Peritonitis

Key Features

• Most peritonitis is an acute medical emergency

• Primary bacterial peritonitis

  • Accounts for < 2% of childhood peritonitis

  • Most common causative organisms

    • Escherichia coli

    • Other enteric organisms

    • Hemolytic streptococci

    • Pneumococci

  • Occurs in patients with splenectomy, splenic dysfunction, or ascites (nephrotic syndrome, advanced liver disease, kwashiorkor)

  • Can also occur in infants with pyelonephritis or pneumonia

• Secondary peritonitis

  • Much more common

  • Associated with peritoneal dialysis, abdominal trauma, or ruptured viscus

  • Organisms such as Staphylococcus epidermidis and Candida may cause secondary peritonitis in patients receiving peritoneal dialysis

  • Multiple enteric organisms may be isolated after abdominal injury, bowel perforation, or ruptured appendicitis

  • Intra-abdominal abscesses may form in pelvic, subhepatic, or subphrenic areas

• In patients receiving peritoneal dialysis, peritonitis can be a chronic infection causing milder symptoms

Clinical Findings

• Abdominal pain

• Fever

• Nausea, vomiting

• Acidosis

• Shock

• Abdomen is tender, rigid, and distended, with involuntary guarding

• Bowel sounds may be absent

Diagnosis

• Leukocyte count is high initially (> 20,000/μL) with a predominance of immature forms, and later it may fall to neutropenic levels, especially in primary peritonitis

• Abdominal imaging can confirm the presence of ascites

• Bacterial peritonitis should be suspected if paracentesis fluid

  • Contains > 500 leukocytes/μL or > 32 mg/dL of lactate

  • Has a pH < 7.34; or if the pH is over 0.1 pH unit < arterial blood pH

• Diagnosis is made by Gram stain and culture, preferably of 5–10 mL of fluid for optimal yield

• Blood culture is often positive in primary peritonitis

Treatment

• Antibiotic treatment and supportive therapy for dehydration, shock, and acidosis

• Surgical treatment of the underlying cause of secondary peritonitis

• Removal of infected peritoneal dialysis catheters in patients with secondary peritonitis is sometimes necessary and almost always required if Candida infection is present