There is no characteristic clinical presentation of pneumatosis. Patients may be asymptomatic or complain of pain and abdominal distension, diarrhea and rectal blood loss with a mortality rate that may reach 75%[23
]. Apart from the cases associated with chronic intestinal pseudo-obstruction[20,24,25
], the majority of cases reported in the literature present with diarrhea; in the present manuscript we described two cases of PCI that presented with stipsis. The first was diagnosed after a colonoscopy that put the suspect of PCI, while the second required a CT scan because of the atypical presentation and the misleading anamnesis. In fact, the history of celiac disease lead the clinicians to hypothesize a complication of the pre-existent disease more than the onset of a new pathology. It is difficult to say whether the motility defects are a cause or a result of the pathologic condition and we are not aware of any longitudinal study evaluating such a question. However, on a purely hypothetical basis, it seems more reasonable to think that motility defects are secondary to PCI or to underlying pathological process that may have lead to PCI (i.e., ischemia, diverticular disease, etc
Colonoscopy is frequently requested to exclude colonic lesions. The endoscopic appearance of PCI is typically dual: multiple white small cysts coupled to a sub-atrophic mucosa or larger cysts (up to 3 cm) with a reddened overlying mucosa[26
]. The cysts usually collapse when biopsied. Nowadays, given the increasing number of colonoscopies performed because of the colon cancer screening programs, the endoscopists should be aware of the endoscopic appearance of this rare pathology. In fact, some patients may be asymptomatic and in such cases the clinical suspect may rely on the endoscopist performing the procedure. In our case 1, the endoscopist cautiously biopsied the cyst because of his unusual appearance that was not suggestive of a typical polyp. This allowed a confirmation of the suspect and avoided an unnecessary snare polypectomy with the related costs and complications.
A simple X-ray of the digestive tract may show a change in the characteristics of the intestinal wall in two-thirds of these patients leading to further investigations. However, one third of the patients do not have a suggestive X-ray and require a CT scan/magnetic resonance imaging, showing a thickened bowel wall containing gas to confirm the diagnosis[27
]. Suggestive images on plain radiography comprise different pattern of radiolucency: linear, small bubbles or collection of larger cysts[27
]. CT is more sensitive than plain radiography in distinguishing PCI from intraluminal air or submucosal fat. In fact, CT more easily visualizes the presence of air in the bowel wall. Furthermore, CT allows the detection of additional findings that may suggest an underlying, potentially worrisome cause of PCI, i.e., bowel wall thickening, altered contrast mucosal enhancement, dilated bowel, soft tissue stranding, ascites, and the presence of portal air[28
The intestinal pneumatosis may experience various complications, in particular, Goel et al[29
] described the complications of pneumatosis of the small intestine which may be intestinal or extra-intestinal. Intestinal complications are obstruction caused by the cysts (i.e., fecal impaction) and perforation from stercoral ulceration. The extra-intestinal complications are adhesions or compression of adjacent structures by large masses of cysts.
For the resolution of these complications surgical treatment is often required because sometimes we have a picture of pneumoperitoneum due to rupture of cysts.
To determine the need for surgical therapy Knechtle et al[23
] found a correlation between the clinical presentation, the need for surgery and the final outcome. It is necessary to evaluate six physical parameters, like pain, diarrhea, fever, tenderness, rectal blood loss and hypotension, and their severity coupled to clinical laboratory tests including white blood cell count, aspartate aminotransferases, alanine aminotransferases, alkaline phosphatase, pH, bicarbonate, lactic acid and amylase.
Surgical therapy is still a second-line therapy, chosen especially for complications, the first approach is oxygen therapy. It is also our opinion that the clinical decisions should not rely only on the radiologic picture of pneumoperitoneum, but should be coupled to the clinical symptoms (i.e., the positivity of the Blumberg sign). In fact, when the mucosa is intact surgery may be avoidable as in our case 2.
The rationale of oxygen treatment is based on increasing partial pressure of oxygen in blood and thus increasing the pressure gradient of the gas in the cysts. Cysts release gases contained within them and refills with oxygen which is then metabolized leading to resolution[26
Oxygen therapy can be made through humidified oxygen administered by Venturi mask (6 L/min) or nasal cannula (4 L/min). However, treatment with oxygen at high doses can be toxic. The patient may experience a narcotic effect and therefore lung function should be monitored closely (during therapy) by measuring the vital capacity, daily blood gas estimations and chest radiography. A decrease in lung vital capacity can be a early parameter of oxygen toxicity[30
To reduce the duration of oxygen administration hyperbaric oxygen can be used at a pressure of 2.5 atmosphere for up to 2 h a day [31
]. To decrease the recurrence rate oxygen therapy should be continued until two days after the disappearance of cysts[32
In conclusion, our cases confirm that the clinical presentation of PCI may be very heterogeneous and suggest that a new onset of stipsis might be the presenting symptom. Furthermore, it should be taken into account that the patients may also be totally asymptomatic. The clinicians and the endoscopist should be aware of the possible presentations of PCI in order to correctly manage the patients affected with this disease and avoid unnecessary surgeries. It is possible that with the increasing number of colonoscopies performed for colon cancer screening PCI is casually encountered and/or provoked, therefore the possible endoscopic appearances of this disease should be known.