Secondary peritonitis overview
Synonyms and keywords:: Surgical peritonitis, Perforation peritonitis, Acute peritonitis, Acute bacterial peritonitis, Acute generalized peritonitis, Abscess of suppurative peritonitis, Purulent peritonitis, Chemical peritonitis, Peritoneal abscess.

# Overview
Secondary peritonitis is the most common cause of peritonitis, seen in 80-90% of patients, as a result of inflammation, perforation, or gangrene of an intra-abdominal or retroperitoneal organ. Surgical intervention is typically required to treat these processes. Antibiotics play an adjunctive role in severe intra-abdominal infection. If left untreated, patients with secondary peritonitis usually die due to life-threatening sepsis and shock.

# Definition
Secondary peritonitis is defined as the infection of the peritoneum due to spillage of organisms into the peritoneal cavity resulting from hollow viscus perforation, anastomotic leak, ischemic necrosis, or other injuries of the gastrointestinal tract.

# Historical perspective
- Mikulicz 1889; Kronlein 1885; Korte 1892 reported the surgical treatment of peritonitis.
- Kirschner in 1926 was the first to demonstrate a reduction in mortality rate by surgical treatment from 80100% to about 60% in 1926.

# Classification
Secondary peritonitis is classified based on the etiology and extension of inflammation.

# Pathophysiology
Disturbances in the intestinal mucosal barrier as a result of spontaneous disease, trauma, or surgical operations permit the escape of indigenous bacteria causing infection of the peritoneum.

# Causes

## Causes by source

# Differentiating Secondary peritonitis from other conditions

# Epidemiology and Demographics

# Risk Factors
Risk factors of Secondary peritonitis are numerous intraabdominal disorders involving the gastrointestinal or genitourinary tract with spillage of material into the peritoneal space.

# Natural History, Complications and Prognosis
The prognosis and outcome of patients with postoperative peritonitis is directly related to early diagnosis and stringent treatment interventions along with the complex interaction of factors related to: patient, disease and intervention and the chronic health status. Septicemia, shock and renal failure account for life threatening complications of peritonitis.The mortality of generalized postoperative peritonitis is high at 22-55%. Inability to clear the abdominal infection or to control the septic source, older age, and unconsciousness were significant factors related to mortality. Failure to control the peritoneal infection (15%) increases fatality and correlates with failed septic source control, high Acute Physiology and Chronic Health Evaluation (APACHE) II score, and male gender. Failure to control the septic source (8%) also was always fatal and correlated with high APACHE II score and therapeutic delay. In patients with immediate source control, residual peritonitis occurred in 9% after purulent or biliary peritonitis and in 41% after fecal peritonitis. In patients without immediate control of the septic source, delayed control was still achieved in 100% after a planned relaparotomy (PR) strategy versus 43% after an on-demand relaparotomy (ODR). 

# Diagnosis
Diagnostic criteria for peritonitis associated with perforation on the basis of the initial ascitic fluid analysis include fulfilling at least two of the following criteria:
- Total protein > 1 g/dl
- Glucose < 50 mg/dl
- Lactate dehydrogenase (LDH) greater than the upper limit of normal for serum.
Non perforated secondary peritonitis such as perinephric abscess, cannot be readily apparent on the basis of the initial ascitic fluid analysis, but the response of the ascitic fluid cell count and cultures to treatment can raise suspicion of this form of secondary peritonitis.

## History and Symptoms
The clinical picture of peritonitis is determined by the nature of the causative lesion, duration and extension of the inflammatory process, and stage of the disease.

## Physical Examination
The main manifestations of peritonitis are acute abdominal pain, tenderness, and guarding, which are exacerbated by moving the peritoneum, e.g. coughing, flexing the hips, or eliciting the Blumberg sign (a.k.a. rebound tenderness, meaning that pressing a hand on the abdomen elicits pain, but releasing the hand abruptly will aggravate the pain, as the peritoneum snaps back into place). Abdominal rigidity, generalized peritonitis (versus localized), hypotension, tachycardia and anemia were significantly associated with mortality.

## Laboratory Findings
As the clinical signs and symptoms are not a good representation for the diagnosis of secondary peritonitis, initial ascitic fluid analysis and the response of ascitic fluid parameters to treatment have been found to be of great value in differentiating secondary peritonitis from spontaneous bacterial peritonitis.

## Chest X Ray
An upright and supine plain films of the chest and abdomen should be performed in patients with abdominal pain to exclude free air under the diaphragm (most often on the right), which signals a bowel perforation and associated peritonitis.

## CT Scan
CT may be positive in unto 82%. Indicated in all patients with acute abdomen. However, CT can be omitted when a diagnosis is made according to the results of precedent examinations such as Ultrasound. Radiation exposure should be considered with the use of CT.

## Ultrasound
Ultrasound may be positive in unto 72%. It is recommended as a screening test for acute abdomen and strongly recommended particularly when abdominal aortic aneurysm rupture or acute cholecystitis is suspected. Ultrasound is recommended in pregnant women, young women or children in whom radioactive exposure is not desirable.

## Diagnostic Evaluation of Secondary Peritonitis

# Treatment

## Medical Therapy
Medical management of secondary peritonitis includes hydration, prevention of septicemia, and correction of electrolytes. Empiric coverage for gram positive, gram negative, and anaerobic bacteria should be initiated promptly while awaiting culture results. Either open abdominal surgery or an exploratory laparotomy is recommended.

## Surgery
The surgical treatment of postoperative peritonitis is primarily aimed at defining source control, followed by debridement of fibrin bedding and abdominal lavage of contaminants and infectious fluids. In cases of suspected diffuse secondary peritonitis, indication for relaparotomy after positive findings in CT were based on the following citeria: Evidence of leakage, intraabdomnal air after more than five days postoperatively, and/or massive collection of intraabdominal fluid. Re-laparotomy has to be performed immediately following positive radiological examination and/or clinical/laboratory signs. In postoperative peritonitis, negative radiological findings and persistent symptoms of sepsis for longer than 24 hours were also indications for relaparotomy.

## Prevention