• In most cases of perforation, gastric and duodenal content leaks into the peritoneum.
• This content includes gastric and duodenal secretions, bile, ingested food, and swallowed bacteria.
• The leakage results in peritonitis, with an increased risk of infection and abscess formation.
• Subsequent third-spacing of fluid in the peritoneal cavity due to perforation and peritonitis leads to inadequate circulatory volume, hypotension, and decreased urine output.
• In more severe cases, shock may develop.
• Abdominal distension as a result of peritonitis and subsequent ileus may interfere with diaphragmatic movement, impairing expansion of the lung bases.
• Eventually, atelectasis develops, which may compromise oxygenation of the blood, particularly in patients with coexisting lung disease.