Peritonitis and Abdominal Sepsis Treatment & Management

The management approach to peritonitis and peritoneal abscesses targets correction of the underlying process, administration of systemic antibiotics, and supportive therapy to prevent or limit secondary complications due to organ system failure. Treatment success is defined as adequate source control with resolution of sepsis and clearance of all residual intra-abdominal infection.

Early control of the septic source is mandatory and can be achieved by operative and nonoperative means.

Surgical interventions

Operative management addresses the need to control the infectious source and to purge bacteria and toxins. The type and extent of surgery depends on the underlying disease process and the severity of intra-abdominal infection. Definitive interventions to restore functional anatomy involve removing the source of the antimicrobial contamination and repairing the anatomic or functional disorder causing the infection. This is accomplished by surgical intervention. Occasionally, this can be achieved during a single operation; however, in certain situations, a second or a third procedure may be required. In some patients, definitive intervention is delayed until the condition of the patient improves and tissue healing is adequate to allow for a (sometimes) lengthy procedure.

Damage control surgery

Alternatively, over the past decade, in the setting of extensive abdominal inflammatory disease and septic shock, surgeons have used damage control operations (DCS) to temporarily drain the infection, quickly control the visceral leak, and defer any definitive repair until the patient has stabilized. DCS appears to be feasible for perforated diverticulitis and peritonitis or septic shock, whether or not patients are hemodynamically stable. ^{[22, 23, 24]}

See Surgical Approach to Peritonitis and Abdominal Sepsis for more information.

Nonsurgical interventions

Nonoperative interventions include percutaneous abscess drainage, as well as percutaneous and endoscopic stent placements. If an abscess is accessible for percutaneous drainage and if the underlying visceral organ pathology does not clearly require operative intervention, percutaneous drainage is a safe and effective initial treatment approach. With percutaneous treatment, the definition of success includes the avoidance of further operative intervention and, in some cases, the delay of surgery until after resolution of the initial sepsis.

The general principles guiding the treatment of infections are four-fold, as follows ^{[1, 16]} :

1. Control the infectious source

2. Eliminate bacteria and toxins

3. Maintain organ system function

4. Control the inflammatory process

The treatment of peritonitis is multidisciplinary, with complementary application of medical, operative, and nonoperative interventions. Medical support includes the following:

• Systemic antibiotic therapy

• Intensive care with hemodynamic, pulmonary, and renal support

• Nutrition and metabolic support

• Inflammatory response modulation therapy

Early control of the septic source is mandatory and can be achieved by operative and nonoperative means. Nonoperative interventional therapies include percutaneous drainage of abscesses and percutaneous and endoscopic stent placements.

Treatment of peritonitis and intra-abdominal sepsis always begins with volume resuscitation, correction of potential electrolyte and coagulation abnormalities, and empiric broad-spectrum parenteral antibiotic coverage.

Aggressive fluid resuscitation to treat intravascular fluid depletion should be instituted. Pressor agents are avoided if possible. Fluid administration requires frequent monitoring of blood pressure, pulse, urine output, blood gases, hemoglobin and hematocrit, electrolytes, and renal function.

Whenever cultures have been obtained, antibiotic therapy should be appropriately focused on the organisms present. The foundations underlying appropriate antimicrobial therapy comprise timing, spectrum, and dosing. ^[1]  Appropriate resuscitation following known guidelines for sepsis should be instituted as soon as the diagnosis of sepsis is considered.

Antibiotic therapy is used to prevent local and hematogenous spread of infection and to reduce late complications. ^[25] Several different antibiotic regimens are available for the treatment of intra-abdominal infections. ^[25] Both single-agent broad-spectrum therapy and combination therapies have been used. However, no specific therapy has been found to be superior to another therapy. Infection of the abdominal cavity requires coverage for gram-positive and gram-negative bacteria, as well as for anaerobes. Antipseudomonal coverage is recommended in patients who have had previous treatment with antibiotics or who have had a prolonged hospitalization.

The optimal duration of antibiotic therapy must be individualized and depends on the underlying pathology, severity of infection, speed and effectiveness of source control, and patient response to therapy. Antibiotics can be discontinued once clinical signs of infection have resolved. Recurrence is a concern with certain infections, such as those from Candida and Staphylococcus aureus, and treatment should be continued for 2-3 weeks.

Drainage refers to evacuation of an abscess. This can be performed operatively or percutaneously under ultrasound or CT guidance. If the abscess is localized at the level of the skin and underlying superficial tissues, simple removal of sutures or opening of the wound may be sufficient. Percutaneous techniques are preferred when an abscess can be completely drained, and debridement and repair of the anatomic structures are not needed. Factors that may prevent successful source control with percutaneous drainage include diffuse peritonitis, lack of localization of the infectious process, multiple abscesses, anatomic inaccessibility, or the need for surgical debridement. ^[5]

In some instances, success of nonoperative drainage also includes the ability to delay surgery until the acute process and sepsis are resolved and a definitive procedure can be performed under elective circumstances.

Most patients with tertiary peritonitis develop complex abscesses or poorly localized peritoneal infections that are not amenable to percutaneous drainage. Up to 90% of patients will require reoperation for additional source control.

For primary percutaneous management of intra-abdominal abscesses, the etiology, location, and morphology of the abscess must be defined; evaluate for the presence of an ongoing enteric leak or fistula formation. With proper indications, most studies have reported success rates of greater than 80% (range 33-100%) for drainage of localized nonloculated abscesses; however, the success rates depend to some degree on the underlying pathology. In these studies, no significant differences were found between operative and primary nonoperative management with regard to the overall morbidity or length of hospital stay (mean duration of drainage 8.5 d).

In the treatment of diverticular disease, the use of laparoscopic drainage and drain placement and/or resection with or without anastomosis continues to be evaluated. ^[26]

In preliminary results from the Swedish DILALA (DIverticulitis LAparoscopic LAvage) trial, Angenete et al reported that in the short term, laparoscopic lavage may be safe and effective in treating perforated diverticulitis with purulent peritonitis (Hinchey III classification). ^[27] The investigators found no differences in 12-week morbidity and mortality between 39 patients who underwent laparoscopic lavage and 39 patients who underwent a Hartmann procedure (colon resection and stoma). However, the laparoscopic lavage procedure resulted in decreased operative times and reduced recovery time and hospital stays. ^[27]

Common reasons for failure of primary nonoperative management include enteric fistula (eg, anastomotic dehiscence), pancreatic involvement, infected clot, and multiple or multiloculated abscesses. Procedure-related significant complications are reported to occur in less than 10% of cases (range 5-27%), with less than a 1% attributable mortality rate with experienced physicians.

In peritoneal abscess formation caused by subacute bowel perforation (eg, diverticulitis, Crohn disease, appendicitis), primary percutaneous management with percutaneous drainage was successful in most patients. Patients with Crohn disease whose abscesses were drained percutaneously had significantly fewer associated fistulae. Failure in these patients was related to preexisting fistulization and extensive stricture formation.

Concerns regarding the transgression of small or large bowel with drainage catheters in deep abscesses or ileus have been addressed in animal studies, which have found no increase in abscess formation, independent of whether catheters remained for 5 days or longer. Similar data are not available in human patients.

In summary, percutaneous and surgical drainage should not be considered competitive but rather complementary. If an abscess is accessible to percutaneous drainage and the underlying visceral organ pathology does not clearly require an operative approach, percutaneous drainage can be used safely and effectively as the primary treatment modality. In these cases, patients must be closely monitored, and improvement should occur in less than 24-48 hours. With lack of improvement, patients must be reevaluated aggressively (eg, repeat CT scan) and the therapeutic strategy should be altered accordingly.

In general, patients with peritonitis develop some degree of gut dysfunction (eg, ileus) after exploration. Consider establishing some form of nutritional support early in the course of treatment because most patients have an insufficient enteral intake for a variable amount of time preoperatively. The existing data support that enteral nutrition is superior to parenteral hyperalimentation. Enteral nutrition has been found to have fewer complications in patients who are severely ill. If enteral feeding is contraindicated or not tolerated, parenteral nutrition should be instituted.

Nutritional demands increase during sepsis, with caloric requirements of 25-35 kcal/kg/d. Patients with sepsis should be fed a high-protein isocaloric diet. Hypercaloric diets cannot prevent the intense protein catabolism associated with sepsis. ^[28]

The treatment of intra-abdominal sepsis requires a multidisciplinary approach. In the treatment of secondary peritonitis, a surgeon must be consulted. Interventional radiology may need to be consulted if ultrasound or CT-guided drainage of an abscess is being considered.

Other consultations may include the following:

• Gastroenterology

• Infectious disease

• Critical care

• Diet/nutrition

Complications of peritonitis include tertiary peritonitis, infection or dehiscence of the surgical site, enterocutaneous fistula, abdominal compartment syndrome, and enteric insufficiency. Enterocutaneous fistulae can lead to ongoing (potentially large) volume, protein, and electrolyte losses; inability to use the gut for nutritional support; and associated long-term complications of intravenous alimentation. Abdominal compartment syndrome is a well-recognized disease entity related to acutely increased abdominal pressure (ie, intra-abdominal hypertension) and is associated with the development of multiple organ dysfunction. Extensive initial (gastrointestinal) disease, chronic recurrent infections, and associated reoperations may lead to enteric insufficiency because of short gut, pancreatic insufficiency, or hepatic dysfunction.

Outpatient treatment of peritonitis is very limited; however, of the common causes of peritonitis, diverticulitis is probably the entity most frequently treated in an outpatient setting. A review by Biondo et al outlines both inpatient and outpatient therapy. ^[29]

Depending on the type of perforation causing secondary peritonitis, patients may require further surgical care or repeat abscess drainage by interventional radiology. Follow-up care depends on the cause of the intra-abdominal sepsis. In simple infections, such as those caused by cholecystitis or appendicitis, once the infection is cleared, no follow-up care is necessary. However, in patients with perforated duodenal ulcer, chronic pancreatitis, or Crohn disease, lifelong follow-up care is needed.

Repeat paracentesis is not required in spontaneous bacterial peritonitis (SBP) if the patient has advanced cirrhosis with signs and symptoms of infection, a positive bacterial isolate with monomicrobial typical organism, and a good response to treatment. ^[30]  If the course is atypical, repeat paracentesis should be performed in 48 hours.

For SBP, a 10-day to 14-day course of antibiotics is recommended. Although not required, a repeat peritoneal fluid analysis is recommended to verify declining polymorphonuclear neutrophil (PMN) counts and sterilization of ascitic fluid.

If improvement in ascitic fluid or clinical condition does not occur within 48 hours, further evaluation is required to rule out bowel perforation or intra-abdominal abscess. Evaluation may include a combination of radiography, computed tomography scanning, intraluminal contrast studies, or surgical exploration.

After resolution of peritonitis and peritoneal abscesses, follow-up care is directed mostly by specifics of the underlying disease process and the presence or absence of chronic complications (eg, enterocutaneous fistulae). Patients with simple peritoneal infections after appendicitis or cholecystitis are usually cured and do not require long-term follow-up care. Patients with peritoneal operations for perforated peptic ulcer disease, Crohn disease, pancreatitis, and others often require lifelong medical therapy and treatment of recurrent complications.

The prevention of peritonitis centers on causes that are acquired, most of which involve longstanding behaviors that despite all best efforts, remain uncontrolled. Diverticula develop in the Western population with increasing age at a prevalence of 80% in the eighth decade of life. Although increasing fiber and fluid intake has been promoted, the evidence to support this regimen is inadequate.  ^[31]   In cirrhotic patients with ascites, similar results of unclear efficacy of prophylaxis haunt effective prevention.  ^[32]

Outpatient prophylaxis, although not routinely recommended, has been shown to prevent SBP in the following high-risk groups:

• Patients with ascites admitted with acute GI bleeding

• Patients with ascitic fluid protein levels of less than 1 g/dL

• Patients with a prior episode of SBP

Suggested outpatient prophylactic regimens include the following:

• Norfloxacin - 400 mg daily

• Ciprofloxacin - 750 mg weekly

• Five doses of double-strength trimethoprim-sulfamethoxazole per week (Monday through Friday)

Evidence suggests that the long-term prophylaxis of patients with cirrhosis with fluoroquinolones, often norfloxacin, has led to selective intestinal decontamination and high-level fluoroquinolone resistance. This has been supported by published data that show a higher predominance of gram-positive pathogens in ascitic fluid cultures than previously reported. ^[33]