Category:Intestine - Inflammatory Pathology

Introduction

Inflammation of the Intestines

• Inflammation involving small or large intestine is known as enteritis.
  • More specific segments may be involved, for example
    • Caecum - typhlitis
    • Colon - colitis
    • Rectum - proctitis
• 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.

Types and Causes of Inflammation

• As with other sections of the alimentary system, there several different types of inflammation that occur in the intestines.
• Even quite mild inflammatory lesions can have quite severe effects, especially if they go on for any length of time.
• The major pathological entities are outlined below.

Inflammation - Contents

Catarrhal Enteritis

• Pathology of Catarrhal Enteritis
• Catarrhal Enteritis Caused by Parasites
• Mixed Viral Enteritis
  • Undifferentiated Neonatal Calf Diarrhoea
  • Winter Dysentery
  • Transmissible Gastro-Enteritis (TGE)
• Bacterial Enteritis
  • Colibacillosis
  • Enterotoxaemia - Pulpy Kidney Disease

Ulcerative Enteritis

• Ulcerative Enteritis
• Swine Fever
• Cyathostomosis

Fibrinous/ Haemorrhagic Enteritis

• Pathology of Fibrinous/ Haemorrhagic Enteritis
• Salmonellosis
• Swine Dysentery
• Parvovirus Enteritis
• Bacterial septicaemia and enteritis
  • Lamb Dysentery
  • Colitis X

Proliferative Enteritis

• Paratuberculosis (Johnes Disease)
• Proliferative Enteritis in Other Species
  • Granulomatous Colitis
  • Porcine Adenomatosis Complex

Granulomatous Enteritis

• Paratuberculosis (Johnes Disease) - see under Proliferative Enteritis
• Feline Infectious Peritonitis

Inflammatory Bowel Disease And Related Conditions

• Lymphocytic - Plasmacytic Enteritis
• Eosinophilic Enteritis
• Idiopathic Eosinophilic Enteritis
• Granulomatous Enteritis
• Idiopathic colitis
• Histiocytic Ulcerative Colitis
• Lymphangiectasia

Villus Atrophy

• Epithelial Renewal
• Villus Atrophy
• Enteritis Particularly Associated with Villus Atrophy
  • Rotavirus
  • Cryptosporidium

Genetic Conditions Causing Enteritis

• Gluten-Sensitive Enteropathy

Protein-Losing Diseases

• Protein-Losing Enteropathy (PLE)