Chronic inflammatory disorders of the bowel

Question 1

Chronic inflammatory disorders of the bowel

Answer 1

• Substantial inflammation in any part of the small or large bowel usually presents with diarrhoea (i.e. frequent passage of loose stools).
• When inflammation affects the large bowel, the diarrhoea often contains blood.
• Chronic diarrhoea is defined as lasting for longer than 6 weeks, different from the acute diarrhoea of gastroenteritis which is usually of viral origin or related to food poisoning and is usually self-limiting, though often fatal in infants in the developing world.

Question 2

Ulcerative colitis

Answer 2

• Ulcerative colitis is an inflammatory disorder of the mucosa and submucosa of the large bowel only
• characterised by recurrent acute exacerbations and intervening periods of quiescence or chronic low-grade activity.
• disease always involves the rectum but often extends proximally in continuity to involve a variable length of colon.
• In 20% of cases (but only those with pancolitis, i.e. colitis involving the whole large bowel), the distal end of the ileum becomes secondarily affected; this is described as backwash ileitis

Question 3

Pathophysiology of ulcerative colitis

Answer 3

• colonic mucosa becomes acutely inflamed. Neutrophils accumulate in the lamina propria and within the tubular colonic glands to form small, highly characteristic crypt abscesses
• Sloughing of the overlying mucosa produces small superficial ulcers. If the inflammatory process persists, the ulcers coalesce into extensive areas of irregular ulceration
• Residual islands of intact but oedematous mucosa project into the bowel lumen; these inflammatory lesions are called pseudopolyps
• inflammation is usually confined to the mucosa and submucosa, only extending into the muscular wall and peritoneal surface in fulminating colitis.
• The colonic glands show a marked reduction in the number of mucin-secreting goblet cells, histologically termed ‘goblet cell depletion’.

Question 4

Clinical features of ulcerative colitis

Answer 4

• Acute inflammatory attacks are marked by loose blood-stained stools streaked with mucus.
• results from inflammation of recto-sigmoid colonic mucosa
• patient may pass 20 or more loose stools a day, each time preceded by cramping abdominal pain.
• may progress to the severe form of fulminant colitis; the patient may become prostrated by dehydration
• Occasionally, the colon dilates massively and patchy necrosis eventually occurs. The patient is systemically ill with high fever, marked tachycardia and dehydration. This process, known as toxic megacolon

Question 5

Systemic manifestations of ulcerative colitis

Answer 5

Weight loss:

• Frequent during exacerbations

Anaemia:

• Typically chronic and non-specific (normochromic, normocytic)

Arthropathy:

• Sacroiliitis/ankylosing spondylitis or rheumatoid-like arthritis, especially of large joints (approximately 20% of cases)

Uveitis and iritis:

• Painful red eye or eyes (approximately 10%)

Skin lesions:

• Erythema nodosum, i.e. tender red nodules on the shins (uncommon), pyoderma gangrenosum, i.e. purulent skin ulcers (rare)

Sclerosing cholangitis:

• Progressive fibrosis of intrahepatic biliary system leading to cirrhosis, progressive liver failure, jaundice and eventually death (rare)

Question 6

Clinical examination and investigation of suspected ulcerative colitis

Answer 6

• history of several weeks of frequent loose stools, later streaked with blood and mucus
• often starts with an attack of gastroenteritis or traveller’s diarrhoea which fails to settle. There is sometimes a history of non-GI symptoms such as arthropathy or uveitis
• General examination often reveals anaemia but abdominal examination is usually unremarkable
• Rectal examination, followed by proctoscopy and sigmoidoscopy, is mandatory to palpate, inspect and, if necessary, biopsy the rectal mucosa.
• three separate fresh stool samples should be analysed to exclude bacterial or parasitic causes or cytomegalovirus

Question 7

Management of ulcerative colitis

Answer 7

Local corticosteroid or 5-ASA preparations (suppositories, foam or liquid enema):

• Employed in cases of left-sided active disease

Systemic corticosteroids:

• Suppress moderate or severe exacerbations (oral or intravenous administration according to severity of disease)

Oral (or sometimes rectal) aminosalicylate preparations, e.g. sulfasalazine, mesalazine (Asacol or Pentasa) or olsalazine

• Long-term maintenance therapy to minimise relapse

Surgical removal of the colon

• Emergency operation: incipient or actual perforation, serious haemorrhage, failure of fulminant colitis to improve on medical treatment
• Elective operation: failure of medical treatment, risk of malignancy

Question 8

Surgery for ulcerative colitis (1)

Answer 8

Colectomy may be needed in the following:

• Urgent treatment of fulminant cases which fail to respond to intensive medical treatment
• Acute cases which progress to toxic megacolon, perforation or major haemorrhage
• Patients with chronic disabling symptoms of intractable diarrhoea with urgency, recurring anaemia and failure to maintain adequate weight and nutrition
• Children with failure to thrive and retardation of growth
• Patients with longstanding colitis who develop dysplasia or malignancy

Question 9

Surgery for ulcerative colitis (2)

Answer 9

Surgery for ulcerative colitis requires removal of the entire large bowel and is curative. There are three main surgical options:

• Subtotal colectomy with ileostomy is the safest operation in the emergency situation when the patient is sick and on high-dose corticosteroids
• Proctocolectomy with permanent ileostomy (includes removal of rectum) is generally recommended for elderly patients in whom sphincter-preserving procedures are inadvisable
• Restorative proctocolectomy (ileo-anal pouch, Parks’ pouch) is a sphincter-preserving operation which avoids a permanent ileostomy
  
  • The entire colon and rectal mucosa is excised and a pouch reservoir is fashioned from a loop of terminal ileum.
  • The pouch is brought into the pelvis and anastomosed to the upper anal canal.
  • Many patients have excellent continence and can evacuate their bowels in the normal way