Case 8.3 – IBD (UC & Crohn's)

History & Examination Approach:

• Routine GIT history - detailed bowel history, dietary triggers, family history, smoking status
• GIT examination - abdominal examination, perianal examination
• Look for (uncommon) extra-intestinal manifestations of IBD:
  • Ocular: conjunctivitis, iritis, uveitis, iridocyclitis, episcleritis
  • Skin: pyoderma gangrenosum, erythema nodosum multiforme
  • Joint: ankylosing spondylitis, hypertrophic osteoarthropathy, arthritides
  • Biliary manifestations: sclerosing cholangitis, pericholangitis, granulomatous hepatitis
  • Other: vasculitis and aphthous stomatitis

Investigations for IBD:

• CT with oral contrast - helpful for small bowel disease, as well as colonic disease in sick patient
• Colonoscopy with biopsy - diagnoses ulcerative colitis as well as Crohn's colitis/ileitis
• Note: There are no laboratory studies specific for the diagnosis of Crohn's disease

Additional laboratory investigations to consider:

• FBC (full blood count) - assess for anaemia, leucocytosis
• CRP & ESR - markers of inflammation
• U&E - electrolyte disturbances from diarrhoea
• Albumin - nutritional status
• Stool cultures - exclude infectious causes
• Faecal calprotectin - marker of intestinal inflammation

Comparison of Ulcerative Colitis and Crohn's Disease:

Feature	Ulcerative Colitis	Crohn's Disease
SYMPTOMS & SIGNS
Diarrhoea	Both UC and Crohn's	Both UC and Crohn's
Perianal fistulas	Rare	Common
Strictures or obstruction	Uncommon	Common
Perforation	Both UC and Crohn's	Both UC and Crohn's
PATTERN OF DEVELOPMENT
Rectum	Always involved	Often normal
Terminal ileum	Normal	Diseased in majority of patients
Distribution	Continuous	Segmented, skip lesions
Megacolon	Can occur	Less common
GROSS & MICROSCOPIC APPEARANCE
Gross appearance	Friable, bleeding granular exudates, pseudo-polyps, isolated ulcers	Linear ulcers, transverse fissures, cobble-stoning, thickening, strictures
Microscopic appearance	Inflamed submucosa & mucosa, crypt abscesses; fibrosis uncommon	Transmural inflammation, granulomas, fibrosis
RADIOLOGIC IMAGING FINDINGS
Radiologic features	Lead-pipe, foreshortening, continuous, concentric	String sign in small bowel; segmental, asymmetry, internal fistulae
COURSE OF ILLNESS
Natural history (variable)	Exacerbations, remissions, dramatic flare-ups	Exacerbations, remissions, chronic, indolent
RESPONSE TO MEDICAL/SURGICAL TREATMENT
Medical treatment	Initial response high (> 80%)	Response less predictable
Surgical treatment	Curative	Useful for complications
Recurrence after surgery	No	Common
RISK OF MALIGNANCY
Cancer risk	Approximately 10% per decade after onset of symptoms. Recommend commencing surveillance at 10 years since onset of symptoms.

Medical Therapy for IBD:

Medical therapy is usually the initial treatment. It is successful in approximately 80% of cases.

Treatment by Disease Severity:

Mild Disease:

• Antidiarrhoeal agents that slow gut transit (e.g., loperamide)
• Bulking agents (psyllium seed products) that result in semiformed, less watery stools
• Treatment is primarily symptomatic

Moderate Disease:

• Sulfasalazine or mesalamine-based preparations should be tried
• Induce remission in approximately half of all patients initially

Severe Disease:

• Steroid administration - most patients respond dramatically
• Unfortunately, because of severe side effects, the dose is tapered and minimised whenever possible
• Azathioprine and related compounds are useful, but take some time to work
• Usually introduced when there would be ongoing need for steroids

Biologic Therapy:

• Anti-tumour necrosis factor (anti-TNF) monoclonal antibody may be used in treating patients with Crohn's disease, especially in the presence of fistulae
• More effective in patients with Crohn's disease of the small bowel
• Patients with primary colonic involvement also have significant response rates

Supportive Therapy:

• Physical and emotional support is important

Management of Major Complications:

Major complications include: toxic megacolon, colonic perforation, massive haemorrhage, serious anorectal complications, and carcinoma development after years of disease.

Initial therapy for toxic megacolon:

• Aggressive medical care
• Gastric decompression
• Antibiotics
• Intravenous administration of fluid and electrolyte
• Hyperalimentation
• Elimination of all other medications, specifically anticholinergics
• Close observation

Surgical Therapy for IBD:

Indications for Surgery:

• When medical therapy fails
• Surgically treatable complications ensue (e.g., haemorrhage, perforation, obstruction, carcinoma)
• Long-standing ulcerative colitis (because of increased risk of carcinoma)

Definitive Operative Procedure for Ulcerative Colitis:

Total proctocolectomy with permanent ileostomy or ileal-anal pouch anastomosis

Depending on patient circumstance, a variation of this procedure is still used today, with often staged procedures taking place.

Total Proctocolectomy with Ileoanal Pouch Pull-Through:

This is now the operation of choice.

Features:

• Performed with a surgically constructed ileal reservoir, thereby sparing the patient a permanent abdominal ileostomy
• Both J-stapled and W-handsewn pouches can be fashioned, with the lower aspect of the pouch stapled to the upper anal canal
• Generally done by specialist colorectal surgeons

Recent variation:

• Removes the colon and all but 1cm of the rectum
• The remaining rectal stump receives a stapled anastomosis
• Concern: Does not represent a cure because diseased mucosa is left behind, raising the possibility of subsequent development of cancer in the retained rectal stump

Surgical Staging Options:

"One-stage" procedure:

• The advantage of the stapled operation is that very often it can be done without a diverting ileostomy, if the patient is reasonably well
• Commonly used for patients having a planned elective operation

"Two-stage" procedure:

• Patients with toxic megacolon, perforation, or other complications have much higher morbidity and mortality rates, so early surgery may be indicated
• First stage: Total colectomy, end ileostomy and rectal stump/mucous fistula is generally done
• Second stage: The patient returns for the pouch operation in 3-6 months

Key Differences in Surgical Outcomes:

Aspect	Ulcerative Colitis	Crohn's Disease
Surgical outcome	Curative	Useful for complications only
Recurrence after surgery	No	Common