Acute peritonitis

Acute peritonitis may be localised or general.

Localized peritonitis:

• There is virtually always some degree of localized peritonitis with all acute inflammatory conditions of the GI tract.

• Pain and tenderness are largely features of this localized peritonitis.

• Rx is of the underlying disease.

General peritonitis:

• Serious condition resulting from irritation of the peritoneum

• Caused by:

• Infection (e.g. perforated appendix)

• Chemical irritation due to leakage of intestinal contents (e.g. perforated ulcer)

• The peritoneal cavity becomes acutely inflamed with production of an inflammatory exudate that spreads throughout the peritoneum leading to intestinal dilatation and paralytic ileus.

Clinical features:

1. When the peritonitis is due to perforation:

• Sudden onset

• General collapse

• Shock

• Pt may improve temporarily, only to deteriorate later as generalized toxaemia develops

2. When the peritonitis is secondary to inflammatory disease:

• Onset is less rapid

• Initial features being that of the underlying disease

Investigations:

• Erect CXR (to detect free air under the diaphragm)

• Serum amylase (to dx acute pancreatitis)

• US or CT is becoming popular for dx.

Mx:

• Peritonitis is always rx surgically after adequate resuscitation with the re-establishment of a good urinary output

• Insertion of a NG tube

• IV fluids

• A/Bs

Surgical mx:

Is two-fold:

1. Peritoneal lavage of the abdominal cavity

2. Specific rx if the underlying condition

Complications:

• Delays in rx produces more profound toxaemia and septicaemia

• Local abscess formation can occur and should be suspected if the pt continues to remain unwell post-op with a:

• Swinging fever

• High WCC

• Continuing pain

• Abscesses are typically pelvic or subphrenic. Rx is with drainage and A/Bs.