Teaching Case

A 66-year-old female patient presenting with generalised abdominal pain, nausea, and vomiting. Mild tenderness on abdominal palpation with tympanic sounds on percussion. Previous examination: abdominal US showing a marked gastric dilatation. Risk Factors: non-smoker, no alcohol abuse, no cancer history.

Two projection abdominal radiography shows a large amount of sub-diaphragmatic free gas causing a rise of the diaphragm. Associated gaseous dilation of the abdominal viscera, more evident in the left quadrants, with radiolucent cystic gas collections located along with intestinal loops (Fig. 1).

Triphasic CT scan (basal, arterial, and venous phases):  a large amount of intra-abdominal free air was detected in supra- and sub-mesocolic spaces and in the para- and retro-duodenal areas. Intramural small bowel gas and air within the mesentery, suggestive for Pneumatosis Cystoides Intestinalis, is illustrated in Fig 2.
Fig. 3 shows findings suspicious for volvulus: marked gastric dilatation, with a tight stenosis at the first duodenal portion, with mucosal hyperaemia and associated tortuous aspect of the corresponding meso and vascular peduncle (“Whirlpool sign”). No imaging features suggestive of intestinal ischemia were detected.

A fair amount of intra-abdominal effusion located in the pelvic cavity and between intestinal loops can be seen in Fig. 4.

Fig 5 shows gross pathology specimens of the bowel.

Background

Pneumatosis Cystoides Intestinalis (PCI) is defined as the presence of gas within the walls of the small bowel or colon. It can involve the mucosa, submucosa, subserosa or all three layers. PCI can affect all the gastrointestinal tract from the oesophagus to the rectum, as well as mesentery, the greater omentum and the hepatogastric ligament [1].

PCI is a rare condition (incidence 0.03%), typically developing in the fifth to eighth decade of life, with a 3:1 male-to-female ratio [2].

The pathogenesis is poorly understood: 15% of cases are idiopathic, with a chronic and benign aetiology, appearing with intramural cystic air pockets.

Theories proposed to explain the pathogenesis include mechanical, bacterial, and biochemical factors.

Among the wide spectrum of possible causes, enterocolitis, intestinal ischemia, volvulus, inflammatory bowel disease and previous endoscopic examination are the most common [3].

Clinical Perspective

Most cases of PCI are asymptomatic, never requiring clinical treatment. Common presenting symptoms include abdominal pain, obstruction, vomiting, diarrhoea, haematochezia. Complications occur in approximately 3% of cases [4] and can be intestinal or extra-intestinal [5], often resulting in small and/or large bowel obstruction, peritonitis, and perforation of the digestive tract [1].

Imaging Perspective

Abdominal radiographs may show a combination of bowel distention, intramural bowel gas, or free intrabdominal air [6].

CT is the gold standard for diagnosing PCI, showing a linear low-density, small bubbles and/or large cystic pattern gas in the bowel wall [7]. CT can also identify or suggest the possible cause of PCI, such as bowel wall thickening, bowel distention, arterial or venous occlusion [8]. Furthermore, CT can drive the therapeutic planning in patients suffering from bowel volvulus; the combination of Whirlpool sign and PCI, indeed, has proven to be strongly associated with fulminant bowel obstruction caused by the volvulus, requiring surgical intervention [9].

Outcome

Most PCI cases require conservative management. Exploratory laparotomy should be considered in case of peritoneal irritation or persistent bowel obstruction [2]. Surgical therapy is necessary in patients with severe complications, or to treat the underlying causes of PCI [10]. In our case, due to persistence and severity of symptoms, exploratory laparotomy was performed, and the presence of a starting pattern of necrosis made necessary a small bowel resection and anastomosis. 

Take-Home Message / Teaching Points

PCI is a rare, multifactorial, and little-understood condition.

CT scan has a pivotal role in the diagnosis of PCI and for the assessment of the intestinal wall, mesentery, and vessels involvement.

Monitoring of patients with PCI is recommended to identify early signs of complications [6].

Written informed patient consent for publication has been obtained.