Canis ISSN: 2398-2942


Contributor(s): Kyle Braund, James Simpson, Zoe Halfacree


  • Peritonitis may be diffuse (when the whole of the peritoneal cavity is involved) or localized (where the process becomes walled-off, generally by the omentum).
  • Cause: usually the result of bacterial peritoneal contamination.
  • Signs: acute diffuse bacterial peritonitis may cause pyrexia, depression, pain, sometimes vomiting and will progress to septic shock with tachycardia and hypovolemia.
  • Diagnosis: palpation, radiography, ultrasonography and abdominocentesis.
  • Treatment: manage hypovolemia and endotoxic shock, then surgical exploration to address underlying cause.
  • Prognosis: guarded.
Print off the owner factsheet on Peritonitis Peritonitis to give to your client.




  • Very rarely hematogenous in the dog.


  • Gastrointestinal tract leakage secondary to:
    • Gastrointestinal tract wound dehiscence following surgery (most common cause) .
    • Foreign bodies that damage and devitalize intestinal tissue, especially linear FBs Intestine: linear foreign bodies .
    • Non-steroidal anti-inflammatory drugs and/or corticosteroids that ulcerate gastric and small intestinal mucosa.
    • Infiltrative and erosive neoplasms.
    • Intussception Intussusception.
    • Intestinal/mesenteric volvulus.
    • Penetrating abdominal wounds.
    • Ischemic intestinal disease .
The risk of septic peritonitis following gastrointestinal surgery is greatest at 3-5 days post-operatively and careful monitoring is imperative during this time. Any signs of deterioration should be followed with thorough patient assessment to rule out septic peritonitis.
  • Bacterial contamination from ruptured urogenital tract (pyometra Pyometra, prostatic abscess ).
  • Migrating foreign bodies, eg ruptured sublumbar abscess.
  • Post-surgical infection following any abdominal surgery.
  • Bile from extra-hepatic biliary trauma or gall bladder necrosis.
  • Urine from urinary tract trauma Bladder: trauma rupture.
  • Pancreatic enzymes released in pancreatitis Pancreatitis: acute.
  • Particulate matter, eg talc or gauze fibers following surgical intervention , barium leakage from perforated bowel following a radiological study.
  • Migrating parasitic larvae.


  • Leakage of intestinal bacteria into the peritoneal cavity induces inflammation of the mesothelial cells lining the peritoneal cavity resulting in activation of pro-inflammatory mediators.
  • Consequent increased microvascular permeability to causes transudation of plasma protein, electrolytes and phagocytic cells. Excessive nitrous oxide release results in arteriovenous dilation and decreased systemic vascular resistance, systemic hypotension and compensatory tachycardia. 
  • Bacteria or bacterial components, such as gram-negative lipopolysaccharide, may be absorbed resulting in bacteremia and potentially septic shock Shock: septic.
  •  A systemic response due to inflammatory mediator release will then result in the release of catcholamines and adrenocortical hormones.
  • Exudation of fluid into the peritoneal cavity (third spacing) results in profound electrolyte derangements, hypovolemia and hypoalbuminemia.
  • Systemic inflammtory response syndrome Systemic inflammatory response syndrome (SIRS) , multiple organ dysfunction Multiple organ dysfunction syndrome, disseminated intravascular coagulation Disseminated intravascular coagulation → death.


  • Peracute with intestinal rupture, septic bile peritonitis, septic uroperitoneum.


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Further Reading


Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Dayer T, Howard J, Spreeng D (2013) Septic peritonitis from pyloric and non-pyloric gastrointestinal perforation: prognostic factors in 44 dogs and 11 cats. JSAP 54 (12), 625-629 PubMed.
  • Cioffi K M, Schmiedt C W, Cornell K K, Radlinsky M G (2012) Retrospective evaluation of vacuum-assisted peritoneal drainage for the treatment of septic peritonitis in dogs and cats: 8 cases (2003-2010). J Vet Emerg Crit Care (San Antonio) 22 (5), 601-609 PubMed.
  • Ragetly G R, Bennett R A, Ragetly C A (2011) Septic peritonitis: treatment and prognosis. Compend Contin Educ Vet 33 (10), E1-5, quiz E6 PubMed.
  • Bonczynski J J, Ludwig L L, Batron L J, Loar A, Peterson M E (2003) Comparison of peritoneal fluid and peripheral blood pH, bicarbonate, glucose, and lactate concentration as a diagnostic tool for septic peritonitis in dogs and cats. Vet Surg 32 (2), 161-166 PubMed.
  • Staatz A J, Monnet E, Heim H B 3rd (2002) Open peritoneal drainage versus primary closure for the treatment of septic peritonitis in dogs and cats: 42 cases (1993-1999). Vet Surg 31 (2), 174-180 PubMed.