Category:Intestine - Inflammatory Pathology

Inflammation of the Intestines

• Enteritis is extremely common, and is usually associated with diarrhoea.
  • Diarrhoea is the passage of faeces with increased bulk and/or fluid content.
  • However, remember that enteritis may occur without diarrhoea, and diarrhoea can occur without enteritis!

• There are very many causes of enteritis - some are outlined in this section.
  • Laboratory support is usually required for a comprehensive diagnosis, but we must try to narrow the diagnostic options.
  • Diagnosis is aided by noting:
    • Species
    • Age
    • Gross distribution of lesions- i.e. upper or lower small intestine.
    • The effects on the large intestine.
    • The type of mucosal pathology- both grossly and histologically.

Normal Intestinal Structure

• The normal intestinal structure consists of:
  • The mucosa
    • In the small intestine, the epithelium forms villi and crypts.
      • Epithelium is continuously renewed.
    • Also has associated glands.
  • The lamina propria
    • Supportive tissue
  • The muscularis mucosae
  • The submucosa
  • Radial, and then longitudinal, muscle.
  • The serosa.

• Damage due to enteritis results in morphological changes to the normal structure, e.g.
  • Villus atrophy.
  • Apparent elongation of the crypts.
  • Various types of inflammatory cell infiltration.
• However, the bowel may remain morphologically normal in some diarrhoeaic conditions.
  • For example, in hypersecretory diarrhoea due to some bacterial toxins.