Peritonitis in Cats: A Vet’s 2025 Guide to Diagnosis, Causes & Life-Saving Care 🐾

Hello! I’m Dr. Duncan Houston BVSc, founder of Ask A Vet. Peritonitis is inflammation of the abdominal lining—a surgical emergency in cats. In this comprehensive 2025 guide, we'll explore causes (septic vs aseptic), essential diagnostics, surgical and medical protocols, and compassionate home-care strategies designed to achieve the best outcomes.

📘 1. What Is Peritonitis?

Peritonitis refers to inflammation of the peritoneum—the membrane that lines the abdominal cavity—which may be septic (infection) or aseptic (sterile inflammation) :contentReference[oaicite:3]{index=3}. Regardless of cause, it can quickly become life-threatening.

⚠️ 2. Common Causes & Risk Factors

Peritonitis in cats can arise from:

• Septic: bacterial contamination due to intestinal perforation (foreign bodies, ulcers), ruptured bladder or uterus, abdominal wounds, abscesses :contentReference[oaicite:4]{index=4}.
• Aseptic: Feline Infectious Peritonitis (FIP) caused by mutated coronavirus, or leakage of pancreatic enzymes :contentReference[oaicite:5]{index=5}.

👀 3. Signs to Watch For

• Sudden abdominal swelling (ascites)
• Fever, lethargy, anorexia, vomiting, diarrhea
• Pain on abdominal palpation, often “prayer position” leaning forward :contentReference[oaicite:6]{index=6}
• Rapid breathing or shock (pale gums, tachycardia)

🔍 4. Diagnostic Approach

1. Physical exam & history: fever, pain, distended abdomen.
2. Bloodwork: CBC, chemistry, assess organ function & dehydration.
3. Abdominal ultrasound: detect free fluid—often echogenic if septic :contentReference[oaicite:7]{index=7}.
4. Abdominocentesis & fluid analysis: check for WBCs, bacteria—septic fluid often contains neutrophils and rods :contentReference[oaicite:8]{index=8}.
5. Imaging or biopsy for FIP: Rivalta testing, coronavirus PCR, and clinical pathology—FIP diagnosis is complex :contentReference[oaicite:9]{index=9}.
6. Advanced imaging: CT or ultrasound to locate perforation or tumor.

🛠️ 5. Emergency Treatment Strategies

a) Septic Peritonitis

• Surgical exploration: close perforation, lavage cavity, place drains as needed :contentReference[oaicite:10]{index=10}.
• Antibiotics: broad-spectrum IV tailored to culture results.
• Fluid resuscitation: IV fluids to correct shock and dehydration.
• Pain relief: opioids or NSAIDs once stable.
• Post-op monitoring: watch for infection, leakage, or organ dysfunction.

b) Aseptic / FIP-related

• Medical management: immunomodulators, anti‑inflammatories (e.g., low‑dose steroids).
• Antivirals like GS‑441524/remdesivir: promising treatment for certain FIP forms :contentReference[oaicite:11]{index=11}.
• Supportive care: fluids, appetite support, warmth, symptomatic therapy.
• Drainage: temporary relief of discomfort and respiratory compromise.

📈 6. Prognosis & Outcomes

• Septic cases: Greatly improved prognosis with timely surgery + antibiotics—early intervention is key.
• Non-septic/FIP cases: Prognosis varies—classic FIP was fatal, but antivirals now yield >80% recovery in some studies :contentReference[oaicite:12]{index=12}.
• Long-term care: monitor for recurrence, organ function, and overall growth in kittens.

🏡 7. Home Care & Recovery

• Maintain hydration, provide palatable food like warmed wet diets.
• Schedule appointments for drain removal, culture follow-up, and imaging.
• Monitor for fever, appetite, energy, and surgical site health.
• Log body weight, temperature, and medication reminders in Ask A Vet.
• Adjust environment—quiet, cozy spaces to reduce stress during recovery.

📚 8. Case Studies

“Luna,” a 4-year-old female, presented with sudden belly swelling and fever. Ultrasound showed echogenic abdominal fluid; cytology confirmed septic peritonitis. Emergency surgery repaired a ruptured intestine. After two weeks of hospitalization with fluids, antibiotics, and pain control, she returned home. One month later, Luna is thriving and shows no recurrence.

“Milo,” a 9-month-old kitten with vague symptoms, effusion, and high protein Rivalta-positive fluid. PCR confirmed wet FIP. Treated with GS‑441524 plus supportive care; ascites resolved and energy returned in weeks.

🚨 9. When to Seek Used Veterinary Help

• Swollen abdomen, signs of pain, shock
• Persistent vomiting or lethargy
• Failure to respond to initial treatment or worsening signs
• Kittens, immunocompromised, or multihousehold risk

✨ 10. Final Thoughts

Peritonitis in cats is a medical emergency, but modern diagnostic tools, surgical care, and antivirals offer hope. With Ask A Vet’s tele-triage, medication and recheck reminders, and supportive care guides, you’ll be empowered throughout your cat’s journey—toward recovery and long-term health 🐾.

For tailored aftercare plans, symptom tracking, and 24/7 access to veterinary support, visit AskAVet.com or download the Ask A Vet app. We’re here for you both through crisis and recovery. 🐱❤️