Peritonitis

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Peritonitis
ICD-10	K65
ICD-9	567
DiseasesDB	9860
MeSH	D010538

Peritonitis Main Page
Patient Information
Overview
Causes
Classification Spontaneous Bacterial Peritonitis Secondary Peritonitis
Differential Diagnosis

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Mechanisms & manifestations

Abdominal pain & tenderness

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). The localisation of these manifestations depends on whether peritonitis is localised (e.g. appendicitis or diverticulitis before perforation), or generalised to the whole abdomen; even in the latter case, pain typically starts at the site of the causing disease. Peritonitis is an example of acute abdomen.

Collateral manifestations

• Diffuse abdominal rigidity ("washboard abdomen") is often present, especially in generalised peritonitis;
• Fever;
• Sinus tachycardia;
• Development of ileus paralyticus (i.e. intestinal paralysis), which also causes nausea and vomiting;

Complications

• Sequestration of fluid and electrolytes, as revealed by decreased central venous pressure, may cause electrolyte disturbances, as well as significant hypovolaemia, possibly leading to shock and acute renal failure.
• A peritoneal abscess may form (e.g. above or below the liver, or in the lesser omentum).
• Sepsis may develop, so blood cultures should be obtained.

• the fluid may push on the diaphragm and cause breathing difficulties

Diagnosis and investigations

A diagnosis of peritonitis is based primarily on clinical grounds, that is on the clinical manifestations described above; if they support a strong suspicion of peritonitis, no further investigation should delay surgery. Leukocytosis and acidosis may be present, but they are not specific findings. Plain abdominal X-rays may reveal dilated, oedematous intestines, although it is mainly useful to look for pneumoperitoneum (free air in the peritoneal cavity), which may also be visible on chest X-rays. If reasonable doubt still persists, an exploratory peritoneal lavage may be performed (e.g. in cause of trauma, in order to look for white blood cells, red blood cells, or bacteria).

Treatment

Depending on the severity of the patient's state, the management of peritonitis may include:

• General supportive measures such as vigorous intravenous rehydration and correction of electrolyte disturbances.
• Antibiotics are usually administered intravenously, but they may also be infused directly into the peritoneum. The empiric choice of broad-spectrum antibiotics often consist of multiple drugs, and should be targeted against the most likely agents, depending on the cause of peritonitis (see above); once one or more agents are actually isolated, therapy will of course be targeted on them.
• Surgery (laparotomy) is needed to perform a full exploration and lavage of the peritoneum, as well as to correct any gross anatomical damage which may have caused peritonitis. The exception is spontaneous bacterial peritonitis, which does not benefit from surgery.

Prognosis

If properly treated, typical cases of surgically correctable peritonitis (e.g. perforated peptic ulcer, appendicitis, and diverticulitis) have a mortality rate of about <10% in otherwise healthy patients, which rises to about 40% in the elderly, and/or in those with significant underlying illness, as well as in cases that present late (after 48h). If untreated, generalised peritonitis is almost always fatal.

Pathology

The peritoneum normally appears greyish and glistening; it becomes dull 2-4 hours after the onset of peritonitis, initially with scarce serous or slightly turbid fluid. Later on, the exudate becomes creamy and evidently suppurative; in dehydrated patients, it also becomes very inspissated. The quantity of accumulated exudate varies widely. It may be spread to the whole peritoneum, or be walled off by the omentum and viscera. Inflammation features infiltration by neutrophils with fibrino-purulent exudation.

Additional Resources

• Peritonitis disease causes, treatment ...
• All Refer Health article on peritonitis
• Genuit T and Napolitano L. 2004. Peritonitis and Abdominal Sepsis. Emedicine.com
• Health square. 2004. Peritonitis.

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