Acute Pancreatitis Guidelines

In 2013, the American College of Gastroenterology (ACG) issued guidelines for the management of acute pancreatitis (AP), including the following ^[40] :

• Because AP can usually be diagnosed based on clinical symptoms and laboratory testing, contrast-enhanced computed tomography (CT) scanning and/or magnetic resonance imaging (MRI) of the pancreas should be performed only in the absence of clinical improvement or if the diagnosis is unclear

• Assessment of the patient’s hemodynamic status should occur immediately upon presentation, with resuscitative measures initiated as necessary

• Patients with systemic inflammatory response syndrome (SIRS) and/or organ failure should, if possible, be admitted to an intensive care unit (ICU) or an intermediary care setting

• All patients should receive aggressive hydration, unless this is precluded by cardiovascular and/or renal comorbidities; aggressive intravenous (IV) hydration is most effective within the first 12-24 hours, with possibly little benefit derived from its administration after this point

• Within 24 hours of admission, patients with concurrent acute cholangitis should undergo endoscopic retrograde cholangiopancreatography (ERCP); in high-risk patients, the risk of severe post-ERCP pancreatitis should be reduced through the use of postprocedure rectal nonsteroidal anti-inflammatory drug (NSAID) suppositories and/or pancreatic duct stents

• The guidelines recommend against routinely using prophylactic antibiotics in cases of severe acute pancreatitis and/or sterile necrosis; however, intervention in patients with infected necrosis may be delayed through the use of antibiotics that do not penetrate the necrotic tissue

• In mild cases of acute pancreatitis with no nausea and vomiting, oral feeding can be initiated immediately; enteral nutrition should be used in severe cases to prevent infectious complications, and parenteral nutrition should be avoided

• Regardless of the lesion's size, location, and/or extension, intervention is not necessary for asymptomatic pancreatic and/or extrapancreatic necrosis and/or pseudocysts

• Surgical, radiologic, and/or endoscopic drainage in stable patients with infected necrosis should be postponed (for 4 weeks if possible) to permit a wall to develop around the necrosis

2018 AGA guidelines (initial AP management)

In March 2018, the American Gastroenterological Association (AGA) released guidelines on the initial management of acute pancreatitis (AP). ^[41] These are outlined below.

The diagnosis of AP requires at least two of the following features: characteristic abdominal pain; biochemical evidence of pancreatitis (ie, amylase or lipase elevated >3 times the upper limit of normal); and/or radiographic evidence of pancreatitis on cross-sectional imaging.

Presentations of AP occur along a clinical spectrum and can be categorized as mild, moderately severe, or severe, based on the recent revised Atlanta classification.

Most cases of AP (around 80%) are mild, with only interstitial changes of the pancreas without local or systemic complications.

Moderately severe pancreatitis is characterized by transient local or systemic complications or transient organ failure (< 48 hours), and severe AP is associated with persistent organ failure.

Necrotizing pancreatitis is characterized by the presence of pancreatic and/or peripancreatic necrosis, and is typically seen in patients with moderately severe or severe AP.

There are two overlapping phases of AP, early and late. The early phase of AP takes place in the first 2 weeks after disease onset, and the late phase can last weeks to months thereafter.

In patients with AP, the AGA suggests against the use of hydroxymethyl starch (HES) fluids.

In patients with predicted severe AP and necrotizing AP, the AGA suggests against the use of prophylactic antibiotics.

In patients with acute biliary pancreatitis and no cholangitis, the AGA suggests against the routine use of urgent endoscopic retrograde cholangiopancreatography (ERCP).

In patients with AP, the AGA recommends early (within 24 hours) oral feeding as tolerated, rather than keeping the patient nil per os (NPO).

In patients with AP and inability to feed orally, the AGA recommends enteral rather than parenteral nutrition.

In patients with predicted severe or necrotizing pancreatitis requiring enteral tube feeding, the AGA suggests either nasogastric or nasojejunal route.

In patients with acute biliary pancreatitis, the AGA recommends cholecystectomy during the initial admission rather than after discharge.

In patients with acute alcoholic pancreatitis, the AGA recommends brief alcohol intervention during admission.

2015 AGA guidelines (pancreatic cysts)

As of 2015, the AGA recommends the following in the diagnosis and management of asymptomatic neoplastic pancreatic cysts ^[42] :

• For asymptomatic mucinous cysts, a 2-year interval is recommended for a cyst of any size undergoing surveillance, with surveillance being stopped after 5 years if there is no change.

• Perform surgery only if there is more than one concerning feature on MRI confirmed on endoscopic ultrasonography (EUS) and only in centers with high volumes of pancreatic surgery, and there should be no surveillance after surgery if there is no invasive cancer or dysplasia.

• The risk of malignant transformation of pancreatic cysts is approximately 0.24% per year, and the risk of cancer in cysts without a significant change over a 5-year period is likely to be lower.

• The small risk of malignant progression in stable cysts is likely outweighed by the costs of surveillance and the risks of surgery.

• Positive cytology on EUS-guided fine-needle aspiration (FNA) has the highest specificity for diagnosing malignancy; if there is a combination of high-risk features on imaging, that is likely to increase the risk of malignancy even further. Similarly, if a cyst has both a solid component and a dilated pancreatic duct (confirmed on both EUS and MRI), the specificity for malignancy is likely to be high even in the absence of positive cytology.

• There is lower immediate postoperative mortality, as well as long-term mortality, for patients who undergo surgery in high-volume pancreatic centers.

• It seems sensible to offer screening even after the cyst has been resected, provided the patients have not undergone total pancreatectomy. Surveillance should continue as long as the patient remains a good candidate for surgery. MRI every 2 years may be a reasonable approach for these patients. The clinician may elect to offer more frequent surveillance in the case of invasive cancer resection, particularly if there is concern that the lesion has not been fully resected.

In June 2019, the World Society of Emergency Surgery (WSES) released updated guidelines for the management of severe acute pancreatitis. ^[43] Their strong recommendations are summarized below.

Severity grading

Grade 1C recommendations

Severe acute pancreatitis is associated with persistent organ failure (cardiovascular, respiratory, and/or renal), and high mortality. Both new classification systems, Revised Atlanta Classification and Determinant-based Classification of Acute Pancreatitis Severity, are similar in establishing the diagnosis and severity of acute pancreatitis.

Patients who have persistent organ failure with infected necrosis have the highest risk of death.

Patients with organ failures should be admitted to an intensive care unit (ICU) whenever possible.

Diagnostic laboratory parameters

The cut-off value of serum amylase and lipase is normally defined to be three times the upper limit.

A hematocrit level above 44% represents an independent risk factor of pancreatic necrosis (grade 1B recommendation).

Imaging

Grade 1C recommendations

On admission, perform ultrasonography (US) to determine the etiology of acute pancreatitis (biliary).

When doubt exists, computed tomography (CT) scanning provides good evidence of the presence or absence of pancreatitis.

Assess all patients with severe acute pancreatitis with contrast-enhanced CT (CE-CT) scanning or magnetic resonance imaging (MRI). Optimal timing for the first CE-CT assessment is 72-96 hours after symptomatic onset.

Consider MR cholangiopancreatography (MRCP) or endoscopic ultrasonography to screen for occult common bile duct stones in patients with unknown etiology.

Follow-up imaging (all grade 1C recommendations)

In severe acute pancreatitis (CT scan severity index ≥ 3), a follow-up CE-CT scan is indicated 7-10 days from the initial CT scan.

Additional CE-CT scans are recommended only if the patient's clinical status deteriorates or fails to show continued improvement, or when invasive intervention is considered.

Surgical intervention

The following are indications for surgical intervention (all grade IC recommendations):

• As a continuum in a step-up approach after percutaneous/endoscopic procedure with the same indications

• Abdominal compartment syndrome

• Acute ongoing bleeding when an endovascular approach is unsuccessful

• Bowel ischemia or acute necrotizing cholecystitis during acute pancreatitis

• Bowel fistula extending into a peripancreatic collection

The following are indications for emergent endoscopic retrograde cholangiopancreatography (ERCP):

• Routine ERCP with acute gallstone pancreatitis is not indicated (grade 1A recommendation).

• ERCP in patients with acute gallstone pancreatitis and cholangitis is indicated (grade 1B recommendation).

Surgical strategies include the following:

• Infected pancreatic necrosis: Percutaneous drainage as the first-line treatment (step-up approach) delays the surgical treatment to a more favorable time or results in complete resolution of the infection in 25-60% of patients; it is recommended as the first line of treatment (grade 1A recommendation).

• Minimally invasive surgical strategies (transgastric endoscopic necrosectomy, video-assisted retroperitoneal debridement [VARD]): These result in less postoperative new-onset organ failure but require more interventions (grade 1B recommendation).

• Mortality: There is insufficient evidence to support an open surgical, mini-invasive, or endoscopic approach (grade 1B recommendation).

Consideration of the timing of cholecystectomy includes the following:

• Laparoscopic cholecystectomy during the index admission is recommended in mild acute gallstone pancreatitis (grade 1A recommendation).

• When ERCP and sphincterotomy are performed during the index admission, the risk for recurrent pancreatitis is reduced; same admission cholecystectomy is still advised owing to an increased risk for other biliary complications (grade 1B recommendation).

Open abdomen

Considerations regarding open abdominal surgery include the following:

• Clinicians should be cautious not to over-resuscitate patients with early severe acute pancreatitis and to measure intra-abdominal pressure regularly (grade 1C recommendation).

• Avoid an open abdomen if other strategies can be used to mitigate or treat severe intra-abdominal hypertension (IAH) in severe acute pancreatitis (grade 1C recommendation).

• It is recommended not to use the open abdomen after necrosectomy for severe acute pancreatitis (unless severe IAH mandates open abdomen as a mandatory procedure) (grade 1C recommendation).

• It is recommend not to debride or undertake early necrosectomy if forced to undertake an early open abdomen due abdominal compartment syndrome or visceral ischemia (grade 1A recommendation).

• The use of negative pressure peritoneal therapy is recommended for open abdomen management (grade 1B recommendation).

Timing for abdominal closure (grade 1B recommendation)

Early fascial and/or abdominal definitive closure should be the strategy for management of the open abdomen once any requirements for ongoing resuscitation have ceased, the source control has been definitively reached, no concern regarding intestinal viability persist, no further surgical reexploration is needed, and there are no concerns for abdominal compartment syndrome.