Crohn's disease: management

Crohn's disease: management

Crohn's disease is a form of inflammatory bowel disease. It commonly affects the terminal ileum and colon but may be seen anywhere from the mouth to anus. NICE published guidelines on the management of Crohn's disease in 2012.

General points

• patients should be strongly advised to stop smoking
• some studies suggest an increased risk of relapse secondary to NSAIDs and the combined oral contraceptive pill but the evidence is patchy

Inducing remission

• glucocorticoids (oral, topical or intravenous) are generally used to induce remission
  glucocorticoids (oral, topical or intravenous) are generally used to induce remission
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  . Budesonide is an alternative in a subgroup of patients
• enteral feeding with an elemental diet may be used in addition to or instead of other measures to induce remission, particularly if there is concern regarding the side-effects of steroids (for example in young children)
• 5-ASA drugs (e.g. mesalazine) are used second-line to glucocorticoids but are not as effective
• azathioprine or mercaptopurine* may be used as an add-on medication to induce remission but is not used as monotherapy. Methotrexate is an alternative to azathioprine
• infliximab is useful in refractory disease and fistulating Crohn's. Patients typically continue on azathioprine or methotrexate
• metronidazole is often used for isolated peri-anal disease

Maintaining remission

• as above, stopping smoking is a priority (remember: smoking makes Crohn's worse, but may help ulcerative colitis)
• azathioprine or mercaptopurine
  Azathioprine or mercaptopurine is used first-line to maintain remission in patients with Crohn's
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  Importance: 100
  is used first-line to maintain remission

+TPMT activity

TPMT activity should be assessed before offering azathioprine or mercaptopurine therapy in Crohn's disease

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Importance: 79

should be assessed before starting

• methotrexate is used second-line

Surgery

• around 80% of patients with Crohn's disease will eventually have surgery
• stricturing terminal ileal disease → ileocaecal resection
• segmental small bowel resections
• stricturoplasty
• perianal fistulae
  • an inflammatory tract or connection between the anal canal and the perianal skin
  • MRI
    MRI
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    is the investigation of choice for suspected perianal fistulae - can be used to determine if there (is an abscess and if the fistula is simple (low fistula) or complex (high fistula that passes through or above muscle layers)
  • patients with symptomatic perianal fistulae are usually given oral metronidazole
    metronidazole
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  • anti-TNF agents such as infliximab may also be effective in closing and maintaining closure of perianal fistulas
  • a draining seton
    draining seton
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    is used for complex fistulae
  • a seton is a piece of surgical thread that's left in the fistula for several weeks to keep it open. This is useful because persisting fistula tracks after premature skin closure predispose to abscess formation
• perianal abscess
  • requires incision and drainage
    incision and drainage
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    combined with antibiotic therapy
  • a draining seton may also be placed if a tract is identified

Complications of Crohn's disease

As well as the well-documented complications described above, patients are also at risk of:

• small bowel cancer (standard incidence ratio = 40)
• colorectal cancer (standard incidence ratio = 2, i.e. less than the risk associated with ulcerative colitis)
• osteoporosis

*assess thiopurine methyltransferase (TPMT) activity before offering azathioprine or mercaptopurine

+PassMedicine Notes

Crohn's disease is a form of inflammatory bowel disease. It commonly affects the terminal ileum and colon but may be seen anywhere from the mouth to anus. NICE published guidelines on the management of Crohn's disease in 2012.

General points

• patients should be strongly advised to stop smoking
• some studies suggest an increased risk of relapse secondary to NSAIDs and the combined oral contraceptive pill but the evidence is patchy

Inducing remission

• glucocorticoids (oral, topical or intravenous) are generally used to induce remission. Budesonide is an alternative in a subgroup of patients
• enteral feeding with an elemental diet may be used in addition to or instead of other measures to induce remission, particularly if there is concern regarding the side-effects of steroids (for example in young children)
• 5-ASA drugs (e.g. mesalazine) are used second-line to glucocorticoids but are not as effective
• azathioprine or mercaptopurine* may be used as an add-on medication to induce remission but is not used as monotherapy. Methotrexate is an alternative to azathioprine
• infliximab is useful in refractory disease and fistulating Crohn's. Patients typically continue on azathioprine or methotrexate
• metronidazole is often used for isolated peri-anal disease

Maintaining remission

• as above, stopping smoking is a priority (remember: smoking makes Crohn's worse, but may help ulcerative colitis)
• azathioprine or mercaptopurine is used first-line to maintain remission

+TPMT activity should be assessed before starting

• methotrexate is used second-line

Surgery

• around 80% of patients with Crohn's disease will eventually have surgery
• stricturing terminal ileal disease --> ileocaecal resection
• segmental small bowel resections
• stricturoplasty
• perianal fistulae
• an inflammatory tract or connection between the anal canal and the perianal skin
• MRI is the investigation of choice for suspected perianal fistulae - can be used to determine if there (is an abscess and if the fistula is simple (low fistula) or complex (high fistula that passes through or above muscle layers)
• patients with symptomatic perianal fistulae are usually given oral metronidazole
• anti-TNF agents such as infliximab may also be effective in closing and maintaining closure of perianal fistulas
• a draining seton is used for complex fistulae
• a seton is a piece of surgical thread that's left in the fistula for several weeks to keep it open. This is useful because persisting fistula tracks after premature skin closure predispose to abscess formation
• perianal abscess
• requires incision and drainage combined with antibiotic therapy
• a draining seton may also be placed if a tract is identified

Complications of Crohn's disease

As well as the well-documented complications described above, patients are also at risk of:

• small bowel cancer (standard incidence ratio = 40)
• colorectal cancer (standard incidence ratio = 2, i.e. less than the risk associated with ulcerative colitis)
• osteoporosis

*assess thiopurine methyltransferase (TPMT) activity before offering azathioprine or mercaptopurine