Peritonitis

Peritonitis is an acute or chronic inflammation of the peritoneum, the membrane that lines the abdominal cavity and covers the visceral organs. Inflammation may extend throughout the peritoneum or may be localized as an abscess.

Peritonitis commonly decreases intestinal motility and causes intestinal distention with gas. Mortality is 10%, with death usually resulting from bowel obstruction; the mortality was much higher before the introduction of antibiotics.

Causes

Most often, peritonitis is caused by the introduction of an infection from a perforation of the bowel such as a ruptured appendix or diverticulum. Other sources include perforations of the stomach, intestine, gallbladder, or appendix. Pelvic inflammatory disease in sexually active women is also a common cause of peritonitis. Peritonitis can also develop after surgery when bacteria can enter into the abdomen during an operation.

Signs and symptoms

The signs and symptoms of peritonitis include:

• Swelling and tenderness in the abdomen; pain can range from dull aches to severe, sharp pain causing board-like rigidity
• Fever and chills
• Loss of appetite
• Nausea and vomiting
• Increased breathing and heart rates
• Shallow breaths
• Low blood pressure
• Limited urine production
• Inability to pass gas or feces

Diagnosis

Severe abdominal pain in a patient with direct or rebound tenderness suggests peritonitis. Abdominal X-rays showing edematous and gaseous distention of the small and large bowel support the diagnosis. In the case of perforation of a visceral organ, the radiography film shows air in the abdominal cavity.

Other tests include the following:

• Chest X-ray may show elevation of
  the diaphragm.
• Blood studies reveal leukocytosis (> 20,000/µ1).
• Paracentesis reveals bacteria, exudate, blood, pus, or urine.
• Laparotomy may be necessary to identify the underlying cause.

Treatment

Early treatment of GI inflammatory conditions and preoperative and postoperative antibiotic therapy help prevent peritonitis. After peritonitis develops, emergency treatment must combat infection, restore intestinal motility, and replace fluids and electrolytes.

Antibiotics and supplementary treatment

Empiric antibiotic therapy usually includes administration of cefoxitin with an aminoglycoside or penicillin G and clindamycin with an aminoglycoside, depending on the infecting organisms. To decrease peristalsis and prevent perforation, the patient should receive nothing by mouth; I. V. fluids are administered. Other supportive measures include preoperative and postoperative administration of analgesia and nasogastric (NG) decompression.

Surgery

When peritonitis results from perforation, surgery is necessary. The aim of surgery is to eliminate the source of infection by evacuating the spilled contents and repairing any organ perforation.

Prevention

Prevention depends on the cause. See the specific types of peritonitis.