The EC is characterized by dense infiltration of colonic wall with eosinophils, which can be a primary disease or secondary to parasitic infestations, vasculitis, and drugs such as carbamazepine, naproxen and tacrolimus (
1). The clinical picture depends on the layer that is most affected by the eosinophilic infiltration; if it is the mucosa then patients present malabsorption, diarrhea, and protein-losing enteropathy, in serosal involvement eosinophilic predominant ascites is the key clinical feature, ( 9) and in transmural affection, colonic wall thickening and intestinal obstruction occurs ( 10). Diagnosis of EC is done by measuring serum IgE levels, skin prick tests to identify specific allergens, endoscopy and biopsy, which typically shows sheets of eosinophils infiltrating the lamina propria extending into the sub-mucosa ( 1).
Pneumatosis intestinalis is a clinical condition defined as the extra-luminal presence of gas in the bowel wall, whether the small or large bowel. It is considered an ominous radiological finding rather than a disease per say (
The pathophysiology of PI is still controversial. Sources of extra luminal gas and mechanism of its entry are debatable, yet the main event is the breakdown of the mucosal barrier of the intestine accompanied by increased intraluminal pressure (
12). The insult of the intestinal mucosal barrier is usually related to variable causes, however in almost 15% of cases it can be an idiopathic phenomenon ( 4).
Pneumatosis Intestinalis can be secondary to mechanical factors such as endoscopy and carcinoma; inflammatory conditions such as necrotizing enterocolitis, Cohn’s disease and ulcerative colitis; autoimmune conditions such as scleroderma; infections such as
Clostridium difficile, HIV and cytomegalovirus; pulmonary causes such as chronic obstructive pulmonary disease and asthma; cytotoxic drugs and immunosuppression ( 2).
The diagnosis of PI depends mainly on abdominal CT scan, which is the most frequently used modality for diagnosis. Computerized-tomography scan is superior to abdominal radiography as it is more sensitive at detecting not only PI but also portal and porto-mesenteric venous gas, which may indicate the presence of serious causes of PI (
13). In CT imaging, PI usually has a linear pattern or a bubbly pattern of gas of low-density inside the bowel wall; intramural circular collections of gas can also exist ( 14). Sonography is also used to detect PI mainly in pediatric patients to avoid the risk of ionizing radiation that appears on sonography as linear or focal echogenic areas within the bowel wall ( 15). Magnetic Resonance Imaging can be sometimes used in the diagnosis of PI revealing a circumferential collection of air inside the bowel more clearly on gradient echo images ( 16).
Not every patient with PI requires an emergent surgery. Asymptomatic patients or those with mild symptoms are usually managed conservatively with no need of specific therapy, whereas patients with serious clinical presentation such as acute abdominal pain or bleeding are candidates for surgical intervention as their symptoms suggest intestinal mucosal injury.
While some authors (
2, 17) tend to consider PI a medical condition that should be treated conservatively, the patient in our report showed initial response to the medical treatment then the symptoms relapsed after resumption of oral intake with no response to medical therapy necessitating surgical intervention.
The patient initially presented abdominal colic that recurred regularly, especially after meals, associated with abdominal distention; this presentation was suggestive of colitis, yet the failure to respond to ordinary medications used in treatment of colitis and Irritable Bowel Syndrome (IBS) drew our attention to the possibility of an underlying specific pathology. The aforementioned investigations concluded the presence of EC.
In the patient of our report the right side of the colon was only affected, which agrees with the fact that eosinophilic colitis usually involves the proximal colon (
18). The infiltration of mucosa by eosinophils and the toxicity of eosinophil granule proteins to the tissues are responsible for the mucosal damage inflicted by eosinophilic colitis. This mucosal insult associated with increased intra-luminal pressure during colonic contractions initiated the sequence of PI in the patient of this report ( 19).
In a review of 25 cases of pneumatosis coli over 30 years, colitis was responsible for only 12% of cases and colectomy was only done in two patients (
20). This review reported a high recurrence rate that ranged between 50% - 78% similar to the patient in our report, who relapsed within a week, however the review stated that in 96% of cases the left side of the colon was affected, whereas the right side was affected in our patient.
The initial clinical and radiological improvement of the patient’s condition with conservative management can explain that the extent of mucosal damage induced by colitis was not remarkable; however, starting oral feeding at an early point caused exacerbation of the inflammatory process and recurrence of PI in a more aggressive pattern. As the medical treatment failed to achieve any improvement and as the abdominal signs became more prominent, surgical intervention was deemed the decision of choice. The reason we decided surgical intervention was that we decided prolonged medical treatment will not improve the condition as the abdominal signs became more prominent making us suspect an impending colonic perforation, that is why corticosteroids were not a part of the treatment plan, fearing it might induce colonic perforation as the presence of PI indicated a transmural affection of the colon rather than a simple mucosal injury.
We preferred to start with laparoscopic exploration of the abdomen to assess the extent of the problem and to proceed afterwards. The right side of the colon appeared dilated and pathologic, thus right hemicolectomy was performed with a covering ileostomy. The patient recovered from the surgery quickly and smoothly with no postoperative morbidity.
Eosinophilic colitis is a rare entity that has a good prognosis, however its association with pneumatosis coli could reflect a serious damage to the colonic mucosa, which can be correlated with the clinical findings. Although EC responds well to medical treatment, yet in certain cases where clinical signs are evident and pneumatosis coli is present, surgical intervention is the treatment of choice.