LOS ANGELES—Timely diagnosis and treatment are essential in cases of gallstone pancreatitis, a tricky ailment that assumes a severe, necrotizing form in up to 25% of patients.
“This is a very serious disease, particularly in [those] patients who generally have a normal pancreas,” Kenneth F. Binmoeller, M.D., said at the 12th International Symposium on Pancreatic and Biliary Endoscopy sponsored by the Cedars-Sinai Medical Center.
Physicians should suspect gallstones in every acute pancreatitis patient with risk factors for gallstone disease, advised Dr. Binmoeller, director of interventional endoscopy at California Pacific Medical Center in San Francisco.
Many drugs heighten the risk of gallstone formation, including clofibrate, octreotide, ceftriaxone, and estrogens. Furthermore, laparoscopic cholecystectomy can cause stones to be milked from the cystic duct or the neck of the gallbladder into the common bile duct.
“If a patient develops pancreatitis a few days after [laparoscopic gallbladder surgery], you definitely want to think about gallstone pancreatitis,” he said.
Studies have shown that only one laboratory parameter—alanine aminotransferase greater than three times normal limits—has more than 95% sensitivity for diagnosing acute biliary pancreatitis. Bilirubin and alkaline phosphatase may rise because of extrinsic bile duct compression secondary to pancreatitis, so abnormal laboratory values are not diagnostic.
Because very small stones, especially at the ampulla of Vater, are most likely to cause biliary pancreatitis, the best diagnostic imaging modality for this indication is endoscopic ultrasound (EUS). “Here we get marvelous images of the bile duct,” Dr. Binmoeller said, pointing out tiny stones that could be missed on transabdominal ultrasound, computed tomography, or magnetic resonance cholangiopancreatography (MRCP).
Another advantage of EUS is its ability to image the ampulla both ultrasonographically and endoscopically.
Studies have shown that MRCP has 100% sensitivity with stones larger than 1 cm, he noted. But it has a much lower sensitivity in detecting small stones: 89% for stones 5-10 mm, and 71% for those smaller than 5 mm. Artifacts can make MRCP images milky, obscuring visualization of small stones and sludge shown clearly on EUS.
Unfortunately, neither EUS nor MRCP is widely available on an urgent basis, so some stones may go undetected when a patient presents with possible gallbladder pancreatitis. Nor is the best management strategy always clear.
A series of trials in the United Kingdom, Hong Kong, and Germany reached conflicting conclusions about the benefits and risks of urgent endoscopic retrograde cholangiopancreatography (ERCP) with or without sphincterotomy. A multicenter study in Germany found no outcome benefit and higher mortality in patients who underwent early ERCP compared with those managed conservatively, a conclusion that was “a real jolt to the whole endoscopic community,” Dr. Binmoeller said (N. Engl. J. Med. 1997;336:237-42).
Several methodologic problems plagued that study and the others, however, so the salient question remains: Is sphincterotomy more efficacious than conservative management in patients with severe pancreatitis without jaundice?
Until a well-designed study answers that question, Dr. Binmoeller proposes the following management algorithm, which he uses in his practice:
▸ Patients presenting with acute pancreatitis associated with a bilirubin value of more than 3 mg/dL or cholangiosepsis should undergo urgent ERCP with sphincterotomy and sweeping of the bile duct, regardless of whether a stone is seen on cholangiography.
▸ In the absence of the above criteria, patients should undergo at least a duodenoscopy for visualization of the ampulla and, if possible, EUS. An ERCP and sphincterotomy should be performed if pus or a bulging, edematous papilla is seen on duodenoscopy or if EUS reveals an impacted stone.n
A small impacted stone has been freed from the ampulla after sphincterotomy.
Endoscopic ultrasound detects stones too small to see with other techniques.