clinical pattern is one of recurrent severe attacks of bloody diarrhoea up to 20 times a day, dehydration and fluid electrolyte losses. Anaemia and hypoproteinaemia are common.

Disease severity

Disease severity can be graded as:

1.mild — rectal bleeding or diarrhoea with four or fewer motions per day and the absence of systemic signs of disease;

2. moderate — more than four motions per day but no systemic signs of illness;

3. severe — more than four motions a day together with one or more signs of systemic illness: fever over 37.50C, tachy­cardia more than 90/minute, hypoalbuminaemia less than 30 g/litre, weight loss more than 3 kg.

Complications of severe disease

Fulminating colitis and toxic dilatation (megacolon) (Fig. 57.21).

 Patients with severe disease should he admitted to hospital. Dilatation should he suspected in patients with active colitis who develop severe abdominal pain. It is an indication that inflammation has gone through all the muscle layers of the colon. The diagnosis is confirmed by the presence on a plain abdominal radiograph of the colon with a diameter more than 6 cm. The condition must be differentiated from dysentery, typhoid and amoebic colitis. Plain abdominal radiographs should he obtained daily in patients with severe colitis and a progressive increase in diameter in spite of medical therapy is an indication for surgery (Fig. 57.22).

Perforation. Colonic perforation in ulcerative colitis is a grave complication with a mortality rate of 50 per cent or more. Steroids may mask the physical signs. Perforation can sometimes occur without toxic dilatation. Generally patients with severe attacks should be managed so that they do not develop these complications.

Severe haemorrhage. Severe rectal bleeding is uncommon and may occasionally require transfusion and rarely surgery.

Investigations

A plain abdominal film can often show the severity of disease. Faeces are only present in parts of the colon that are normal or only mildly inflamed. Mucosal islands can sometimes be seen and have been mentioned. Small bowel loops in the right lower quadrant may be a sign of severe disease.

Barium enema

The principal signs are (Fig. 57.23):

  loss of haustration, especially in the distal colon;

  mucosal changes caused by granularity;

  pseudopolyps;

  in chronic cases, a narrow contracted colon.

In some centres an instant enema is used with a water-soluble medium for contrast instead of barium and no bowel preparation to avoid aggravating any underlying colitis (Fig. 57.24).

Sigmoidoscopy

Sigmoidoscopy is essential for diagnosis of early cases and mild disease not showing up on a barium enema. The initial findings are those of proctitis, the mucosa is hyperaemic, bleeds on touch and there may be a pus-like exudate. Later tiny ulcers may be seen and appear to coalesce. This is different from the picture of amoebic dysentery where there are large deep ulcers with intervening normal mucosa.

Colonoscopy and biopsy

This has an important place in management:

1. to establish the extent of inflammation;

2. to distinguish between ulcerative colitis and Crohn’s colitis;

3. to monitor response to treatment;

4. to assess long-standing cases for malignant change.

Although it may occasionally be helpful, colonoscopy is not usually used in acute cases for fear of aggravating the disease or perforation.

The cancer risk in colitis

Although this is an important complication the overall risk is only about 3.5 per cent. It is much less in early cases but increases with duration of disease. Thus, after 20 years of colitis the risk may be as much as 12 per cent. Carcinoma is more likely to occur where the whole colon is involved and where the disease started in early life (Fig. 57.25). Carcinomatous change, often atypical and high grade, may occur at many sites at once. The colon is involved rather than the rectum and the maximal incidence is during the fourth decade.

The golden rule is that, when the disease has been present for 10 years or more, regular colonoscopic checks must be carried out, even if the disease is clinically quiescent. If on biopsy there is severe epithelial dysplasia, surgery is indicated. Annual colonoscopy and biopsy is then part of cancer surveillance. In the rare cases with a fibrous stricture these should be examined especially carefully for the presence of an underlying carcinoma.

Extraintestinal manifestations

Arthritis occurs in around 15 per cent of patients and is of the large joint polyarthropathy type, affecting knees, ankles, elbows and wrists. Sacroileitis and ankylosing spondylitis are 20 times more common in patients with ulcerative colitis.

Skin lesions: erythema nodosum, pyoderma gangrenosum or aphthous ulceration.

Eye problems:    iritis.

Liver disease: sclerosing cholangitis has been reported in up to 70 per cent of cases. Diagnosis is by ERCP which demonstrates the characteristic alternating stricturing and bleeding of the intrahepatic and extrahepatic ducts.

Bile duct cancer is a rare complication and colectomy does not appear to reduce the risk of subsequent bile duct cancer or sclerosing cholangitis.

Treatment

Medical treatment of an acute attack

Corticosteroids are the most useful drugs and can be given either locally for inflammation of the rectum or systemically when the disease is more extensive. Sulphasalazine and other 5-aminosalicylic acid (5-ASA) derivates, for example, mesalazine and olsalazine, can be given both topically and systemically.

Their main function is in maintaining remission rather than treating an acute attack. Nonspecific antidiarrhoeal agents have no place in the routine management of ulcerative colitis.

Mild attacks

Patients with a mild attack and limited disease will usually respond to rectally administered steroids. In those with more extensive disease, oral prednisolone 20—40 mg/day is given over a 3—4-week period. Sulphasalazine 1 g three times a day or one of the newer 5-ASA compounds should be given concurrently.

Moderate attacks

These patients should be treated with oral prednisolone 40 mg/day, twice daily steroid enemas and 5-ASA. Failure to achieve remission as an out-patient is an indication for admission.

Severe attacks

These patients must be regarded as medical emergencies and require immediate admission to hospital. Their appearance is often misleading, and they must be examined at least twice a day with particular reference to the presence of signs of peritonism. Their abdominal girth is measured and liver dullness should be percussed regularly. A plain abdominal radiograph is taken daily and inspected for dilatation of the transverse colon of more than 5.5 cm. The presence of mucosal islands on plain radiographs (see Fig. 57.22), increasing colonic diameter or a sudden increase in pulse and temperature may indicate a colonic perforation. A stool chart helps in the assessment of response to therapy, and careful medical/surgical joint man­agement is essential. Fluid and electrolyte balance is main­tained, anaemia is corrected and adequate nutrition provided, sometimes in severe cases with intravenous nutrition. The patient is maintained nil by mouth and treated with intravenous hydrocortisone 100—200 mg four times daily. This can be supplemented with a rectal infusion of prednisolone. There is no evidence that antibiotics modify the course of a severe attack. Some patients are treated with azathioprine or cyclosporin A to induce remission, If there is failure to gain an improvement within 5—7 days then surgery must be seriously considered. Prolonged high-dose intravenous steroid therapy is fraught with danger. Patients who have had weeks of treatment, during which the colonic wall has become friable and disintegrates at laparotomy, are now fortunately rare.

Indications for surgery

The risk of colectomy is 20 per cent overall, ranging from 5 per cent in those patients with proctitis to 50 per cent in those patients with a very severe attack:

  severe or fulminating disease failing to respond to medical therapy;

  chronic disease with anaemia, frequent stools, urgency and tenesmus;

  steroid-dependent disease: here the disease is not severe but remission cannot be maintained without substantial doses of steroids;

  the risk of neoplastic change: patients who on review colonoscopy have severe dysplasia;

extraintestinal manifestations;

  rarely, severe haemorrhage or stenosis causing obstruction.

Operations

I. In the emergency situation the ‘first-aid procedure’ is a total abdominal colectomy and ileostomy. The rectum can either he brought out at the lower end of the wound as a mucous fistula or closed just beneath the skin. This has the advantage that the patient recovers quickly, the histology of the resected colon can he checked, and restorative surgery can be contemplated at a later date when the patient is no longer on steroids and in optimal nutritional condition. The alternative, division of the rectum below the sacral promontory, can result in breakdown and pelvic abscess, and makes subsequent identification of the stump more difficult.

2.       Proctocolectomy and ileostomy: this is the procedure associated with the least compilcation rate. The patient is left with a permanent ileostomy There is, however, a 20 per cent long-term risk of adhesion obstruction, and 5—10 per cent of the perineal wounds are very slow to heal. The late result will be a chronic perineal sinus which may require repeated currettage or excision. The obvious disadvantage is an ileostomy and although many patients cope remarkably well there is a psychological and social ‘cost’.

Rectal and anal dissection. Refinements of the procedure have included a close rectal dissection to minimise damage to the nervi erigentis and hence erectile dysfunction which may occur in 0.5—2 per cent, and inter sphincteric excision of the anus which results in a smaller perineal wound and fewer healing problems.

3. Restorative proctocolectomy with an ileoanal pouch (Parks). In this operation a pouch or reservoir is made out of ileum (Fig. 57.26) as a substitute for the rectum and sewn or stapled to the anal canal. Various pouch designs have been described, hut the J is the most popular and the most easily made using staplers (Fig. 57.27). There is some controversy over the correct technique for ileoanal anastomosis. In the earliest operations, the mucosa from the dentate line up to midrectum was stripped off the underlying muscle, but it is now known that a long muscle cuff is not needed. A mucosectomv of the upper anal canal with an anastomosis at the dentate line is claimed to remove all of the at risk mucosa and any problem of subsequent cancer. It may also result in imperfect continence with nocturnal seepage. The alternative is a double stapled anastomosis to the top of the anal canal preserving the upper anal canal mucosa. Continence appears to be better, but the theoretical risk of leaving inflamed mucosa remains.

The procedure can he carried out in one, two or three stages. In selected cases a covering loop ileostomy is omitted hut is usually used. Complications include pelvic sepsis — usually resulting from a leak of the ileoanal anastomosis, small bowel obstruction and pouch vaginal fistula. Frequency of evacuation is determined by pouch volume, completeness of emptying, reservoir inflammation and intrinsic small bowel motility, but can be between three and six evacuations daily. Although associated with a higher complication rate, it is rapidly becoming the operation of choice in younger patients, avoiding a permanent ileostomy. About 20 per cent of patients have an episode of pouchitis, that is, inflammation of the reservoir, at some time. It usually responds to treatment with metronidazole.

4.       Colectomy and ileorectal anastomosis: if there is minimal rectal inflammation this can occasionally he used; it has largely been superseded by restorative proctocolectomy.

5.       ileostomy with a continent intra-abdominal pouch (Kock’s proce­dure). A reservoir is made of ileum and just beyond this a spout is made by inverting the efferent ileum into itself to give a continent valve just below skin level. The pouch is emptied by the patient inserting a catheter through the valve; now rarely used.

Ileostomy

End ileostomy (Brooke). In those patients with a permanent ileostomy there must be scrupulous attention to detail during the operation to ensure that the patient has a good functional result. The position of the ileostomy should be carefully chosen by the patient with the help of a stoma care nursing specialist. The ileum is normally brought through the lateral edge of the rectus abdominis muscle. The use of a spout (Fig. 57.28) was originally described by Bryan Brooke and it should project some 4 cm from the skin surface. A disposable appliance is placed over the ileostomy so that it is a snug fit at skin level.

ileostomy care

During the first few postoperative days, fluid and electrolyte balance must he adjusted with great care. There may he an ‘ileostomy flux’ while the ileum adapts to the loss of the colon, and the fluid losses can amount to 4 or 5 litres/day. The stools thicken in a few weeks and are semisolid in a few months. The help, skill and advice of the stoma care nursing specialist are essential. Modern appliances have transformed stoma care and skin problems are unusual (Fig. 57.29).

Complications of an ileostomy include prolapse, retraction, stenosis, bleeding and paraileostomy hernia.Loop ileostomy. This is often used to defunction a pouch ileoanal procedure or even a low anterior resection. A knuck­le of ileum is pulled out through a skin trephine in the right iliac fossa. An incision is made in the distal part of the knuck­le and this is then pulled over the top of the more proximal part to create a spout on the proximal side of the loop with a flush distal side still in continuity. This allows near-perfect defunction, but also the possibility of restoration of continuity by taking down the spout and reanastomosing the partially divided ileum.