When encountering a patient presenting with a bout of acute pancreatitis, clinicians should not only provide aggressive intravenous fluid resuscitation and symptom control but also perform a thorough work-up to determine the etiology of the pancreatitis, use one of several scoring systems to try to predict the severity of disease, and counsel patients on warning signs of possible future complications of pancreatitis. The rationale for aggressive intravenous fluids and the use of scoring systems have been reviewed in other chapters, so my focus here will be to briefly review his work-up in regard to the etiology of his pancreatitis and concentrate mostly on the treatment of walled-off pancreatic necrosis which later developed as a complication of his initial presentation.

Determining the etiology of pancreatitis can be essential to treat the acute episode and prevent future bouts. In this case, it was determined that alcohol did not play a significant role in his illness as he reported drinking alcohol rarely which was corroborated by his wife. He also had a history of tobacco use but had quit smoking after developing coronary artery disease several years earlier. Ultrasound and CT imaging of his gallbladder and biliary system did not reveal any cholelithiasis or choledocholithiasis, and labs revealed normal calcium and triglyceride levels. Although he did present with an unwitnessed syncopal event, it was not felt that he sustained any trauma to his abdomen as a result of his fall, and it was likely the severe pain of his pancreatitis and dehydration from diarrhea that precipitated syncope. Drug-induced pancreatitis was entertained secondary to his losartan or hydrochlorothiazide use, but he had been stable on that drug regimen for several years.

His first admission was complicated by severe acute kidney injury requiring brief renal replacement therapy before complete renal function recovery likely due to the severity of his dehydration secondary to diarrhea on presentation. The conclusion of his first admission was that the etiology of his pancreatitis was indeterminate and thought possibly to be drug induced, microlithiasis related, or possibly idiopathic. His previous home antihypertensive regimen was discontinued, and although he improved greatly, he continued to have progressive pain after eating and diarrhea after hospital discharge.

It was not until his second admission, 4.5 weeks after his initial presentation for worsening abdominal pain, when the true etiology of his pancreatitis was determined after an infectious work-up took place due to persistent fevers, elevated white count, and ongoing diarrhea that revealed positive stool and blood cultures for Salmonella. Infection is an uncommon cause of pancreatitis in adults, and it is not recommended to routinely screen for infection as an etiology for pancreatitis in the absence of infectious symptoms. Of interest, his wife had also mild diarrheal illness related to Salmonella diagnosed around the time of his initial presentation.

When encountered with symptomatic WOPN, there are several different approaches that can be considered for treatment. Those patients with no or minimal symptoms could be managed expectantly with watchful waiting and serial imaging. Studies of this approach performed in the 1990s suggest that about 60% of patients followed in this manner have complete resolution of the pancreatic collection over time, whereas the remaining patients developed a complication or required surgical management [1, 2].

The traditional treatment for WOPN would be open or laparoscopic surgical necrosectomy. This technique may still be practiced routinely in areas where radiologic guided or endoscopic drainage procedures are not available, but in general is not favored due to its invasiveness and evidence of worse patient outcomes that have been documented in several studies. Open surgical drainage can be accomplished by surgical resection of the area in question or surgically created cystenterostomies or cystogastrostomies for drainage. Laparoscopic surgical necrosectomy would possibly involve a distal pancreatectomy if the collection was in the body or tail or the creation of a cystogastrostomy, cystenterostomy, or drainage via the creation of a Roux limb of the jejunum. Contemporary studies comparing surgical necrosectomies and less invasive approaches continue to suggest higher morbidity and mortality with surgical techniques with one retrospective study showing higher rates of sepsis and persistent multiorgan dysfunction (73.3 vs. 44.7%), higher mortality (33.3 vs. 10.5%), and higher rates of diabetes (33.3 vs. 4.7%) when comparing surgical to less invasive techniques [3]. Surgical approaches may still be required if the collection is not amenable or is refractory to an endoscopic or radiologic approach.

Percutaneous catheter drainage remains another option for the treatment of WOPN that can be as effective as a surgical approach. This technique uses radiology guidance to establish percutaneous access into the pancreatic collection to allow the placement of a drainage catheter which can then be upsized over time to allow for the removal of necrotic debris. Advantages of this technique include its minimally invasive nature and lower associated mortality rate, but disadvantages include the possibility of creating a pancreaticocutaneous fistula and infection of the drain track. Studies of percutaneous drainage for WOPN have demonstrated it to be a feasible stand-alone treatment in a little less than 50% of patients [4, 5] with one study of 34 patients showing a 12% mortality rate in four out of eight patients that failed to show clinical improvement after a percutaneous approach who eventually required surgical drainage [4]. In one series of 52 patients, it took a mean of 42 days to drain the WOPN by a percutaneous approach [6]. The current role of percutaneous drainage is in the management of retroperitoneal WOPN that may not be amenable to endoscopic therapy or to stabilize septic patients prior to a surgical or endoscopic approach.