Editing Peritonitis

Inflammation of the peritoneum.

== '''Nomenclature''' ==

* Intra-abdominal infection: intraperitoneal presence of micro-organisms, and the inflammatory response

* Peritoneal contamination: micro-organisms, but no inflammatory response

* Abdominal sepsis: not a very descriptive term, but implies systemic host response to intra-abdominal infection

== '''Aetiology''' ==

* Generally caused by bacterial inoculation

== '''Pathophysiology''' ==

* '''Primary peritonitis:''' originates from a source outside the abdomen, including dialysis catheters
** Extremely rare without a known predisposing factor
** Typically single organism
*** ''Streptococcus'' through genital tract in young girls
*** ''E coli'' in spontaneous bacterial peritonitis affective pre-existing ascites from cirrhosis
*** ''Staphylococcus'' through a peritoneal dialysis catheter
** Seen on presentation as an acute abdomen with free fluid on CT but no obvious source
** Diagnosis via paracentesis (polymorphonuclear count in ascitic fluid > 250 cells per cubic mm
** Avoid diagnostic exploratory laparoscopy or laparotomy because of its prohibitive mortality
* '''Secondary peritonitis:''' caused by a breach in the anatomical integrity of a hollow viscus
** Usually aerobic and anaerobic polymicrobial inoculation, reflecting GIT flora
* '''Tertiary peritonitis''': the end stage of high-risk intra-abdominal infection
** Becoming less-frequently described and less useful as a clinical descriptor
** Seen in an ICU patient with multi-organ dysfunction, who has survived peritonitis through aggressive source control but has an open abdomen, and now the peritoneal cavity contains a thin, cloudy, poorly walled-off exudate which grows opportunistic micro-organisms
** An outcome of unsuccessful treatment of bacterial peritonitis
** Frequently fatal outcomes

== '''Management''' ==

* '''Approach'''
** Risk classification: assess premorbid reserves, current physiological compromise and virulence of infection
** Adjunctive measures
** Source control
** Peritoneal toilet
* '''Risk classification'''
** High risk: hospital-acquired infections; post-operative infections; critically ill or immunocompromised
*** Needs tailored antibiotics
*** Source control can be very hard
*** Poor prognosis
** Low risk: community-acquired (perforated appendicitis or diverticulitis etc); not physiologically compromised; pre-morbidly healthy
*** Standard broad-spectrum antibiotics
*** Source control will be easy
*** Good prognosis
* '''Adjunctive measures'''
** Resuscitation
** Monitoring
** Antibiotics
*** Empirical is ok - don't need peritoneal cultures in patients with community-acquired, low-risk peritonitis; but should be obtained in the following situations:
**** High-risk peritonitis
**** Already been on antibiotics
**** Previous resistant organism
**** Suspected primary peritonitis
**** Tertiary peritonitis
* '''Source control'''
** Doesn't necessarily mean an operation - match the intervention to the individual patient
** Use the least invasive approach that can achieve source control
** Temporisation if there is major physiological compromise, but otherwise as soon as possible
* '''Peritoneal toilet''' (if operating)
** Remove liquid contaminants and infected exudates
** Irrigate with warm crystalloids
** Rationalise use of drains - evacuate established abscesses, allow escape of potential secretions, or establish a controlled intestinal fistula
* '''Recognise treatment failure'''
** Ongoing or increasing sepsis for more than 24-48 hours suggests that the initial source control was inadequate

[[Category:Critical care]]