Fulminant Necrotizing Enteritis after Revisional Roux-en-Y Gastric Bypass: A Rare Case and Review of the Literature

Case Presentation

A 38-year-old female with a body mass index (BMI) of 65.3 kg/m² presented to the bariatric clinic for revision weight loss surgery after a failed laparoscopic gastric band. Past medical history included hypertension, myocardial infarction, type 2 diabetes mellitus, and obstructive sleep apnea. Past surgical history included four cesarean deliveries and a laparoscopic gastric band that was inserted six years prior at an outside facility. After pre-operative evaluation by the cardiologist and endocrinologist, the patient was found eligible for robot-assisted gastric band removal and conversion to RYGB per the guidelines of the National Institutes of Health (BMI >40 kg/m²). Diagnostic laparoscopy and extensive laparoscopic lysis of adhesions were performed. The gastric band appeared embedded into the second segment of the liver surface. Next, the da Vinci^® Si robot system (Intuitive Surgical, Sunnyvale, CA) was docked from the patient's head end. Gastric band removal was technically challenging but was carried out uneventfully. We then proceeded with the creation of alimentary and pancreato-biliary limb (150 cm Roux limb) according to the standardized technique. Intra-operative esophagogastroduodenoscopy confirmed patency and vascularization of the gastrojejunostomy (GJ) without evidence of a leak. The patient tolerated the procedure well and was transferred to the surgical floor.

Bariatric clear liquid diet was initiated on post-operative day two after a negative upper gastrointestinal (GI) study with gastrografin. On post-operative day three, the patient became febrile and complained of abdominal pain. Computed tomography (CT) scan of the abdomen revealed subcutaneous fluid collection over the para-umbilical port site and mild diffuse small bowel dilatation suggestive of ileus. Skin staples from the involved surgical site were removed and the fluid collection was drained. Antibiotics (piperacillin-tazobactam and vancomycin) were initiated because of elevated white cell count, fever, and purulent discharge. Over the next three days, the patient improved symptomatically, tolerated bariatric clear liquid diet, and the white cell count decreased. On post-operative day seven, the antibiotics were withdrawn as the incision culture returned negative and the patient was to be discharged home. While awaiting transport, the patient developed an episode of emesis and desaturation. The repeat CT scan of the abdomen and pelvis revealed extensive small bowel pneumatosis (Fig. 1A) suspicious of ischemia. Exploratory laparotomy revealed diffusely edematous and distended small bowel without any visible necrosis of the sero-muscular layers. Intra-operative examination of the mesenteric flow did not reveal proximal or distal occlusion of the mesenteric flow. Bowel decompression was performed with the assistance of tube colostomy in the ascending colon draining large amount of fluid contents. Samples of intra-peritoneal fluid and drained intestinal contents were sent for culture. The abdominal incision was closed temporarily with negative-pressure assist device (wound vacuum-assisted closure [VAC]) as we had planned for a second exploratory surgery within 48 h. Empiric treatment with ceftriaxone and metronidazole was initiated while awaiting the results of culture. Glycemia was controlled with a sliding-scale insulin regimen and ranged between 85–194 mg/dL.

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FIG. 1.

(A) Computed tomography scan of the abdomen displaying the dilated bowel loops and pneumatosis. (B) Intra-operative image showing the small patch covered by fibrinous tissue on the isolated loop of ileum.

The re-exploration revealed persistent and extensive distension of the entire small bowel. An isolated loop of ileum with a 0.5 cm patch of fibrinous tissue (Fig. 1B) was found overlying a thin wall over its anti-mesenteric border. This area was reinforced with interrupted 4-0 polydioxanone (PDS) Lembert sutures. The wound VAC was re-applied and patient was left intubated. Pressor support with norepinephrine was initiated as the patient was acidotic and hypotensive. On post-operative day one after re-exploration, the antibiotics were changed to vancomycin and piperacillin-tazobactam because of positive stool culture showing Pseudomonas aeruginosa infection. Shortly thereafter, the patient experienced bradycardia and asystole for which chest compression was started per advanced cardiac life support protocol. After multiple failed cycles of cardiopulmonary resuscitation, the patient died. An autopsy was performed and showed intact GJ and intestinal anastomoses with no evidence of leak or perforation. Small intestine showed multiple plaques of fibrinous tissue with a foul-smelling red-brown fluid. Microscopic examination of the small and large bowels revealed areas of full-thickness inflammation with necrosis of the mucosa, submucosa, muscularis, and serosa. Multiple sections also showed partial thickness inflammation with a combination of autolysis and necrosis. In view of positive Pseudomonas stool culture in addition to the gross and microscopic autopsy findings, the diagnosis was confirmed as necrotizing Pseudomonas enteritis.

Discussion

Pseudomonas aeruginosa is the most important opportunistic organism that is found on the skin, nose, throat, and in stools. It is known to cause infection in immunocompromised patients and in conditions such as neutropenia and hypogammaglobulinemia [5]. Pseudomonas enteritis leading to sepsis known as Shanghai fever, such as the case described above, is rare and has been reported to date only in healthy pediatric patients of Asian origin [3,5]. Community-acquired infection was believed to be the etiology in the majority of cases. On the contrary, in the adult population, non-intestinal pseudomonal infection and uncomplicated intestinal colonization are the common source of Pseudomonas aeruginosa infection currently described in the literature [2] . Antibiotic administration, in particular amoxicillin and clavulanic acid, has been identified as a strong pre-disposing factor in the affected adult population [6]. Furthermore, surgical and metabolic stress have been demonstrated as a risk factor for Pseudomonas enteritis sepsis in several animal models [7]. In our case, the start of piperacillin-tazobactam and vancomycin on post-operative day two to treat a surgical site infection could have played a role in the development of intestinal Pseudomonas aeruginosa colonization. The surgical stress with co-existent diabetes mellitus may have also contributed to the onset of necrotizing enteritis.

Clinical features of Shanghai fever include fever, diarrhea, vomiting, dyspnea, abdominal distension, and diffuse ulcerative lesions of the entire GI tract [1,3]. In the fulminant form, it can be complicated with widespread necrotizing bowel lesions that can ultimately result in bowel perforation requiring small bowel resection [4]. Intra-operative findings usually reveal widespread patchy necrosis with fibrin coating of the small intestine or colon [3,4]. Ecthyma gangrenosum, a well-recognized cutaneous manifestation of Pseudomonas aeruginosa infection with or without sepsis [8] was also another presentation in more than 50% of the reported cases. This manifestation helped identify the cause of infection to an extent. In the absence of ecthyma gangrenosum, biopsy of the ulcerative lesions and stool cultures can assist with the diagnosis. Imaging findings are usually non-specific and are suggestive of bowel dilatation and/or small bowel obstruction or ischemia [1,4]. In our case, the patient presented initially with an episode of emesis, desaturation, fever, and gradual abdominal distension. Computed tomography scan of the abdomen revealed small bowel pneumatosis with marked dilated bowel loops that was suggestive of ischemia. The first laparotomy failed to show evidence of acute ischemia and revealed only an extensively dilated and aperistaltic small bowel. During re-exploration, the only abnormal finding was a minimal fibrinous change of a loop of small bowel without any obvious necrosis that in retrospect could have pointed out a Pseudomonas aeruginosa enteritis as reported in the literature (Fig. 1B). The absence of ecthyma gangrenosum, absence of concomitant neutropenia, or prior history of immune deficiency, a negative prognostic factor, contributed further to the challenges faced during diagnosis [9]. The delay in diagnosis experienced in our case is in agreement with the pediatric literature in which this factor contributed to a mortality rate as high as 89% [3,5]. Despite these challenges, surgical exploration and empiric antibiotic treatment were promptly implemented in our patient but did not affect the overall prognosis because of the fulminant course of this rare infectious condition.

An argument may arise that the revision RYGB could have been performed in two stages with removal of the band first and gastric bypass a few weeks later to decrease the risks of peri-operative morbidity and mortality. However, there is no level 1 evidence and/or universal consensus among the bariatric surgery community supporting the concept that the two-stage approach after failed laparoscopic gastric band is safe [10]. Furthermore, a two-stage approach implies two procedures under general anesthesia in a patient with multiple comorbidities and an overall higher risk of anesthesia-related complications.

Conclusion

This report describes the first case of fulminant necrotizing Pseudomonas aeruginosa enteritis in an adult patient after robot-assisted revision RYGB. The findings of the currently available literature highlighting the various clinical presentations and the optimal medical and surgical management of this rare condition are also summarized.