In a minority of cases, the identification of pneumoperitoneum on imaging is not an indication for emergency surgery, particularly when the patient has no signs of peritoneal irritation. A 59-year-old man presented after 5 days of nausea, vomiting, and mildly painful abdominal distention. He had a 6-year history of scleroderma, marked by Raynaud phenomenon, characteristic skin-tightening, and high titers of antinuclear antibodies. His vital signs were stable and bowel sounds were present, but his abdomen was diffusely distended, and he had mild epigastric tenderness without rebound or guarding.
Assessment
An abdominal radiograph, obtained while the patient was in the supine position, showed dilated bowel loops and a double wall sign. Another, taken while the patient was upright, revealed an air-fluid level and pockets of free air. Computed tomography demonstrated innumerable air pockets in the submucosal and subserosal layers of the bowel wall; these were associated with free air in the peritoneal space—pneumoperitoneum—and a small amount of free fluid. Nonetheless, the patient remained only moderately uncomfortable.
Diagnosis
The patient’s clinical and radiographic presentation led to a diagnosis of pneumatosis cystoides intestinalis and pneumoperitoneum, secondary to his scleroderma. The gastrointestinal tract is the second most common site of complications among patients with scleroderma, but pneumatosis cystoides intestinalis, the presence of multiple air-filled cysts within the intestinal wall, is rarely seen. The phenomenon was first described in 1730 by Du Vernoi. It has been documented in patients with rheumatic, obstructive lung, or gastrointestinal diseases, malignancy, conditions requiring immunosuppressant therapy, or iatrogenic injury. While the cause and pathogenesis have yet to be identified, theories do exist, and possibly a combination of these will provide an answer.2 For example, the bacterial theory suggests that bacterial overgrowth and fermentation could cause gaseous distention of the intestine, leading to increased intraluminal pressure and accumulation of gas in the intestinal wall. Ruptured intraluminal cysts may result in pneumoperitoneum. Chemical, mechanical, and pulmonary theories are also under consideration.
Imaging does not distinguish between benign and life-threatening sources of pneumoperitoneum, thus, clinical information is crucial. As our patient’s abdominal complaints were mild despite suspected bowel obstruction, conservative management was undertaken.
Management
Conservative treatment with prokinetic agents and rotating courses of antibiotics is commonly employed. Parenteral nutrition can occasionally be required in severe cases. Our patient’s supportive management included nasogastric suction, bowel rest, and administration of oral metronidazole. He recovered in 2 weeks.
Pneumatosis cystoides intestinalis can be complicated by bowel obstruction, in which case, exploratory laparotomy can be undertaken, but intestinal necrosis is uncommon in this disorder. Our patient’s case illustrates that conservative management is often sufficient when minimal signs and symptoms of ileus, without evidence for bowel perforation, ischemia, or necrosis, are noted at presentation.
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-Mitsuyo Kinjo, MD, MPH
This article originally appeared in the April 2016 issue of The American Journal of Medicine.
