Key concepts

© Most intra-abdominal infections are "secondary" infections that are caused by a defect in the GI tract that must be treated by surgical drainage, resection, and/or repair.

O1 Primary peritonitis generally is caused by a single organism (Staphylococcus aureus in patients undergoing continuous ambulatory peritoneal dialysis [CAPD] and Escherichia coli in patients with cirrhosis).

Secondary intra-abdominal infections usually are caused by a mixture of enteric gram-negative bacilli and anaerobes. This mix of organisms enhances 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 expansion and tissue perfusion.

Cultures of secondary intra-abdominal infection sites generally are not useful for directing antimicrobial therapy. Treatment generally is initiated on a "presumptive" or empirical basis.

Antimicrobial regimens for secondary intra-abdominal infections should include coverage for enteric gram-negative bacilli and anaerobes. Antimicrobial agents that may be used for treatment of secondary intra-abdominal infections include the following: (a) a ^-lactam-^-lactamase-inhibitor combination, (b) a carbapenem, and (c) a quinolone plus metronidazole or an aminoglycoside plus clindamycin (or metronidazole).

Treatment of primary peritonitis for CAPD patients should include an antista-phylococcal antimicrobial such as a first-generation cephalosporin (cefazolin) or vancomycin, usually given by the intraperitoneal (IP) route.

The duration of antimicrobial treatment should be for a total of 5 to 7 days for most intra-abdominal infections.

Intra-abdominal infections are those contained within the peritoneal cavity or ret-roperitoneal 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. Intra-abdominal infections may be generalized or localized. They may be contained within visceral structures, such as the liver, gallbladder, spleen, pancreas, kidney, or female reproductive organs. Two general types of intra-abdominal infection are discussed throughout this chapter: peritonitis and abscess.

Peritonitis is defined as the acute inflammatory response of the peritoneal lining to microorganisms, chemicals, irradiation, or foreign-body injury. This chapter deals only with peritonitis of infectious origin.

Patient Encounter 1, Part 1

A 67-year-old man presents to the emergency room in acute distress with abdominal pain, nausea, and vomiting. The patient was in a reasonably good state of health until yesterday evening when he had a sudden onset of excruciating abdominal pain. During the night, he had a few episodes of vomiting, and the pain did not diminish. His physical exam is completely normal and no focal neurologic deficits were observed.

The patient is taking glyburide for noninsulin-dependent diabetes mellitus and has been treated in the past for peptic ulcer disease with ranitidine and omeprazole. He has a history of allergy to various types of pollen but reports no allergies to drugs. He reports moderate consumption of alcohol and smoking two packs of cigarettes per day.

What other information would you like to have about this patient before beginning treatment?

What are the goals of treatment?

An abscess is a purulent collection of fluid separated from surrounding tissue by a wall consisting of inflammatory cells and adjacent organs. It usually contains necrotic debris, bacteria, and inflammatory cells. Peritonitis and abscess differ considerably in presentation and approach to treatment.

Lower Your Cholesterol In Just 33 Days

Lower Your Cholesterol In Just 33 Days

Discover secrets, myths, truths, lies and strategies for dealing effectively with cholesterol, now and forever! Uncover techniques, remedies and alternative for lowering your cholesterol quickly and significantly in just ONE MONTH! Find insights into the screenings, meanings and numbers involved in lowering cholesterol and the implications, consideration it has for your lifestyle and future!

Get My Free Ebook

Post a comment