Sandbox:peritonitis

Definition

Peritonitis defined as the inflammation of the peritoneum from any cause which lines abdominal cavity and the internal organs as a serosal membrane. Contrast to peritonitis, Intrabdominal infection is defined as the inflammation of peritoneum due to infectious cause.

Primary or Spontaneous Peritonitis

Primary peritonitis is defined as the infection of the peritoneal cavity which is spontaneous and often associated with liver disease and ascites. It is also known as spontaneous bacterial peritonitis. Primary peritonitis lacks an identifiable anatomical derangement.

Secondary Peritonitis

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.

Tertiary Peritonitis

Tertiary peritonitis is defined as the persistant or recurrent intra-abdominal infection that occur in ≥48 hours following the successful and adequate surgical source control of primary or secondary peritonitis.

Bacterascitis

Bacterascites is defined as the presence of culture positivity without increase in PMN count in the ascitic fluid.

Historical Perspective

The first reports describing this entity appeared in the German and French literatures between 1907 and 1958. Spontaneous bacterial peritonitis was first described by Krencker in 1907 followed by Caroli in 1958 and Kerr and colleagues in 1963. The term 'spontaneous bacterial peritonitis' was coined by Conn in 1964 to depict a syndrome of peritonitis and bacteremia in Laennec’s cirrhosis without an apparent cause of infection.

Classification

Peritonitis is classified based on the etiology as follows:

Peritonitis

Primary peritonitis

Secondary peritonitis

Tertiary peritonitis

❑ Spontaneous peritonitis ❑ Peritonitis in patients with CAPD ❑ Tuberculous peritonitis

❑ Peritonitis without evidence for pathogens ❑ Peritonitis with fungi ❑ Peritonitis with low-grade pathogenic bacteria

Acute perforation peritonitis ❑ Gastrointestinal perforation ❑ Intestinal ischemia ❑ Pelviperitonitis and other forms

Postoperative peritonitis ❑ Anastomotic leak ❑ Accidental perforation and devascularization

Post-traumatic peritonitis ❑ After blunt abdominal trauma ❑ After penetrating abdominal trauma

Pathogenesis

Patent with signs and symptoms suggestive of peritonitis ❑ Abdominal pain ± guarding or rebound ❑ Fever, leukocytosis ❑ Signs of sepsis (hypotension, tachycardia, etc. Signs and symptoms may be equivocal or attenuated in: ❑ Patients with diabetes or other immune compromising conditions ❑ Elderly patients ❑ Patients with ascites(Cirrhosis or nephrotic syndrome) ❑ Patients on peritoneal dialysis ❑ Patents on corticosteroid medication

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Peritonitis can be regarded as the localized event after any trigger of inflammation similar to the systemic inflammatory response(SIRS).

Primary peritonitis

As the primary disease (e.g. cirrhosis) progresses, gram negative bacteria increase in numbers in the gut. Once bacteria reach a critical concentration in the gut lumen, they will translocate into the mesenteric lymphatic system because of the failure of the gut to contain bacteria and failure of the immune system to kill the virulent bacteria once they have escaped the gut result in bacteremia and endotoxinemia.

Secondary peritonitis develops perforation of intra abdominal organs when bacteria contaminate the peritoneum as a result of spillage from an intraabdominal viscus. The organisms found almost always constitute a mixed flora in which facultative gram-negative bacilli and anaerobes predominate, especially when the contaminating source is colonic.

Causes

Common Causes

Primary Peritonitis	Secondary Peritonitis	Tertiary Peritonitis
Cirrhosis with ascitis Portal hypertension with ascitis Renal failure patient with continuous ambulatory peritoneal dialysis (CAPD)	Ruptured gastric ulcer, appendicular abscess or diverticular abscess Inflamatory bowel diseases such as chron's disease or ulcerative colitis with toxic megacolon Pelvic inflamatory disease Recent surgical procedures Recent trauma to the abdomen (e.g. Stab injury or gun shot injury)	Previous history of severe antibiotic use Treatment failure in patients with primary or secondary peritonitis

Epidemiology

SBP is the most frequent bacterial infection in cirrhosis, accounting for 10-30% of all reported bacterial infections in hospitalised patients.

The prevalence of SBP in outpatient setting asymptomatically is low (< 3.5% ), but the prevalence increases to 8%-36% in the nosocomial setting.

Mortality rate for the first episode of SBP in in-patient setting varies between 10-50%, depending upon the risk factors. One-year mortality after a first episode of SBP has been reported to be 31% and 93%.

Diagnosis

Identification of risk factors and individualisation of timing and selection of prophylactic measures are the key to success without major development of resistant bacteria.

Varient of Spontaneous bacterial peritonitis (SBP)	Ascitic fluid analysis and other information
SBP culture postive	PMNs ≥250 cells/mm3 and culture positivity Patients with cirrhosis and ascites in the presence or absence of symptoms and signs
Culture-negative neutrocytic ascites(CNNA) or culture-negative SBP	PMNs ≥250 cells/mm3 and culture negativity Poor culture technique and prior antibiotics or low opsonic activity in ascitic fluid. Commonly encountered phenotype and requires antibiotic therapy
Monomicrobial bacterascites	PMNs <250 cells/mm3 and culture positivity Ascitic fluid infection which may resolve spontaneously or progress to SBP. Similar mortality to SBP and should be treated the same
Other varieties of ascitic fluid infections	Ascitic fluid analysis and other information
Polymicrobial bacterascites	PMNs <250 cells/mm3 and culture positivity Needle perforation
Secondary peritonitis	PMNs ≥250 cells/mm3 and culture positivity Intraperitoneal source of infection, e.g. diverticulitis

Treatment

Empirical treatment for peritonitis
Primary Peritonitis	Secondary Peritonitis	Peritonitis related to peritoneal dialysis
Ceftriaxone 1gm IV Q12H x 5days Penicillin allergic patients: Moxifloxacin 400mg IV/PO Q24H x 5days Patient with serum creatinine >1mg/dl, BUN >30mg/dl or total bilurubi >4mg/dl should also receive Albumin25% 1.5g/kg on day 1 and 1gm/kg on day 3 (round to the nearest 12.5gm) Duration: 5days	Mild or moderate secondary peritonitis Ertapenem 1gm IV Q24H Penicillin allergic patients: Ciprofloxacin 400mg IV Q12H + Metronidazole 500mg IV Q8H Severe peritonitis or Immunocompromised patients Piperacillin/ tazobactam 3.375gm IV Q6H Penicillin allergic patient: Cefepime 1gm IV Q8H + Metronidazole 500gm IV Q8H Severe PCN allergic patient: Vancomycin + Aztreonam 1gm IV Q8H or Ciprofloxacin 400mg IV Q8H + Metronidazole 500mg IV Q8H Duration of empiric therapy depends on whether the peritonitis is complicated or uncomplicated: Uncomplicated: Perforation is operated with in 12-24 hours Duration of empiric therapy: 24-48 Complicated: Perforation is operated lately or necrotic/gangrenous appendix is developed. Duration of empiric therapy: 4 days unless adequate source control is not achieved.	Mild or moderate secondary peritonitis Intraperitoneal therapy is preferred Anuric patient Cefazolin 15mg/kg in one bag + Gentamicin 2mg/kg in one bag loading dose, then Gentamicin 0.6mg/kg in one bag Q24H Patient with urine output > 100ml/day Ceftazidime 1gm in one bag Q24H Sever illness Systemic therapy is preferred. Initial dose: Vancomycin + Gentamicin 2mg/kg or Ceftazidime 1gm IV or Ciprofloxacin 400mg IV Maintainance dose: dosage level depending on renal funtion Duration: 10-14days
Empiric antifungal therapy
Emperical antifungal therapy is generally indicated in secondary peritonitis excepet if the patient has one of the following risk factors: Esophageal perforation Immunosuppression Prolonged antacid therapy Prolonged antibiotic therapy Prolonged hospitalization Persistant GI leak If the patient is clinically stable and no history of prior long term azole therpy: Fluconazole 400-800 mg IV/PO Q24H If the patient is clinically unstable or patient with history of prior long term azole therpy: Micafungin 100mg IV Q24H

Primary Peritonitis

The flora of primary peritonitis is typically monomicrobial.

Secondary Peritonitis

Treatment of secondary peritonitis depends on the etiological factor and effective therapy includes cause specific surgical intervention and adjunctive antibiotic therapy.

Prevention

Prophylaxis is of crucial relevance when trying to improve survival.