In 10% to 30% of patients with acute pancreatitis (AP), a cause will not be identified after a careful history, physical examination, laboratory testing, and radiological evaluation. These patients are classified as having idiopathic acute pancreatitis (IAP). Two recent studies (Gastroenterology 1991;101:1701; NEJM 1992;326:589) suggested that 67-75% of patients had microlithiasis as the cause for their IAP. The aim of this study was to determine the frequency of cholesterol crystals (CC) and calcium bilirubinate granules (CBG) (markers for sludge and microlithiasis) in bile in a cohort of patients (with the gallbladder in situ) referred for ERCP evaluation of IAP. METHODS: During the past 5 years, 37 patients with IAP, a normal ERCP, serum hepatic chemistries <2 times upper limits of normal on presentation, and the gallbladder in situ underwent evaluation of their bile for crystals. Minimal criteria for the diagnosis of AP included acute upper abdominal pain (without another identified cause) and serum amylase/lipase >3 times the upper limits of normal usually associated with pancreatitis changes on CT scan and/or ultrasound. Gallstones or sludge were not seen on ultrasound and/or CT scan. Sphincter of Oddi manometry (SOM) was performed in 33 patients (successful in 31) in the standard retrograde fashion using the aspirating catheter. Sphincter of Oddi dysfunction (SOD) was diagnosed when the basal sphincter pressure was ≥40 mmHg. Bile was collected directly from the gallbladder (n=6) after cystic duct cannulation with aid of a glidewire or from the common bile duct (n=31) following intravenous Kinevac (3 ug) infusion. Fresh bile was evaluated by light and polarizing microscopy after centrifugation at 3000g for 10 minutes. RESULTS: This table shows the number of patients with CC or CBG of the total number of patients with a given SOM result. SOM SOM Normal Abnormal Failed Not Done 1/17 0/14 0/2 0/4 CC (n=1) and CBG (n=0) were found in 1 of 37 IAP patients (2.7%). Biliary crystals were found in no patients with SOD and one patient (5.9%) with a normal SOM. CONCLUSIONS: In this cohort of IAP patients referred for ERCP evaluation, microlithiasis was an infrequent (potential) etiology of the AP. These findings suggest that patients who have normal (or near normal) serum hepatic chemistries at the time of their episode of AP have a very low likelihood of harboring microlithiasis.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging