THE PERITONEUM, OMENTUM, MESENTERY AND RETROPERITONEAL SPACE

THE PERITONEUM, OMENTUM, MESENTERY AND RETROPERITONEAL SPACE
THE PERITONEUM
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Functions of the peritoneum
? Pain perception (parietal peritoneum)
? Visceral lubrication
? Fluid and particulate absorption
? Inflammatory and immune responses
? Fibrinolytic activity

The parietal portion is richly supplied with nerves and, when irritated, causes severe pain accurately localised to the affected area. The visceral peritoneum, in contrast, is poorly supplied with nerves and its irritation causes vague pain that is usually located to the midline.
During expiration, intra-abdominal pressure is reduced and peritoneal fluid, aided by capillary attraction, travels in an
upward direction towards the diaphragm.. This upward movement of peritoneal fluids is responsible for the occurrence of many subphrenic abscesses.
When a visceral perforation occurs, the free fluid that spills into the peritoneal cavity runs downwards, largely directed by the
normal peritoneal attachments. For example, spillage from a perforated duodenal ulcer may run down the right paracolic
gutter.
Summary box 58.2
Causes of a peritoneal inflammatory exudate
? Bacterial infection, e.g. appendicitis, tuberculosis ? Chemical injury, e.g. bile peritonitis ? Ischaemic injury, e.g. strangulated bowel, vascular occlusion ? Direct trauma, e.g. operation ? Allergic reaction, e.g. starch peritonitis
Summary box 58.1
ACUTE PERITONITIS
Most cases of peritonitis are caused by an invasion of the peritoneal cavity by bacteria, so that when the term ‘peritonitis’ is
used without qualification, bacterial peritonitis is implied. Bacterial peritonitis is usually polymicrobial, both aerobic and
anaerobic organisms being present. The exception is primary peritonitis (‘spontaneous’ peritonitis), in which a pure infection
with streptococcal, pneumococcal or Haemophilus bacteria occurs.
Bacteriology