Peritonitis
Peritonitis is inflammation and usually infection of the abdominal cavity and its lining.
Peritonitis is usually caused by an infection spreading from an infected organ in the abdominal cavity. Common sources are perforations of the stomach, intestine, gallbladder, or appendix. Infection can also spread to the peritoneum from other parts of the body through the blood. The peritoneum (the membrane that lines the abdominal cavity and organs) is remarkably resistant to infection. Unless contamination continues, peritonitis does not progress, and the peritoneum tends to heal with treatment.
Pelvic inflammatory disease (see Section 22, Chapter 248) in sexually active women is a common cause of peritonitis. An infection of the uterus and fallopian tubes--which may be caused by several types of bacteria, including the ones that cause gonorrhea and chlamydial infection--spreads into the abdominal cavity.
Peritonitis can develop after surgery for several reasons. An injury to the gallbladder, ureter, bladder, or intestine during an operation can spill bacteria into the abdominal cavity. Leakage also can occur during operations in which intestinal segments are joined.
Peritoneal dialysis (a treatment for kidney failure) frequently results in peritonitis. The usual cause is an infection gaining access through the drains placed in the abdominal cavity. In liver or heart failure, fluid may accumulate in the abdominal cavity (ascites) and become infected.
Peritonitis can also result from irritation of abdominal organs without any infection. For example, inflammation of the pancreas (acute pancreatitis) can produce peritonitis. Also, talc or starch on a surgeon's gloves can cause inflammation of the peritoneum without infection.
Spontaneous peritonitis occurs in people with an accumulation of fluid in their abdomen (ascites). Many such people have liver disease, often from alcohol abuse. Infection of the fluid occurs without an obvious source.
Symptoms
Usually, vomiting, a fever (100.5° F [38.0° C] or higher), and abdominal tenderness occur. Other symptoms depend on whether infection follows inflammation and on the type and extent of the infection. Pain may be limited to a small area of the abdomen or may be present throughout the abdomen. Abdominal pain is usually severe.
Unless peritonitis is treated promptly, complications develop rapidly. One or more pus-filled pockets (abscesses) may form, and the infection can leave scar tissue that eventually may obstruct the intestine. The normal propulsion of stool through the intestines (peristalsis) stops (ileus). Fluid leaks from the bloodstream into the abdominal cavity. Severe dehydration develops, and the bloodstream loses electrolytes (such as sodium and potassium). Major complications--such as lung, kidney, or liver failure and widespread clotting--can follow.
Diagnosis
Rapid diagnosis is crucial. X-rays are taken with the person lying down and standing. Free gas in the abdominal cavity can be seen on x-rays and indicates a rupture. Occasionally, a needle is used to withdraw fluid from the abdominal cavity so that laboratory personnel can detect and identify any infectious organism and test its sensitivity to various antibiotics. This procedure is relatively simple and is done while the person sits up or lies in bed. The most reliable means of diagnosis, however, is exploratory surgery.
Treatment
Usually, the first step is emergency exploratory surgery, particularly when appendicitis, a pierced (perforated) peptic ulcer, or diverticulitis seems likely. When the cause is thought to be inflammation of the pancreas (acute pancreatitis), pelvic inflammatory disease in women, or spontaneous peritonitis, emergency surgery usually is not performed.
Antibiotics, often several at once, are given promptly. Also, a tube may be inserted through the nose and into the stomach or intestine to drain fluid and gas. Fluids and electrolytes may also be given intravenously to replace those that have been lost.
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