Colocutaneous fistula following Clostridioides difficile infection managed as an ‘autocolostomy’: a novel approach to a recognised complication

Abstract

Colocutaneous fistula is a rare entity in colorectal disease. We present a case of colocutaneous fistula in a patient whose postoperative course following a laparoscopic anterior resection for sigmoid cancer was complicated by Clostridioides difficile colitis. During the follow-up period, it was found that his bowel contents were preferentially discharging through this fistula which had taken up the role of an ‘autocolostomy’. Given the physiological impact of an additional surgical procedure, a definitive repair of the fistula was deferred and instead the patient was taught to manage it in keeping with general principles of stoma care. Over the subsequent follow-up period, he has now developed a large parastomal hernia and is being considered for definitive repair.

Background

Clostridioides difficile infection (CDI) is a commonly encountered nosocomial infection that generally follows recent antibiotic use.¹ The spectrum of disease can range from self-limiting diarrhoeal illness to fulminant pseudomembranous colitis. Additional factors such as advanced age, immunosuppression, recent surgery and malnutrition are implicated in determining the severity of the disease.² This paper reports a case of colocutaneous fistula that was attributed to CDI following laparoscopic anterior resection for sigmoid cancer. Instead of definitive repair, the fistula was managed as an ostomy which helped the patient avoid undergoing another major abdominal procedure during the perioperative period.

Case presentation

A 75-year-old man was referred to the general surgery clinic with a 4-week history of altered bowel habits and per-rectal bleeding. He had a medical history of erosive oesophagitis, hypertension and dyslipidaemia. Abdominal and per-rectal examinations were unremarkable. He underwent an outpatient flexible sigmoidoscopy which revealed a circumferential polypoid mass in the rectosigmoid region. Biopsies were taken and cellular pathology was in keeping with a diagnosis of adenocarcinoma of the colon. A whole-body CT scan was performed and revealed circumferential thickening of the distal sigmoid colon. Additional findings included a large metastatic deposit in the right lobe of the liver and paraaortic lymphadenopathy (figure 1). These findings were in keeping with a radiological staging of a CT3N0M1a lesion. A positron emission tomography (PET) scan was performed which confirmed the hot spot in the liver to be a metastatic deposit (figure 2). Interestingly, the PET scan did not demonstrate the paraaortic lymphadenopathy seen on the initial CT. The patient was discussed at the local colorectal multidisciplinary team (MDT) meeting and regional hepatopancreaticobiliary (HPB) meeting and it was decided that initial resection of the primary tumour followed by resection of the liver metastatic deposit would be the best treatment approach. A colon-first approach was opted considering the tumour’s potential for causing bowel obstruction. The panel believed that the 3-month interval between resection of the colonic primary and the liver metastasectomy was unlikely to impact the resectability of the liver lesion. As an R0 resection was considered achievable in this patient, neoadjuvant chemotherapy was not offered. In addition, the HPB team did not feel that the patient would benefit from downsizing of the hepatic deposit using transarterial chemoembolisation and recommended a staged liver resection instead. He subsequently underwent elective laparoscopic anterior resection with intracorporeal anastomosis. Histopathology from the specimen confirmed a diagnosis of a Dukes C1 (pT3N2Mx) sigmoid adenocarcinoma. The lymph node harvest yielded a total of 6 out of 17 nodes.

Figure 1.

CT of the abdomen with intravenous contrast; coronal image of abdomen and pelvis showing the thickened sigmoid colonic tumour (white arrow) and liver metastasis (open black arrowhead).

Figure 2.

PET scan; coronal image demonstrating avid FDG uptake in a large liver deposit. FDG, fluorodeoxyglucose; PET, positron emission tomography.

Postoperatively, the patient developed persistently raised inflammatory markers and fever. He was empirically started on broad-spectrum antibiotics (amoxicillin, metronidazole and gentamicin), and a septic screen including a chest X-ray, urine and stool cultures was conducted. Despite the antimicrobial therapy, the patient remained persistently feverish and a septic screen was repeated on postoperative day 7. At this point, the patient’s chest X-ray findings were suggestive of a nosocomial pneumonia. The antibiotics were hence revised to piperacillin/tazobactam and gentamicin in keeping with local guidelines for hospital-acquired infections. A lack of clinical improvement, despite 14 days of broad-spectrum antibiotics, prompted a repeat septic screen and a microbiology review. At this point, the patient’s urine dipstick tested positive for pus cells and nitrites. A carbapenem was added to the patient’s treatment regime to account for a possible extended spectrum beta lactamase-producing organism. Soon after, the patient reported diarrhoea and abdominal distention. A stool sample was sent, and a CT scan was performed. The CT scan showed oedematous and thick-walled bowel loops in the proximal limb of the anastomosis, which was in keeping with localised colitis. In addition, a tiny locule of gas was seen projecting from the left side of the anastomosis which was reported as either being an isolated diverticulum or intraluminal air (figure 3). Stool samples tested positive for C. difficile and he was commenced on per-oral vancomycin and metronidazole in keeping with the local guidelines for the treatment of severe CDI.

Figure 3.

CT of the abdomen with intravenous contrast; coronal image showing oedematous colon (white arrows) from Clostridioides difficile infection.

On postoperative day 21, the patient developed feculent discharge from the left lower quadrant port site. A CT scan was repeated and showed interval development of a colocutaneous fistula approximately 15 cm proximal to the anastomotic site. This was managed conservatively and it appeared to have closed by the time of discharge. Three months and 13 days after the initial procedure, the patient underwent an elective right hemihepatectomy at a tertiary care centre (figure 4). His recovery was complicated by a postoperative collection at the surgical site that was managed conservatively, and resolution was confirmed with a repeat CT scan conducted at 3 months from the hepatectomy. Histology was reported as complete excision of 16 cm metastatic deposit from colorectal adenocarcinoma.

Figure 4.

CT of the abdomen with intravenous contrast; post-hepatectomy axial image showing surgical clips and a postoperative collection in the surgical site.

He was reviewed in outpatient clinic 3 and 6 months after discharge. During this time, the patient reported that he was passing most of his bowel contents exclusively through the fistula. A CT scan confirmed that the colon was discharging preferentially through the ‘stoma' and that the rectosigmoid stump also appeared to feed into this opening. He was presented with the options of a formal revision of the colostomy and conservative management, but he initially opted for the conservative management.

Outcome and follow-up

The patient has been followed up by both the HPB and colorectal teams. After weighing the potential toxicity of chemotherapeutic agents against their benefit and discussing these with the patient, adjuvant chemotherapy was not offered. Instead, he underwent routine surveillance which has included annual carcinoembryonic antigen levels and CT scans with no evidence of recurrence at 5 years. He was however found to have developed a large parastomal hernia (figure 5). The patient initially opted for using an abdominal corset in managing the parastomal hernia; however, this has become increasingly difficult due to the hernia’s progressive increase in size over the last 8 years. He has now expressed interest in definitive repair and has been discussed at a regional complex abdominal wall reconstruction (CAWR) MDT meeting. Recommendations from the MDT meeting will be relayed to him on further outpatient follow-up.

Figure 5.

Picture taken 9 years from the time of surgery showing the ‘autocolostomy’ (black arrow) with surrounding skin excoriation and the associated parastomal hernia (white arrow).

Discussion

C. difficile is a gram-positive, obligate anaerobic, spore-forming bacillus that is implicated in antibiotic-associated diarrhoea. The global incidence of healthcare facility associated-CDI is 2.24 per 1000 admissions per year.³ While pseudomembranous colitis was classically associated with clindamycin use, other commonly used antimicrobials such as penicillin have also been implicated in its development. Risk factors for developing CDI include broad-spectrum antibiotics; age and comorbidities; poor infection-control practices; gastrointestinal tract surgery and gastric acid-suppressing agents. Of specific significance, in this case, is the importance of antibiotic stewardship in the treatment of suspected postoperative sepsis. The patient had received broad-spectrum intravenous antibiotics for nearly 10 days before he was diagnosed to have CDI. He was treated empirically even though a septic screen including chest X-ray, urinalysis and blood cultures had failed to identify a source of infection.

Colocutaneous fistulas are generally encountered as a complication of diverticulitis or inflammatory bowel disease.⁴ Even within this context, they are a rare entity comprising 4% of all fistulas seen in diverticular disease.⁵ They almost exclusively arise as a result of instrumentation either in the form of operative intervention or radiological drainage. Less frequently, colocutaneous fistulas may arise spontaneously because of bowel neoplasm^{6 7} or infections including amoebiasis.⁸ With the exception of one CT scan that demonstrated a locule of gas that may have been an isolated diverticulum, our patient did not have evidence of diverticular disease on imaging or sigmoidoscopy. He did, however, have radiological evidence of localised colitis of the descending colon prior to developing a fistula. These changes were attributed to his CDI which was diagnosed soon after. Fulminant CDI is associated with bowel perforation.^{9 10} It may also cause localised colitis sparing other parts of the bowel.¹¹ In our patient, we postulated that a localised perforation secondary to CDI led to the formation of a fistulous tract between the colon and the abdominal wall. The alternative theory is that the ongoing colitis led to perforation of the isolated diverticulum noted on the patient’s initial postoperative scan and subsequently caused the formation of a colocutaneous fistula. Another consideration is that a subclinical anastomic leak may have been the precipitant for this patient’s clinical course. Additional contributing factors in this patient were his recent history of bowel resection surgery, advanced age and poor nutritional status which was evidenced by albumin levels of 16 g/L on his postoperative work-up.

The management of colonic fistulas is determined by symptomatology and anatomical considerations. The initial course of action is usually conservative with an emphasis on stabilisation. 'SNAP' is an acronym that is commonly used to describe parameters for conservative management of enterocutaneous fistulas. Its components are management of sepsis, nutrition, the definition of anatomy and proposing a procedure to address the fistula.¹² The optimal timing for surgical intervention in these cases has not been clearly defined; however, this is generally undertaken after 12 weeks of conservative management. The reasoning behind this is to allow for spontaneous closure. Ninety-one per cent of enterocutaneous fistulas will close within the first 4 weeks and, of the remainder, an additional 9% close by 12 weeks.^{13 14} This is, however, in contrast to colocutaneous fistulas which require surgical intervention more frequently. One series found that an estimated 46% of patients with colocutaneous fistulas required operative intervention to achieve closure.¹⁵

In our patient, a trial of conservative therapy was opted initially and by the time of discharge, the fistula appeared to have closed based on clinical and radiological evidence. However, by the time of outpatient review, post-hepatectomy, it was found that his bowel contents were discharging exclusively from the fistula. It was evident that the fistula had now taken up the role of a stoma, that is, an ‘autocolostomy’. At the time, definitive repair, including refashioning a new colostomy, was discussed with the patient; however, he chose to defer undergoing yet another major surgical procedure. He was consequently referred to the hospital’s stoma care nurses to guide him regarding caring for his ostomy. Except for the development of a paracolostomy hernia after many years of follow-up, the patient reported no issues with the stoma on subsequent follow-up. After 13 years from the original operation, he has now expressed an interest in repair of the large paracolostomy and incisional hernia. After discussion in the regional CAWR MDT, the following surgical options have been suggested: (1) single-stage approach with biological/prosthetic mesh repair of both large paracolostomy and incisional hernia, reversal of paracolostomy and primary colorectal anastomosis with or without covering ileostomy; (2) complex abdominal wall reconstruction which entails the use of biological/prosthetic mesh repair of the large paracolostomy and incisional hernia, and formalisation of the colostomy; and (3) deferring surgery altogether. These options are yet to be discussed with the patient and the final surgical approach will be guided by his metabolic and physiological age.

Learning points.

• Judicious use of antimicrobials is imperative to avoid the development of Clostridioides difficile infection (CDI).

• In addition to more commonly seen complications, CDI may be a rare cause of colocutaneous fistula.

• Spontaneous closure of colocutaneous fistula is very uncommon.

• Surgical intervention may not always be necessary in cases of persistent colocutaneous fistula.

• The patient’s metabolic and physiological age should be considered before undertaking complex abdominal wall reconstruction.