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Inflammatory Bowel Disease J009

Last amended 
16 November 2020
Current RMA Instruments
Reasonable Hypothesis SOP 90 of 2020
Balance of Probabilities SOP91 of 2020
Changes from previous Instruments

SOP Bulletin 217

ICD Coding
  • ICD-9-CM Codes: 555, 556
  • ICD-10-AM Codes: K50, K51
Brief description

This is a group of autoimmune systemic inflammatory bowel conditions which comprises chiefly Crohn (or Chrohn's) disease and ulcerative colitis.  Additionally, the SOP covers ‘inflammatory bowel disease of unspecified type’. This disease has features of Crohn disease and ulcerative colitis but does not fit neatly into either classical subtype (see further comments below).

Confirming the diagnosis

The diagnosis is confirmed by histopathology of a biopsied section of bowel obtained through gastrointestinal endoscopy.  Radiological imaging may also be undertaken.

The relevant medical specialist is a gastroenterologist or general surgeon.

Additional diagnoses covered by SOP
  • Crohn/Crohn’s disease
  • Ulcerative colitis
  • Regional enteritis
  • Inflammatory bowel disease of unspecified type (this is a specific diagnostic entity)

Note: Extraintestinal manifestations attributable to inflammatory bowel disease (IBS) can be considered to be part of an IBS diagnosis and do not need to be separately diagnosed.  Such manifestations can include peripheral arthritis, axial arthritis (sacroiliitis/spondylitis), eye manifestations (e.g. uveitis) and skin conditions (e.g. erythema nodosum and pyoderma gangrenosum).

Conditions excluded from SOP
  • Bowel inflammation secondary to:
    • food allergy#
    • vascular insufficiency#
    • infection#
    • known toxins#
    • radiation#
  • Diverticular disease*
  • Irritable bowel syndrome*

* another SOP applies

# non-SOP condition

Clinical onset

Inflammatory bowel disease typically manifests with a gradual onset of gastrointestinal symptoms such as diarrhoea, abdominal pain, weight loss and blood in the stools.  There may also be systemic symptoms such as fatigue and extraintestinal manifestations such as arthritis, eye involvement and skin changes.  Symptoms tend to be episodic. Diagnosis may be delayed.  Once the diagnosis is confirmed the clinical onset may be able to be back-dated to the commencement of relevant symptoms.

Clinical worsening

The course of the disease is highly variable.  Commonly there are exacerbations followed by long periods of complete remission, but with an overall deterioration over time with more extensive and severe disease developing.  A recurrence of active disease after a period of remission will not generally represent a worsening beyond the normal course of the disease.


Inflammatory bowel disease is a serious condition which causes significant impairment from the disease itself and from the necessary medications (which may include glucocorticoids) used to treat the disease. The condition can be fatal and is also associated with an increased risk of bowel cancer.

Ulcerative colitis affects the mucosa (lining) of the colon, whereas Crohn disease affects the full thickness of the bowel wall, and can affect any part of the gastrointestinal tract from the mouth to the anus. In the case of ulcerative colitis the affected area will be contiguous, but with Crohn disease, there may be several affected segments of bowel, with disease free bowel inbetween.