Peritonitis

Classification

Image of acute fibrinous peritonitis from Cornell Veterinary Medicine

• Usually secondary to other abdominal pathology but may be primary
• Localised or diffuse
• Acute (increased fluid in abdominal cavity and roughening of serosal surface of abdominal organs and parietal peritoneum) or chronic (fibrous adhesions involving any of abdominal organs and omentum/mesentery/peritoneum)
• Septic or non-septic
• Types of exudate
  • Sero-fibrinous e.g. Glasser’s disease (Haemophilus parasuis) in pigs
  • Fibrinopurulent e.g. after gut rupture, systemic infection (pasteurellosis in sheep)
  • Purulent e.g. Rhodococcus equi in foals
  • Haemorrhagic e.g. splenic rupture
  • Granulomatous e.g. Nocardia in dogs

Causes of peritonitis

Chemical

Image of bile stained peritonitis in a cat from Cornell Veterinary Medicine

e.g.:

• Bile
• Urine
• Pancreatic enzymes (acute pancreatic necrosis)
• Barium if allowed to leak into peritoneal cavity (causes potentially fatal haemorrhagic peritonitis)
• Surgical glove powder (granulomatous peritonitis)
• Chyle (mild granulomatous serositis)

Bacterial

Tuberculous peritonitis with phagocytosis of lymphocytes (Sourced from Bristol Biomed with permission)

e.g.:

• Penetrating wound
• Gut rupture
• Surgery
• Inflammatory focus e.g. abscess, bacteraemia
• Umbilicus
• Gangrenous intestine or uterus prior to rupture

Viral

Image of FIP by Cornell Veterinary Medicine

e.g.

• Feline infectious peritonitis - in “wet” (effusive) form, sero-fibrinous fluid with high protein (Ig content), tags of fibrin attach to peritoneum and organs

Parasites

e.g.

• Strongyle migration in horses
• Fasciola hepatica - lesions around liver
• See Peritoneal Cavity Parasitic

Sequelae to peritonitis

• Hypermotility initially → hypomotility
  • Ileus - reduces distribution of exudates by intestinal motility
  • Fibrinous adhesions may develop
• Impaired CV function and acid-base imbalance
  • Due to sequestration of fluid and protein in exudate, hypomotile gut, bacterial exo/endotoxins absorbed directly from peritoneal cavity and causing vascular permeability, loss of intestinal absorption
• May resolve, become chronic-active or lead to adhesions.

In dogs

• Fibrinohaemorrhagic peritonitis in infectious canine hepatitis
• Septic peritonitis caused by various agents, often Escherichia coli and anaerobic bacteria through perforation of the gut, rupture of urinary bladder or an abscess
• Putrid peritonitis in uterine rupture with pyometra or septic metritis
• Nocardia infection reults in profuse pink/red fluid due to blood and chronic inflammatory cells
• Granulomatous peritonitis caused by fungi, Nocardia and Actinomyces

In cats

• Putrid peritonitis in uterine rupture due to pyometra or fetal putrefaction
• Peritonitis due to penetrating wounds
• Septic peritonitis due to anaerobes in cat bite abscesses
• Serous peritonitis in cats with feline infectious peritonitis especially in the wet form but exudate occurs also in the dry form
  • Viscous, clear, pale to deep yellow fluid, may contain strands of fibrin

In horses

Image of acute fibrinous peritonitis in a horse from Cornell Veterinary Medicine

• Diffuse acute peritonitis often fatal
• Mostly caused by rupture of stomach or intestine
• In foals purulent peritonitis may be caused by Rhodococcus equi or fibrinous peritonitis by Actinobacillus equuli
• Haemorrhage as a consequence of castration may result in acute non-septic
• Secondary to verminous lesions

In cattle

• Perforation of an abdominal organ, usually reticulum or [[uterus, results in acute diffuse fibrinopurulent peritonitis or local acute and chronic, with adhesions
• Traumatic reticuloperitonitis (hardware disease) may evolve into reticulopericarditis
• Local chronic peritonitis, abscesses containing usually Actinomyces pyogenes
• Fibrinopurulent peritonitis through umbilical infection in calves
• Fibrinous peritonitis in calves with septicaemic colibacillosis
• Serofibrinous peritonitis in sporadic bovine encephalomyelitis
• Diffuse fibrinohaemorrhagic peritonitis in clostridial haemoglobinuria
• Localised peritonitis in clostridial enterotoxaemia (Clostridium perfringens types B and C and braxy)

In sheep

• Fibrinopurulent peritonitis in postpartum septic metritis
• Serofibrinous peritonitis in diseases caused by Mycoplasma
• In penetration of intestines by larvae of Oesophagostomum columbianum

In goats

• Acute fibrinous peritonintis caused by Mycoplasma mycoides

In pigs

• Diffuse fibrinopurulent peritonitis in infections by Actinomyces pyogenes, Escherichia coli or other organisms
• Serofibrinous peritonitis in Glasser’s disease Haemophilus parasuis or Mycoplasma or septicaemias caused by Streptococcus suis type 2
• Acute gelatinous haemorrhagic peritonitis in Anthrax