- Most intraabdominal infections are “secondary” infections that are polymicrobial and are caused by a defect in the GI tract that must be treated by surgical drainage, resection, and/or repair.
- Primary peritonitis is generally caused by a single organism (Staphylococcus aureus in patients undergoing chronic ambulatory peritoneal dialysis [CAPD] or Escherichia coli in patients with cirrhosis).
- Secondary intraabdominal infections are usually caused by a mixture of bacteria, including enteric Gram-negative bacilli and anaerobes, which enhance the pathogenic potential of the bacteria.
- For peritonitis, early and aggressive IV fluid resuscitation and electrolyte replacement therapy are essential. A common cause of early death is hypovolemic shock caused by inadequate intravascular volume and tissue perfusion.
- Treatment is generally initiated on a “presumptive” or empirical basis and should be based on the likely pathogen(s) and local resistance patterns.
- Antimicrobial regimens for secondary intraabdominal infections should include coverage for enteric Gram-negative bacilli and anaerobes. Antimicrobials that may be used for the treatment of secondary intraabdominal infections depending on severity of illness and microbiology data include (a) third-generation cephalosporin (ceftriaxone or cefuroxime) with metronidazole, (b) ticarcillin–clavulanate or piperacillin–tazobactam, (c) a carbapenem (imipenem, meropenem, doripenem, and ertapenem), and (d) quinolone (levofloxacin or ciprofloxacin) plus metronidazole or moxifloxacin alone.
- Treatment of patients with peritoneal dialysis-associated peritonitis should include an antistaphylococcal antimicrobial such as a first-generation cephalosporin (cefazolin) or vancomycin (intraperitoneal administration is preferred).
- The duration of antimicrobial treatment should be for 4 to 7 days for most secondary intraabdominal infections.
- Patients treated for intraabdominal infections should be assessed for the occurrence of drug-related adverse effects, particularly hypersensitivity reactions (β-lactam antimicrobials), diarrhea (most agents), fungal infections (most agents), and nephrotoxicity (aminoglycosides).
On completion of the chapter, the reader will be able to:
Define and describe the difference between primary, secondary, tertiary, complicated, and uncomplicated intraabdominal infections.
Define the terms abscess and peritonitis.
Describe the typical microbiology of intraabdominal infections.
Describe the typical clinical presentation of peritonitis and intraabdominal abscess.
Describe the appropriate role of culture and susceptibility information for diagnosis and treatment of intraabdominal infections.
Describe the most appropriate drug and nondrug measures to treat intraabdominal infections.
Provide examples of antimicrobial agents that would be appropriate to treat a secondary intraabdominal infection such as an appendiceal abscess.
Describe the appropriate antimicrobial treatment for a primary intraabdominal infection such as peritonitis associated with liver cirrhosis.
Describe the proper duration of treatment of an intraabdominal infection given details of the patient condition and type of infection.
Describe the proper assessment of patients during treatment of intraabdominal infections.
Intraabdominal infections are those contained within the peritoneal cavity or retroperitoneal space. The peritoneal cavity extends from the undersurface of the diaphragm to the floor of the pelvis and contains the stomach, small bowel, large bowel, liver, gallbladder, and spleen. The duodenum, pancreas, kidneys, adrenal glands, great vessels (aorta and vena cava), and most mesenteric vascular structures reside in the retroperitoneum. Intraabdominal infections may be generalized or ...