Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

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 be localized as an abscess. Peritonitis commonly decreases intestinal motility and causes intestinal distention with gas. With antibiotics, mortality is now 10%, and it's usually due to bowel obstruction.

Causes

·   Chronic liver disease

·   Renal failure

·   Appendicitis, diverticulitis

·   Chronic liver disease

·   Renal failure

·   Peptic ulcer, ulcerative colitis

·   Volvulus, strangulated obstruction

·   Abdominal neoplasm

·   Penetrating trauma, such as a stab wound

·   Rupture of a fallopian tube or the bladder

·   Perforation of a gastric ulcer

·   Released pancreatic enzymes

Pathophysiology

Although the GI tract normally contains bacteria, the peritoneum is sterile. When bacteria or chemical irritants invade the peritoneum due to inflammation and perforation of the GI tract, peritonitis is the result. Accumulated fluids containing protein and electrolytes make the transparent peritoneum opaque, red, inflamed, and edematous. Because the peritoneal cavity is so resistant to contamination, infection is commonly localized as an abscess.

Signs and symptoms

·   Sudden, severe, and diffuse abdominal pain that tends to intensify and localize in the area of the underlying disorder, such as right lower quadrant in appendicitis

·   Acutely tender, distended, rigid abdomen; rebound tenderness

·   Pallor, excessive sweating, cold skin

·   Absent or diminished bowel sounds

·   Nausea, vomiting, abdominal rigidity

·   Signs and symptoms of dehydration (oliguria, thirst, dry swollen tongue, and pinched skin)

·   Temperature of 103 F (39.4 C) or higher

·   Shoulder pain

·   Hypotension

·   Tachycardia

·   Cloudy peritoneal dialysis fluid

Clinical Tip

Abdominal distention and resulting upward displacement of the diaphragm may decrease respiratory capacity. Typically, the patient with peritonitis tends to breathe shallowly and move as little as possible to minimize pain. He may lie on his back, with knees flexed, to relax abdominal muscles.

Diagnostic test results

·   Abdominal X-ray shows edematous and gaseous distention of the small and large bowel or in the case of visceral organ perforation, air lying under the diaphragm.

·   Chest X-ray shows elevation of the diaphragm.

·   Blood studies show leukocytosis.

·   Paracentesis reveals bacteria, exudate, blood, pus, or urine.

·   Laparotomy identifies the underlying cause.

Treatment

Emergency treatment

·   Nothing by mouth—to slow peristalsis and prevent perforation

·   Nasogastric intubation

·   Antibiotics, based on infecting organism

·   Analgesics

·   Parenteral fluids and electrolytes

When peritonitis results from perforation, surgery should be performed as soon as possible to eliminate the source of infection by evacuating the spilled contents and inserting drains.

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GENERALIZED PERITONITIS

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