Teaching Case

A 87-year-old man with history of chronic obstructive pulmonary disease (COPD), prostate cancer and cholecystectomy, presented with a 4-day history of intermittent cramping diffuse abdominal pain. Also, he reported two days with constipation and vomiting. Abdominal examination revealed a soft abdomen, diffuse tenderness to light palpation and weak bowel sounds. Rectal exploration shows normal stool. Lab results were unremarkable.

Computed tomography (CT) was performed without contrast media because of renal failure.
CT showed dilated multiple small bowel loops up to 4 cm in the upper and right side of the abdomen. There was extensive air intramural in the small bowel, in the mesentery dissecting the abdominal fat planes as well as pneumoperitoneum (PP). No portal venous gas was observed. Terminal ileum and colon were not dilatated. There was a little amount of free fluid in the pelvis.(Fig. 1, 2). CT of the thorax revealed centrilobular pulmonary emphysema. (Fig. 2)
Exploratory laparotomy was performed and confirmed pneumatosis intestinalis and dilation of small bowel loops due to adherence. No perforation or ischaemia of bowel was found. Adhesiolysis was done without bowel resection. Intraoperative findings were consistent with benign pneumonitis intestinalis (PI) in patients with COPD. The operation went smoothly, and post-operative course was smooth.The patient was discharged in stable condition after a short stay in the hospital.

PI is a radiologic and pathologic finding of a rare condition, which is defined by the presence of gas in the bowel wall. The incidence of PI is 0.03%, but in recent times the incidence has increased to 0.3% due to increased use of advanced imaging technologies and especially CT, which is the most sensitive imaging for detection of PI. [1, 2]
PI can be divided into two general types:
- Primary: not associated with other coexisting diseases.
- Secondary: associated with various conditions including COPD, immunosuppression therapy, steroid usage and inflammatory bowel disease.
PI may be treated conservatively or surgically. The appropriate treatment depends on the underlying cause of PI and the clinical manifestations.It can vary from an incidental finding that is invariably clinically benign, to being severely life-threatening (i.e. ischaemia).
The origin of the air in the bowel wall is still unclear and several theories have evolved to help explain the aetiology.
The mechanical theory hypothesises that gas migrates from the gastrointestinal lumen into the submucosal or subserosal layer of the intestinal wall due to increased intraluminal pressure (i.e. coughing and intestinal obstruction).
The pulmonary theory hypothesises that alveolar rupture could result in the dissection of air along vascular channels in the mediastinum, tracking caudally to the retroperitoneum and then locating within the bowel mesentery. [3, 4]
Since our patient had a history of longstanding COPD but also was found to have adhesions, we assumed that both mechanism were possible in this case.
We assumed that chronic coughing had resulted in alveolar rupture and that the alveolar gas dissects along the aorta into the mesenteric blood vessels, breaching the bowel wall and then becoming trapped.
PP is always an alarming sign. Emergency physicians should be aware of the potential development of PI and associated PP due to ruptured cyst in COPD patients and that the presence of free air in the abdominal cavity is not necessarily caused by hollow organ perforation and/or ischaemia.Therefor carefully taken medical history and clinical examination are mandatory. In such cases conservative treatment yield satisfactory outcomes, while laparotomy should be reserved for life-threatening conditions [1, 3, 5].
In our patient who underwent operation, no perforation or bowel ischaemia was found.
The presence of PP was unclear but assumed to be caused by ruptured cyst of PI or due to dissection of intramural gas through the serosal layer of the bowel.
And the small bowel ileus in this case was due to adhesion resulted from previous cholecystectomy and not related to PI.