Peritonitis

Background

Lateral view showing abdominopelvic cavity.

• Inflammation of serosal membrane lining abdominal cavity and intraabdominal organ
• May be infectious (bacterial, viral, fungal) or sterile (mechanical, chemical)
• Etiology
  • Primary: Hematogenous, spontaneous bacterial peritonitis (SBP)
  • Secondary: Perforation or trauma, most common
  • Tertiary: Persistent/recurrent infection, peritoneal dialysis-associated peritonitis

Clinical Features

• Abdominal pain or discomfort
• Abdominal distention, tenderness
• Rebound, guarding, or rigidity on exam
• Anorexia and nausea
• Guarding or rebound
• Sepsis
• Signs of liver failure
• Spontaneous bacterial peritonitis
  • Fever and chills
  • Abdominal pain or discomfort
  • Worsening or unexplained encephalopathy
  • Diarrhea
  • Ascites
  • Worsening or new-onset renal failure
  • Ileus

Differential Diagnosis

Diffuse Abdominal pain

• Abdominal aortic aneurysm
  • Aortocaval fistula
• Acute gastroenteritis
• Aortoenteric fisulta
• Appendicitis (early)
• Bowel obstruction
  • Large bowel obstruction
    • Ogilvie's syndrome
  • Small bowel obstruction
  • Malignant bowel obstruction
• Bowel perforation
• Diabetic ketoacidosis
• Gastroparesis
• Hernia
• Hypercalcemia
• Inflammatory bowel disease
• Mesenteric ischemia
  • Mesenteric vein thrombosis
• Pancreatitis
• Peritonitis
• Sickle cell crisis
• Spontaneous bacterial peritonitis
• Volvulus

Evaluation

Work-up

• Imaging = CT Abd/pelvis (preferred) or 3-view abdomen XR
  • Ultrasound may reveal certain etiologies
• Other work-up based on clinical suspicion, and may include:
  • CBC, metabolic panel, coags, lipase, UA, stool studies
  • Diagnostic paracentesis to evaluate for SBP (PMN ≥ 250 cells/mm³)

Evaluation

• Generally a clinical diagnosis

Management

• Fluid resuscitation
• Surgical consult
• IR consult if requiring abscess drainage

Intra-Abdominal Sepsis/Peritonitis

	Harbor-UCLA	Santa Monica-UCLA	Other
Primary	Metronidazole 500mg IV q8hrs Plus one of the following: Ceftriaxone 1g IV once daily Ciprofloxacin 400mg IV q12hrs Cefazolin 1g (30mg/kg) IV q8hrs Levofloxacin 750mg IV once daily	Metronidazole 500mg IV q8h + Vancomycin 15mg/kg/dose IV q12h (Max dose = 1500mg) Plus one of the following: Piperacillin/tazobactam 4.5g IV q6h Ertapenem 1g IV q24h Ceftriaxone 1g IV q24h	One of the following: Piperacillin-tazobactam Ticarcillin-clavulanate 3.1 g IV every 6 hours Ertapenem 1 g every 24 hours Moxifloxacin 400 mg IV every 24 hours
Allergy or prior exposure	Piperacillin/Tazobactam 4.5g (80mg/kg) IV q8hrs OR Metronidazole 500mg IV q8hrs PLUS Cefepime 2g IV once daily OR Ciprofloxacin 400mg IV q12hrs OR Levofloxacin 750mg IV once daily Meropenem 1g (20mg/kg) IV q8hrs OR Doripenem 500mg IV q8hrs OR Aztreonam 2g (30mg/kg) IV q8hrs + Metronidazole 500mg IV q8hrs	aztreonam 2g IV q8h + metronidazole 500mg IV q8h +/- vancomycin 15mg/kg/dose IV q12h (Max dose = 1500mg)

Pediatric

• Metronidazole 7.5mg/kg IV q8hrs (max 500mg) + one of:
  • Ceftriaxone 50-75mg/kg IV daily (max 2g) OR
  • Cefotaxime 50mg/kg IV q8hrs (max 2g/dose)
• Piperacillin/Tazobactam 80-100mg/kg IV q6-8hrs (max 4.5g) OR
• Meropenem 20mg/kg IV q8hrs (max 1g)

Disposition

• Admit

See Also

• Abdominal pain