Abscess, intraabdominal

The causes of intraabdominal abscess overlap those of peritonitis and, in fact, may occur sequentially or simultaneously. Appendicitis is the most frequent cause of abscess. 

Intraabdominal infections have a wide spectrum of clinical features. Peritonitis usually is easily recognized, but intraabdominal abscess often may continue for long periods of time. Patients with primary and secondary peritonitis present quite differently. 

Acute intraabdominal contamination, such as after a traumatic injury, may be treated with a very short course (24 hours) of antimicrobials.25 For established infections (i.e., peritonitis or intraabdominal abscess), an antimicrobial course limited to 5 to 7 days is justified. Under certain conditions, therapy for longer than 7 days would be justified, e.g., if the patient remains febrile or is in poor general condition, when relatively resistant bacteria are isolated, or when a focus of infection in the abdomen still may be present. For some abscesses, such as pyogenic liver abscess, antimicrobials may be required for a month or longer. 

Treatment regimens for intraabdominal infection can be judged as successful if the patient recovers from the infection without recurrent peritonitis or intraabdominal abscess and without the need for additional antimicrobials. A regimen can be considered unsuccessful if a significant adverse drug reaction occurs, reoperation or percutaneous drainage is necessary, or patient improvement is delayed beyond 1 or 2 weeks. 

Parenteral nutrition can be a lifesaving therapy in patients with intestinal failure, but the oral or enteral route is preferred when providing nutrition support ( when the gut works, use it ). Compared with PN, enteral nutrition generally is associated with fewer infectious complications (e.g., pneumonia, intraabdominal abscess, and catheter-related infections) and potentially improved outcomes.1-3 However, if used in appropriate patients (i.e., patients with questionable intestinal function or when the intestine cannot be used), PN can be used safely and effectively and may improve nutrient delivery.4 Indications for PN are listed in Table 97-1.1... 

Table 42-1 summarizes many of the potential causes of bacterial peritonitis. The causes of intraabdominal abscess somewhat overlap those of peritonitis and, in fact, both may occur sequentially or simultaneously. Appendicitis is the most frequent cause of abscess. Intraabdominal infection results from entry of bacteria into the peritoneal or retroperitoneal spaces or from bacterial collections within intraabdominal organs. When peritonitis results from peritoneal dialysis, skin surface flora are introduced via the peritoneal catheter. 

If peritonitis continues untreated, the patient may experience hypovolemic shock from fluid loss into the peritoneum, bowel wall, and lumen. This may be accompanied by generalized sepsis. Intraabdominal abscess may pose a diagnostic challenge as the symptoms are neither specific nor dramatic. 

Acute intraabdominal contamination, such as after a traumatic injury, may be treated with a short course (24 hours). For established infections (peritonitis or intraabdominal abscess), an antimicrobial course of at least 7 days is justified. 

Intraabdominal infections have a wide spectrum of clinical features often depending on the specific disease process, the location and the magnitude of bacterial contamination, and concurrent host factors. Patients with primary and secondary peritonitis present quite differently (Table 42-3). If peritonitis continues untreated, the patient may experience hypovolemic shock from fluid loss into the peritoneum, bowel wall, and lumen. This may be accompanied by generalized sepsis. Intraabdominal abscess may pose a diagnostic challenge as the symptoms are neither specific nor dramatic. 

Intraabdominal abscess may pose a difficult diagnostic challenge because the symptoms are neither specific nor dramatic. The patient may complain of abdominal pain or discomfort, but these symptoms are not reliable. Fever usually is present often it is low grade, but it may be high, with a spiking pattern. The patient may have a paralytic ileus and abdominal distension. The abdominal examination is unreliable tenderness and pain may be present, and a mass may be palpated. 

Laboratory studies generally are not helpful in the diagnosis of intraabdominal abscess, although most patients will have leukocytosis. Some patients may have positive blood cultures, whereas others, particularly diabetics, may have hyperglycemia. The finding of Bacteroides or any two enteric bacteria in the bloodstream is often indicative of an intraabdominal infectious process. 

Radiographic methods are used to make the diagnosis of an intraabdominal abscess. Plain radiographs may show air-fluid levels or a shift of normal intraabdominal contents by the abscess mass. G1 contrast smdies also may demonstrate this displacement of abdominal structures. Both these modahties provide indirect evidence of abscess presence but are not generally helpful in precisely locating the abscess. 

Ultrasound is a frequent first diagnostic method used when an intraabdominal abscess is suspected. The procedure may be done at the bedside, which is particularly helpful in the patient in the intensive care unit. In some patients, particularly the obese, it is technically difficult to perform and interpret the examination. ... 

Magnetic resonance imaging (MRl) is used infrequently to locate an intraabdominal abscess, particularly in the retroperitoneum, but this modality offers no significant advantage when compared with CT scan. 

Primary peritonitis is treated with antimicrobials and rarely requires drainage. Secondary peritonitis requires surgical correction of the underlying pathology. The drainage of the purulent material is the critical component of management of an intraabdominal abscess. Without adequate drainage of the abscess, antimicrobial therapy and fluid resuscitation can be expected to fail. 

Onderdonk AB, Bartlett JG, Louie T, et al. Microbial synergy in experimental intraabdominal abscess. Infect Immun 1997 13 22-26. 

Montgomery RS, Wilson SE. Intraabdominal abscesses Image-guided diagnosis and therapy. Clin Infect Dis 1996 23 28-36. 

Shuler FW, Newman CN, Angood PB, et al. Nonoperative management for intraabdominal abscesses. Am Surg 1996 62 218-222. 

Kim HB, Gregor MB, Boley SJ, Kleinhaus S. Digitally assisted laparoscopic drainage of multiple intraabdominal abscesses. J Laparoendosc Surg 1993 3 477 79. 

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