Peritonitis - GI presentations

Peritonitis

Definition

Peritonitis is inflammation of the peritoneal lining of the abdomen. Peritonitis may be acute or chronic, primary or secondary.

Aetiology/pathophysiology

Infection can reach the peritoneal cavity from penetrating trauma or surgery, from the abdominal viscera, from the female genital tract or as a result of a septicaemia.

·        Primary acute peritonitis is rare: It is most commonly due to Escherichia coli: Bacteria are thought to be transferred from the gut or bloodstream. Patients undergoing peritoneal dialysis are at particular risk of recurrent acute peritonitis, which may result in fibrosis and scarring preventing further use of this type of dialysis. Chronic liver disease patients with ascites are at risk of developing a less symptomatic form called spontaneous bacterial peritonitis.

·        Chronic infective peritonitis occurs from tuberculous peritoneal infections.

·        The most common type of peritonitis is acute suppurative secondary to visceral disease.

·        Postoperative peritonitis may result from persistence of infection present at the time of surgery or from complications such as anastomotic breakdown.

Clinical features

Peritonitis presents with pain, tenderness, rebound tenderness and excessive guarding. Movement exacerbates the pain, so patients often lie very still and have a rigid abdomen on attempted palpation (stiff as a board).

Complications

Infection may spread to the blood stream (septicaemia) form subphrenic or subhepatic abscesses.

Microscopy

An acute inflammatory exudate is seen with cellular infiltration of the peritoneum.

Investigations

The diagnosis is clinical, further investigation depends on the possible underlying cause.

Management

Management in secondary peritonitis is aimed at prompt surgical treatment of the underlying cause (after aggressive resuscitation). Primary or postoperative peritonitis, which is non-surgical in origin, is managed medically.

·        Nil by mouth, i.v. fluids and nasogastric tube with aspiration (drip and suck).

·        Broad-spectrum antibiotics.

·        Drainage of any abscess or collection (either surgically or ultrasound guided aspiration).