Further management of the patient
Throughout the first week of admission, the patient continued to have severe abdominal pain, fevers up to 39.4 oC and periods of delirium. Broad spectrum antibiotic therapy, i.e., IV Piperacillin/Tazobactam 4.5 g tds, was continued for the first 5 d. During this time the white cell count continued to rise and peaked at 20.4 × 109/L on day 4. Numerous blood cultures were also acquired during this period, but all samples demonstrated no growth.
A CT abdomen scan on day 5 showed extensive necrosis involving over 70% of the pancreas (Figure 1). This significant degree of necrosis combined with worsening inflammatory markers and continuing fevers with delirium prompted suspicion for infected necrotic pancreatitis. Consequently, the antibiotic regimen was changed from IV Piperacillin/Tazobactam 4.5 g tds to IV Meropenem 1 g tds and IV Fluconazole 400 mg daily, on day 5 of admission.
Figure 1 Axial contrast enhanced computed tomography scan showing extensive pancreatic necrosis with non-enhancement of the pancreas.
Enteral feeding was also commenced via nasogastric tube on day 5, but had to be discontinued on day 6 due to development of ileus. Enteral feeds were reinstated on day 11 and continued until discharge without further complication.
On day 10 of admission, the patient experienced one episode of small volume, painless bright red rectal bleeding. There was no palpable rectal mass on digital rectal examination. At this point in time, the rectal bleeding was presumed to be secondary to splenic flexure colitis or inflammatory changes in the mesocolon which were evident on CT abdomen scan (Figure 2).
Figure 2 Contrast enhanced computed tomography scan showing peripancreatic oedema and mesocolic inflammatory change.
A: Axial contrast enhanced computed tomography (CT) scan showing marked peripancreatic oedema extending into the lesser sac and to the splenic flexure (arrow showing splenic flexure of colon); B: Coronal contrast enhanced CT scan showing colon (arrow) with adjacent mesocolic inflammatory change secondary to pancreatitis.
On day 19, antibiotic therapy was ceased due to clinical and biochemical improvement. However, 4 d later the patient developed worsening abdominal pain and fevers. The patient was re-started on IV Meropenem and IV Fluconazole. A progress CT abdomen scan was suggestive of infected necrosis around the pancreatic body as evidenced by an interval increase in size and peripheral enhancement, despite the absence of gas (Figure 3).
Figure 3 Axial contrast enhanced computed tomography scan showing interval increase in size and peripheral enhancement of walled of pancreatic necrosis.
The antibiotic regime was continued for a further 17 d. During this time, the patient’s delirium resolved, he tolerated all enteral feeds, and he progressed to independent mobilisation. After maintaining a stable clinical status for 2 d post cessation of antibiotic therapy, the patient was discharged home on day 42. On discharge the patient’s serum CRP was 8.2. He was due to be followed up in clinic 4-6 wk following his discharge in the outpatient department. Our plan was to allow the pancreatic necrosis sufficient time to mature and wall off adequately, in order to facilitate drainage either endoscopically or surgically.
Unfortunately, 22 d following his discharge the patient represented to the Emergency Department with fever and rigors before he was seen in the outpatient department. He was hemodynamically stable, and his abdomen was non-tender, however the serum CRP had increased to 142 mg/L and white cell count was 14.6 × 109/L. Repeat CT abdomen revealed infected necrosis with the presence of gas locules within a large walled off cavity (Figure 4). Subsequently, the patient was admitted and commenced on IV Piperacillin/Tazobactam 4.5 g tds.
Figure 4 Walled of necrosis with locules of gas.
Oral contrast seen within the stomach (solid arrow).
The CT scan of his abdomen on readmission raised a new concern of a possible rectal malignancy with thickening of the rectal wall, which had not been appreciated on previous imaging. The patient underwent a flexible sigmoidoscopy on day 4 of his second admission, which revealed a fungating but non-obstructing 8 cm lesion in the rectum. Biopsy of the mass, magnetic resonance imaging of the rectum and staging CT confirmed a T3bN1aM0 adenocarcinoma of rectum (Figure 5). This finding led to an increased level of urgency to definitively manage the infected pancreatic necrosis to facilitate treatment of the rectal cancer.
Figure 5 T2 sagittal view of magnetic resonance imaging rectum.
Arrows showing rectal cancer.
The decision to drain the infected necrosis at this stage was driven primarily because he had presented with clinical features of infection and had developed new radiological features of infected necrosis with gas locules within the area of walled off necrosis. It was also an appropriate time for intervention given the collection was sufficiently mature and walled off making it a safe time to do so. The rectal cancer made it crucial for us to adequately drain his collection but the decision to intervene at this stage was driven primarily by his clinical features of infection and radiological features which supported this being an appropriate time to intervene.
By this stage (approximately 10 wk post-presentation), the patient had developed a sufficiently mature and walled off collection on imaging. This could have been approached endoscopically or surgically via a transgastric route. The authors preferred the endoscopic approach over surgery as this was less invasive and would have avoided the added insult of surgery and inherent morbidity associated with this. Surgery was reserved at this stage only if the endoscopic approach failed consistent with a step-up approach.
The patient was referred for endoscopic drainage and debridement of his walled off necrosis by the therapeutic gastroenterology team. On day 11 of his second admission he underwent endoscopic ultrasound guided Hot-AXIOS stent placement (Boston Scientific, Marlborough, MA, United States) and insertion (Figure 6). Further endoscopic debridement and removal of the nasocystic catheter was performed on day 18. At this procedure, pulsations of an arterial vessel were visible in the center of the necrotic cavity raising concern of possible arterial erosion and major hemorrhage. The AXIOS stent was therefore removed and two plastic, double-pigtail stents were positioned across the cyst-gastrostomy to ensure patency and ongoing drainage.
Figure 6 Sagittal computed tomography exam.
AXIOS cystogastrostomy stent Solid arrow showing stent. Hollow arrow delineating small residual cyst.
The patient’s recovery post-endoscopic necrosectomy was uncomplicated and he was discharged on day 28. Notably, he had received IV antibiotic therapy for the entire admission. The case was discussed at the oncology multidisciplinary meeting where it was initially decided to commence neoadjuvant radiotherapy without chemotherapy due to the presence of infected pancreatic necrosis.
The patient started neoadjuvant radiotherapy (50 Gy in 25 fractions) for his rectal cancer one week following his discharge. Given that he tolerated this without adverse effects and with effective ongoing drainage of his walled off pancreatic necrosis, he was then trialed on chemotherapy (Capecitabine) 10 d following his radiotherapy. He also tolerated the chemotherapy well.
Ten weeks post completion of chemoradiotherapy, the patient underwent a laparoscopic ultra-low Hartmann’s procedure and cholecystectomy. At the time of surgery, both the splenic flexure and mesocolon were fixed secondary to the inflammatory change from pancreatitis. These operative findings reinforced the decision to perform a non-restorative procedure, which had been discussed with the patient prior to surgery. Post-operative recovery was uneventful.
Histopathology revealed a T3 N0 low grade rectal adenocarcinoma with Grade 1 (moderate response) to neoadjuvant treatment. There was no lymphatic, vascular or perineural invasion and the margins of excision were clear. The patient attended regular general surgical outpatient appointments for review of his pancreatic necrosis as well as his rectal cancer. At 1 year follow up, there were no complications from the pancreatitis or evidence of rectal cancer recurrence.