Porth's Essentials of Pathophysiology, 4e

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Gastrointestinal and Hepatobiliary Function

U N I T 8

A

Small intestine Peritoneum Hernial sac Testicle

B

C

FIGURE 29-10. Three causes of intestinal obstruction. (A) Intussusception with invagination or shortening of the bowel caused by movement of one segment of the bowel into another. (B) Volvulus of the sigmoid colon; the twist is counterclockwise in most cases. Note the edematous section of bowel. (C) Hernia (inguinal).The sac of the hernia is a continuation of the peritoneum of the abdomen.The hernial contents are intestine, omentum, or other abdominal contents that pass through the hernial opening into the hernial sac. (From Smeltzer SC, Bare BG. Brunner and Suddarth’sTextbook of Medical–Surgical Nursing. 10th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2004:1055.)

necrosis and movement of blood into the luminal flu- ids. This promotes rapid growth of bacteria, especially anaerobes that grow rapidly in this favorable environ- ment and produce a lethal endotoxin. 54 The manifestations of intestinal obstruction depend on the degree of obstruction and its duration. The major symptoms of acute intestinal obstruction are pain, abso- lute constipation, abdominal distention, and vomiting. 51 With mechanical obstruction, the pain is severe and colicky, in contrast with the continuous pain and silent abdomen of paralytic ileus. There also is borboryg- mus (i.e., rumbling sounds made by propulsion of gas in the intestine); audible, high-pitched peristalsis; and peristaltic rushes. Visible peristalsis may appear along the course of the distended intestine. Extreme restless- ness and conscious awareness of intestinal movements are experienced along with weakness, perspiration, and anxiety. Should strangulation of the bowel occur, there is a change in symptoms. The character of the pain shifts from the intermittent colicky pain caused by the hyper- peristaltic movements of the intestine to a severe and steady type of pain. Vomiting and fluid and electrolyte disorders occur with both types of obstruction. Diagnosis of intestinal obstruction usually is based on history and physical findings. Plain film radiography

of the abdomen may be used to detect the presence of a gas-filled bowel. CT scans and ultrasonography may also be used to detect the presence of mechanical obstruction. 51 Treatment depends on the cause and type of obstruction. Most cases of adynamic obstruction respond to decompression of the bowel through naso- gastric suction and correction of fluid and electrolyte imbalances. Strangulation and complete bowel obstruc- tion require surgical intervention. Peritonitis Peritonitis is an inflammatory response of the serous membrane that lines the abdominal cavity and covers the visceral organs. 6 It can be caused by bacterial inva- sion or chemical irritation. Most commonly, enteric bacteria enter the peritoneum because of a break in the wall of one of the abdominal organs. The most common causes of peritonitis are perforated peptic ulcer, ruptured appendix, perforated diverticulum, gangrenous bowel, pelvic inflammatory disease, and gangrenous gallblad- der. Other causes are abdominal trauma and wounds. The peritoneum has several characteristics that increase its vulnerability to or protect it from the effects