What Is Septic Peritonitis?

The peritoneum is a membrane that lines the abdominal wall and covers the abdominal organs. Septic peritonitis in animals occurs when this membrane becomes inflamed due to the presence of bacteria and biochemical contaminants in the abdominal cavity.

Peritonitis can be localized (limited, low-level contamination) or diffuse (widespread or poorly controlled contamination). It is classified into three types:

• Primary: Spontaneous infection, often originating from the bloodstream, lymphatics, or gastrointestinal tract (more common in cats).
• Secondary: Caused by an intra-abdominal disease such as digestive tract perforation, foreign body, or abdominal surgery.
• Tertiary: Recurrence or persistence of infection after initial treatment.

Symptoms of Septic Peritonitis in Pets

Symptoms vary based on the cause and severity but may include:

• Lethargy, loss of appetite, vomiting, fever
• Abdominal pain and fluid accumulation in the abdomen
• Hypotension, acidosis, electrolyte imbalances
• Cardiovascular and urinary complications in advanced cases
• Multi-organ failure, septic shock, and risk of death

In cats, heart rate may remain low, and abdominal pain may be subtle. Small amounts of abdominal fluid can also be difficult to detect.

Diagnosing Septic Peritonitis in Pets

Diagnosis typically involves:

• Blood and urine tests: Evaluate hydration, internal organ function, and systemic status.
• Abdominal X-rays: Look for fluid accumulation, reduced organ contrast, or free gas.
• Abdominal ultrasound: More sensitive than X-rays in detecting abdominal fluid and masses.
• Abdominocentesis: Collection and microscopic examination of abdominal fluid for white blood cells, organic debris, and bacteria.
• Bacterial culture and biochemical testing: Identify bacteria and suitable antibiotics.
• Diagnostic peritoneal lavage: Used when fluid collection is challenging.

Treatment of Septic Peritonitis in Pets

Treatment focuses on stabilizing the animal, eliminating infection, and preventing complications.

Stabilization:

• IV fluid therapy to address hypotension and improve circulation
• Oxygen therapy if needed
• Medications to stabilize blood pressure and heart rate
• Emergency administration of broad-spectrum antibiotics

Surgical Intervention:

• Exploratory abdominal surgery is often required to:
  • Identify and correct the cause (digestive perforation, organ rupture, foreign body, etc.)
  • Remove debris and toxins via thorough flushing
  • Install abdominal drainage if needed to prevent fluid buildup

Postoperative Care:

• Continuous monitoring in intensive care
• Pain control with analgesics
• Management of clotting disorders with anticoagulants if required
• Prevention of gastrointestinal ulcers
• Early feeding: A feeding tube may be placed during surgery

Abdominal Drainage: Benefits and Risks

Three types of drainage exist:

• Passive: Gravity-based drainage
• Active: Vacuum-assisted drainage using a pump to prevent contamination
• Open: Leaving the abdominal wall open with sterile dressings (requires intensive care)

Risks of drainage:

• Secondary infection
• Drain blockage
• Loss of proteins and electrolytes

The choice of drainage method depends on infection severity, available resources, and the animal’s overall condition.

Prognosis and Monitoring

The prognosis for septic peritonitis depends on:

• The underlying cause
• Speed of diagnosis and treatment
• Response to surgery and antibiotics
• The animal’s overall health

Mortality rates range from 20% to 68%. Rapid, intensive treatment significantly improves survival chances.

If your pet shows signs of septic peritonitis, seek emergency veterinary care immediately.