Gastro - IBD

Question 1

How do ulcerative colitis and Crohn’s disease differ?

Answer 1

Inflammatory bowel disease is a chronic condition that involves inflammation of the gut. It has two main subtypes: ulcerative colitis (UC), which only affects the colon, and Crohn’s disease, which can affect any part of the gut from the mouth to the anus. Both disease processes may be complicated by extraintestinal manifestations.

UC
- Disease confined to the colon
- Inflammation is uniform and diffuse
- Inflammation usually not
transmural (limited to the
mucosa and submucosa)
- Gross rectal bleeding always occurs
- Perianal lesions never occur
- Lead-pipe colon on barium follow-through
- Toxic megacolon, Haemorrhage, Colon cancer

Crohn’s
- Small bowel involved in 80% of cases. Mouth to anus distribution
- Patchy, discrete ulceration: skip lesions
- Transmural, granulomatous inflammation
- Gross rectal bleeding is rare
- Fistula and abscess development is common
- Perianal lesions are significant
- String sign on barium follow-through Cobblestone mucosa
- Fistulae, Abscesses
Strictures, Bowel obstruction

Question 2

What are the extra-intestinal manifestations of ulcerative
colitis?

Answer 2

Eyes
– Episcleritis
– Iritis
– Conjunctivitis

Skin
– Pyoderma gangrenosum
– Erythema nodosum
– Clubbing

Musculoskeletal
– Arthritis
– Sacroileitis
– Ankylosing spondylitis

Hepatobiliary
– Primary sclerosing cholangitis
– Cholangiocarcinoma
– Gallstones

Haematological
– Thromboembolic disease

Other
– Amyloidosis

Question 3

What factors impact on mortality and morbidity in the critically ill patient with IBD?

Answer 3

The following factors may influence the critically ill patient:

1 Disease severity
2 Immunosuppression
3 Nutritional status

Question 4

Discuss the immunosuppressive agents used in the
management of IBD

Answer 4

• Corticosteroids - Prednisolone Prolonged exposure increases infection risk
  and may result in prolonged wound healing,- hyperglycaemia and adrenal insufficiency
• Aminosalicyclates - Mesalazine, Sulphasalazine - Serious idiosyncratic reactions (Stevens-Johnson syndrome, pancreatitis, agranulocytosis or alveolitis) are rare
• Thiopurines - Azathioprine, Mercaptopurine - Thiopurine-associated myelotoxicity, Hepatotoxicity and pancreatitis, Risk of non-melanoma skin cancer
• Anti-metabolite - Methotrexate - Hepatotoxicity, Pneumonitis, Opportunistic infections
• Calcineurin inhibitors - Ciclosporin - Renal impairment, Neurotoxicity
• Anti-TNF therapies - Infliximab, Adalimumab - Increased risk of infections from intracellular pathogens (in particular TB), Opportunistic infections, Infusion reactions

Question 5

Why might patients with IBD require HDU/ICU admission?

Answer 5

The following indications may necessitate admission to critical care:
1 Complications specific to IBD
i Severe exacerbations of disease
ii Perforation
iii Toxic megacolon
iv Acute GI haemorrhage
v Electrolyte imbalance
– Hypokalaemia in particular is very common due to loss of potassium-rich
faecal fluid and steroids
2 Post-operative management of both elective and emergency surgical
procedures
3 Septic complications
4 Thromboembolic complications
5 Other illnesses unrelated to the IBD

Question 6

What are the differential diagnoses of colitis?

Answer 6

Colitis describes inflammation of the colon of any aetiology. Causes include:
1 Ulcerative colitis
2 Crohn’s colitis
3 Diverticular colitis
4 Radiation
5 Ischaemic colitis
6 Infective causes, e.g. E. coli, Shigella, Salmonella, Campylobacter, C. difficile
pseudomembranous colitis
7 Drug induced
8 Typhlitis

Question 7

What is severe colitis and how is it managed?

Answer 7

Severe colitis is characterised by:
1 >6 stools per day plus one of the following signs of systemic toxicity
2 HR >90 bpm
3 Temperature >37.8°C
4 Hb <105 g/l
5 ESR >30 mm/hour
The patient with acute colitis should be managed with an ABCDE approach,
treating abnormalities as they are found. Specific management involves:
1 Initial investigations
i Blood tests (FBC, U&E, LTFs, ESR, CRP)
ii Autoantibodies if diagnostic uncertainty
iii Imaging: abdominal X-ray (AXR) to exclude toxic dilatation, erect CXR if
any suspicion of perforation
iv Stool culture: MC+S; ova, cysts and parasites; C. difficile toxin
2 Ongoing management
i Fluid resuscitation and electrolyte replacement +/– blood as necessary
ii Frequent abdominal examination
iii Stool charts
iv Broad-spectrum antibiotics if sepsis is suspected
v Avoid medications that reduce GI motility such as opiates
3 For severe acute ulcerative colitis also consider:
i High dose IV steroids
ii Pharmacological and mechanical thromboprophylaxis (increased risk of
DVT in this group)
iii Close liaison with surgical team – surgery is usually necessitated if no
improvement/deterioration within 5 days of treatment

Question 8

What is toxic megacolon and how is it managed?

Answer 8

Toxic megacolon is defined as a transverse colon diameter >5.5 cm or caecum diameter >9 cm on plain abdominal radiograph, in a patient with features of
severe colitis and systemic disturbance. It is important to remember signs may be
masked by steroid therapy in ulcerative colitis.
In the absence of other complications, it is reasonable to allow a trial of medical
therapy for 24 hours under the close supervision of the gastroenterologist and
surgical team:
1 Aggressive fluid resuscitation +/– vasopressor support
2 Broad spectrum IV antibiotics
3 Nil-by-mouth with NG tube placement for bowel decompression
Urgent surgery is indicated if:
1 The colonic diameter does not decrease within 24 hours
2 The colonic diameter increases within 24 hours
3 There is a persistent temperature/tachycardia after 24 hours of treatment.