inflammatory bowel disease

Last reviewed 01/2023

Inflammatory bowel disease (IBD) term embraces a group of idiopathic chronic inflammatory intestinal conditions which include two main disease categories with similar, but distinct, pathological conditions:

  • ulcerative colitis
  • Crohn's disease (1)

The pathogenesis of IBD is unknown (1). There are many overlapping clinical, radiological, endoscopic, and histological characteristics, but equally, there are clear differences in the distribution and depth of inflammation within the gastrointestinal tract.

Crohn's disease is a transmural process that may affect any part of the gastrointestinal tract, whereas in uncomplicated ulcerative colitis, inflammation is confined to the colonic mucosa.

In cases of inflammatory bowel disease that are difficult to distinguish, specialised investigations are available. For example, some cases of ulcerative colitis are ANCA-positive and expression of CD44v6 and v3 epitopes in crypt epithelial cells has been noted.

Patients with insufficient findings to determine whether they have Crohn's disease or ulcerative colitis are said to have indeterminate colitis. Around 10% of children with IBD have indeterminate colitis (5).