Acute pancreatitis has been top of mind for gastrointestinal researchers lately, as they have worked to refine the diagnostic process for a condition that can be life-threatening in a good percentage of patients.
First, the widely used Atlanta classification system for acute pancreatitis, devised in 1992, was updated in January 2013 (and published in Gut) to reflect advances in knowledge and to clear up confusion about terminology. The revised version states that the diagnosis has to meet at least 2 of the following criteria: severe, persistent epigastric pain that usually radiates to the back; serum lipase or amylase levels at least 3 times greater than the upper limit of normal; or evidence from contrast-enhanced computed tomography (CECT) or magnetic resonance imaging (MRI).
This year also saw 2 important guidelines published on acute pancreatitis: One in the American Journal of Gastroenterology from the American College of Gastroenterology (ACG) and the other in Pancreatology from the American Association of Pancreatology and International Association of Pancreatology. Both recommended the same criteria as the updated Atlanta classification, with the caveat that CECT or MRI of the pancreas should only be used when the diagnosis is unclear or the patient does not improve within the first 48 to 72 hours of admission.
This new guidance is important for hospitalists to commit to memory, since acute pancreatitis is a leading cause of gastrointestinal-related hospitalization, with more than 300,000 admissions in the U.S. each year, according to a paper published in the July 2007 Annals of Epidemiology. Although 85% of cases are mild to moderate and will usually resolve with general supportive care or with some interventions, the remaining 5% can be very serious, resulting in organ failure, intensive care stay and even death.
Acute pancreatitis is largely a clinical diagnosis, since other conditions have similar symptoms, said Patrick A. Rendon, MD, ACP Member, assistant professor in the department of internal medicine at the University of New Mexico in Albuquerque who has written educational materials on acute pancreatitis.
“There are multiple conditions within the abdomen that can mimic acute pancreatitis,” Dr. Rendon said. “There could be an ulcer of the stomach or duodenum, or an obstruction of the intestines. Abdominal aortic aneurysm can also occur in that area, and liver inflammation can produce similar signs.”
Because of the potential for mimics, tests are very helpful, but there are some caveats, said Santhi Swaroop Vege, MD, FACP, director of the Pancreas Interest Group and professor of medicine and consultant in the division of gastroenterology and hepatology at the Mayo Clinic in Rochester, Minn.
“Remember that amylase can be elevated with several conditions that cause abdominal pain [such as cholecystitis or intestinal blockage], and some patients with acute pancreatitis may not have elevated amylase,” said Dr. Vege, who is a coauthor of the ACG guidelines, the IAP/APA guidelines, the international consensus on management of pancreatic necrosis, and the revisions to the Atlanta classification. “Test for both amylase and lipase, but if you [have] to choose, lipase is better because it stays elevated longer.”
Older methods of trying to predict the severity of acute pancreatitis and the patient's chances of progressing to complications, such as the Ranson criteria and the Acute Physiology and Chronic Health Evaluation (APACHE) score, have fallen by the wayside in favor of the Harmless Acute Pancreatitis Score (HAPS) and the Bedside Index for Severity of Acute Pancreatitis (BISAP), said Peter R. McNally, DO, FACP, chief of gastroenterology at Evans Army Hospital in Ft. Carson, Colo.
To get the most out of these assessments, they should be done as soon as possible, Dr. McNally said: “HAPS should be assessed within 30 minutes of admission, and BISAP within 24 hours of admission. These are important because they can help you to anticipate higher mortality and triage patients to centers prepared to deal with complications.”
Both the revised Atlanta classification and a paper published in last June's Cleveland Clinic Journal of Medicine note the usefulness of assessing systemic inflammatory response syndrome (SIRS), because when SIRS is present and persistent there is an increased risk of persistent organ failure in single or multiple organs.
The ACG guidelines recommend transabdominal ultrasound for all patients with acute pancreatitis. “Ultrasound is important because that is the best test to look for gallstones, which are the most common cause of acute pancreatitis in the U.S.,” said Scott M. Tenner, MD, MPH, FACP, director of medical education and research in the division of gastroenterology at Maimonides Medical Center in Brooklyn, associate professor at the State University of New York and coauthor of ACG's guidelines.
The ACG guidelines, as well as the American Gastroenterological Association (AGA) Institute's position statement on acute pancreatitis, published in the May 2007 Gastroenterology, call for endoscopic retrograde cholangiopancreatography (ECRP) in patients with gallstone pancreatitis who also have cholangitis. However, because acute pancreatitis is a complication of ERCP, the ACG guidelines recommend pancreatic duct stents or post-procedure rectal NSAID suppositories in high-risk patients.
Once the diagnosis of acute pancreatitis is confirmed, time is of the essence, said Dr. McNally. “The first 24 hours are the golden hours of management to minimize morbidity and maximize survival.”
Adequate hydration is paramount to maintaining pancreatic microcirculation, he added. “Studies show you can decrease the absolute risk of mortality by 5% with appropriate rehydration,” Dr. McNally said. The ACG guidelines recommend 250 to 500 mL of Lactated Ringer's solution per hour unless the patient has cardiovascular, renal, hypercalcemia or other comorbidities.
“Be careful with the elderly,” said Jonathan S. Appelbaum, MD, FACP, director of internal medicine education at Florida State University College of Medicine in Tallahassee and author of ACP's Smart Medicine module on acute pancreatitis. “The elderly need rehydration, but pouring fluids in at high volume too quickly can throw these patients into congestive heart failure.”
Dr. Tenner emphasized the need for appropriate amounts of fluid relative to the size of the patient.
“If the patient is 5’4”‘ and 125 pounds and you give 200 cc per hour, that may work, but if your patient is 6’3” and 300 pounds, that's not going to be enough,” said Dr. Tenner. “A common problem is that patients don't get hydrated enough, and that's why we see more complications in larger patients.”
Both the ACP Smart Medicine module and the ACG guidelines note the need for pain management and the correction of any abnormalities in electrolytes.
There is also a need to give the pancreas a break, said Dr. Rendon. “We generally give patients no food for at least the first 24 hours, with constant reassessment. Once pain has diminished along with a decrease of nausea and vomiting, oral nutrition may be started. If they eat again too quickly, it can induce vomiting and cause inflammation, and then the [acute attack] is exacerbated,” he noted.
Dr. Rendon cautioned hospitalists treating patients with diabetes and acute pancreatitis to pay heed to nutritional status: “When patents aren't allowed to eat, you have to be careful of their blood glucose and the amount of insulin you administer. The severe stress of acute pancreatitis can also induce diabetic ketoacidosis, which can be made worse by dehydration.”
Beyond that, treatment is geared toward the cause, which in most cases is going to be either gallstones or long-term alcohol abuse. Several studies indicate that 40% to 70% of acute pancreatitis cases are caused by gallstones, and 25% to 35% are caused by long-term alcohol abuse.
“If the problem is with the gallbladder, we remove the gallbladder. If the problem is from alcohol, we counsel against drinking,” said Dr. Vege. “Other causes, such as extremely high triglycerides, should also be treated.”
Dr. Tenner cautions hospitalists to differentiate between acute alcohol abuse and chronic alcohol abuse. “This is more like a half-bottle of vodka a day for 5 or 10 years. Alcohol generally doesn't acutely cause pancreatitis or we'd have emergency rooms filled with college students every weekend,” he said. He added that alcoholics who smoke have a higher risk of developing acute pancreatitis than those who don't.
The revised Atlanta classification identifies 2 phases of acute pancreatitis, early and late, and the complications for each stage differ depending on the severity of the attack. The early phase is usually over by the end of the first week and is characterized by SIRS in mild cases.
Fortunately, most cases of acute pancreatitis are mild and will resolve with supportive care, said Dr. Rendon. “Typically our average hospital stay is 3 to 5 days.”
However, if the attack is moderate or severe, more extensive complications can be present that require more intensive treatment and a longer stay, including transient organ failure. “Approximately 20% of patients will have extra pancreatic infections, bacteremia, urinary tract infections and pneumonia. Consider more than the pancreas as a cause for fever. Look for other issues as well,” said Dr. McNally.
The late phase of acute pancreatitis, which is more likely to occur in patients with moderately severe or severe cases, is characterized by the presence of complications such as transient or permanent organ failure in the respiratory, renal or cardiovascular systems and local complications such as peripancreatic fluid collection, sterile or infected necrosis, and pseudocysts.
Complications such as pseudocysts, biliary and gastric outlet obstructions, and pancreatic duct disruption are typically treated surgically. If imaging reveals pancreatic necrosis, the focus should be on avoiding infection, with the caveat that both the ACG guidelines and the AGA Institute's position statement recommend against the use of antibiotics in sterile necrosis. For patients with infected necrosis, the ACG guidelines call for antibiotics such as carbapenems, quinolones and metronidazole.
Dr. McNally noted that acute pancreatitis will recur in up to 20% of patients, usually in the first 12 months. “That's when you look again for common things, like missed stones or alcoholism,” he said. “Run through your big list of differential diagnoses, when common causes are not detected.”