Clinical History
Diffused abdominal pain, nausea, vomiting and leukocytosis (18.700 WBC/ml) developed in a 55-year-old man, already treated with antibiotics for a suppurative swelling of his right scrotum. At physical examination there were no signs of peritonitis and laboratory revealed moderately elevated acute phase reactants (46.7 mg/L CRP). To exclude abdominal abscesses CT examination was required.
Imaging Findings
Abdominal CT examinaton revealed a 12 cm segment thickening of the jejunal loop with marked enhancement after CM administration, associated with an enormous upstream dilation of the small bowel loops (Fig. 1). Multiple associated lymphadenopathies, along aorta and inferior caval vein, were also detected (Fig. 1). Based on CT findings the differential diagnosis included Crohn disease, lymphoma, small bowel tumour, infective ileitis and ischaemic ileitis.
Further investigation with a small bowel examination revealed a 10 cm severe stenosis localized in the third portion of the jejunum (Fig. 2). The presence of mucosal folds within the surface of the stenosis were more consistent with submucosal origin rather than from the mucosal layer ruling out the hypothesis of a small bowel tumour.
The patient underwent laparotomic surgery due to mechanic occlusion of the small bowel. At pathological analysis, the specimen revealed pseudomembranous ileitis (Fig. 3). Enterococcus faecalis was the only pathogen detected.
Discussion
Pseudomembranous enterocolitis (PMEC) primarily occurs in the large bowel, but rarely also affects the small bowel, as in our case. Since the 1970s Cl. difficile has been recognized as the most common cause, but other organisms such as St. aureus and Escherichia coli and other pathogens could be related to PMEC [1]. Our microbiological examination isolated only Ent. faecalis, an unusual cause of PMEC.
The pseudomembranes are yellow-white, elevated plaques on the intestinal mucosa which can be observed at both pathological analysis and endoscopy [2]. PMEC usually occurs as a complication of antibiotic treatment, but is also associated with abdominal surgery, colonic obstruction, uraemia or hypoperfusion of bowel [2]. PMEC also occurs with increased frequency in patients with severe debilitating diseases. Symptoms are watery diarrhoea (99%), fever (29%), abdominal pain or cramping (33%) and leukocytosis (61%). PMEC is diagnosed by assessing the patient with clinical evaluation, stool assays for enteric pathogens and visualization of the colonic mucosa. The diagnosis includes detection of the bacteria in the stool. Colonoscopy or sigmoidoscopy allow visualization of pseudomembranes [3]. The differential diagnosis must exclude other causes which may mimic PMEC such as medication-inducted GI disease or other chronic conditions (Crohn’s disease, ischaemic colitis, collagenous colitis) [3]. Usually imaging is not the method of choice in the diagnosis, however, plain radiography, barium enema studies and CT may contribute to the diagnosis [2]. Plain-film findings depend on the severity and extent of the disease. In severe cases, it can demonstrate “thumb printing”, mucosal thickening, toxic megacolon and even colonic perforation; unfortunately it's not very sensitive [2]. Barium enema, in mild cases, shows small nodular fillings, whereas with more extensive involvement, mural thickening and wide haustral folds due to intramural oedema may also be seen [2]. Common CT findings include wall thickening, low-attenuation mural thickening corresponding to mucosal and submucosal oedema, the “accordation sign” (oral contrast trapped between markedly thickened haustral folds), the “target sign” or “double halo sign” (inflammation of the mucosa and the bowel wall which may enhance markedly following intravenous bolus administration, still not specific for PMEC). There may also be pericolonic stranding. The two most commonly used antibiotics to treat Cl. difficile disease are metronidazole and vancomycin usually administered for 10 days.
Although unusual, small bowel localization of PMEC should be suspected in patients with long course antibiotics treatment or without common causes of bowel thickening.
Differential Diagnosis List
Pseudomembranous ileitis
Lymphoma
Crohn disease
Small bowel tumour
