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Key takeaways

Peritonitis is an uncommon condition in cats described as inflammation of the peritoneal cavity (abdominal cavity). Peritonitis may be septic (caused by an infectious agent) or aseptic (sterile).

  • Septic peritonitis is most commonly caused by bacteria, but fungal and parasitic infections occur in rare cases
  • Aseptic peritonitis can occur due to organ rupture, cancer, and feline infectious peritonitis (FIP)
  • Symptoms can vary depending on the root cause but include fever, weakness, pale gums, swelling of the abdomen, vomiting, shock, collapse, and fluid accumulation in the abdomen
  • Diagnostics include imaging, blood work, fluid analysis, and a physical examination
  • Treatment depends on the underlying causes and can include surgery, antibiotics, symptom management, and fluid therapy
  • Prognosis depends on the underlying cause but is typically guarded to poor
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A closer look: Peritonitis in Cats

Peritonitis is a severe and potentially deadly condition in cats which requires emergency veterinary intervention. Peritonitis is uncommon, and typically causes rapid deterioration. The best chance for survival is aggressive medical intervention.

Risk factors

Symptoms vary depending on the underlying cause of the peritonitis. Sepsis may occur, and severe cases may cause rapid death.

Possible causes

Peritonitis is most often caused by a contamination of the abdominal cavity (septic peritonitis).

Possible causes include:

  • Penetrating wound
  • Surgical contamination or opening of surgical wounds
  • Ruptured intestines (typically secondary to a foreign body obstruction)
  • Spread of urinary tract infection
  • Parasitic infection
  • Fungal infection

Main symptoms

In addition, symptoms of dehydration may be present, which include tacky gums, sunken eyes, and delayed skin turgor.

Testing and diagnosis

After a medical history and physical examination a number of tests can be done to determine a diagnosis;

  • Diagnostic imaging
  • Bacterial cultures
  • Blood work
  • Urinalysis
  • Analysis of abdominal fluid

Steps to Recovery

Once peritonitis is confirmed, initial treatment is symptomatic including balancing electrolyte levels, fluid treatments, and pain management. Depending on the cause of the peritonitis, treatments can include;

  • Antibiotics
  • Surgery
  • Symptom management
  • Palliative care

Prognosis is guarded to poor for peritonitis in cats. Depending on the cause, early and aggressive treatment may result in a good prognosis, but these cases typically require extensive medical care and hospitalization.


Prevention steps that can be taken include monitoring changes in overall pet health, close monitoring of pets to avoid trauma/injury, and avoiding ingestion of foreign objects which can cause intestinal ruptures. Staying up to date with vaccines, especially for outdoor cats, reduces the risk of infectious diseases, including FIP.

Is Peritonitis in Cats common?

Peritonitis is uncommon in cats.

Typical Treatment

  • Antibiotics
  • Surgery
  • Symptom management
  • Palliative care


Thomas Wittek - Writing for Merck Veterinary Manual
Maurice E. White - Writing for Cornell University College of Veterinary Medicine
Sandra C. Mitchell - Writing for PetMD

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