Intra-Abdominal Infections

3. Intra-Abdominal Infections M_MAHMOUDIEH General Surgeon Department of Surgery

4. Intra-Abdominal Infections • peritonitis or intra-abdominal infection ;Microbial contamination of the peritoneal cavity is termed, and is classified according to etiology. • Primary microbial peritonitis occurs when microbes invade the normally sterile confines of the peritoneal cavity via hematogenousdissemination from a distant source of infection or direct inoculation. This process is more common ;ascites, and renal failure via peritoneal dialysis. These infections invariably are monomicrobial and rarely require surgical intervention. Diagnosisis established based on a patient who has ascites for medical reasons, physical examination that reveals diffuse tenderness , guarding without localized findings, absence of pneumoperitoneumon abdominal flat plate and upright roentgenograms, presence of more than 100 WBCs/mL, and microbes with a single morphology on Gram's stain cultures will typically demonstrate the presence of gram-positive organisms in patients receiving peritoneal dialysis. In patients without this risk factor organisms can include E. coli, K. pneumoniae, pneumococci, and others, although many different pathogens can be causative. • .

5. Primary microbial peritonitis • Treatment Administration of an antibiotic to which the organism is sensitive; Often 14 to 21 days of therapy are required. Removal of indwelling devices (e.g.,peritoneal dialysis catheter or peritoneovenous shunt) may be required for effective therapy of recurrent infections

6. Secondary microbial peritonitis • occurs subsequent to contamination of the peritoneal cavity due to perforation or severe inflammation and infection of an intra-abdominal organ. • Examples include appendicitis, perforation of any portion of the GI tract, or diverticulitis. As noted previously in Source Control,

7. Secondary microbial peritonitis • Therapy • source control to resect or repair the diseased organ; • Débridementof necrotic, infected tissue and debris; • administration of antimicrobial agents directed against aerobes and anaerobes. • This type of antibiotic regimen should be chosen because in most patients the precise diagnosis cannot be established until exploratory laparotomy is performed, and the most morbid form of this disease process is colonic perforation, due to the large number of microbes present. • conversion of a parenteral to an oral regimen when the patient's ileus resolves will provide results similar to those achieved with IV antibiotics. Effective source control and antibiotic therapy is associated with low failure rates and a mortality rate of approximately 5 to 6%; inability to control the source of infection leads to mortality greater than 40%

8. Secondary microbial peritonitis • Patients in whom standard therapy fails • develop an tintra-abdominal abscess, • leakage from a GI anastomosis leading to postoperative peritonitis, or tertiary (persistent) peritonitis. The latter is a poorly understood entity that is more common in immunosuppressed patients in whom peritoneal host defenses do not effectively clear or sequester the initial secondary microbial peritoneal infection. Microbes such as E. faecalis and faecium, S. epidermidis, C. albicans, and P. aeruginosa can be identified, typically in combination, and may be selected based on their lack of responsiveness to the initial antibiotic regimen, coupled with diminished activity of host defenses. • Unfortunately, even with effective antimicrobial agent therapy, this disease process is associated with mortality rates in excess of 50%

9. the presence of an intra-abdominal abscess ; mandated surgical re-exploration and drainage. • diagnosed via abdominal computed tomographic (CT) imaging techniques • drained percutaneously. • Surgical intervention is reserved for those individuals who multiple abscesses, abscesses in proximity to vital structures such that percutaneous drainage would be hazardous, in whom an ongoing source of contamination (e.g., enteric leak) is identified. • The necessity of antimicrobial agent therapy and precise guidelines that dictate duration of catheter drainage have not been established. • A short course (3 to 7 days) of antibiotics that possess aerobic and anaerobic activity seems reasonable, and • most practitioners leave the drainage catheter in situ until it is clear that cavity collapse has occurred, output is less than 10 to 20 mL/d, no evidence of an ongoing source of contamination is present, and the patient's clinical condition has improved.