Biliary microlithiasis in patients with idiopathic acute pancreatitis and unexplained biliary pain: response to therapy.

Background and Aims: Microlithiasis has been suspected to cause acute pancreatitis and biliary pain. We studied the frequency of microlithiasis and response to treatment in recurrent idiopathic acute pancreatitis (RIAP) and unexplained biliary pain.
Methods: Gallbladder bile was examined microscopically for cholesterol monohydrate crystals (CMC) and calcium bilirubinate granules (CBG) in patients with RAIP (n = 24; mean age 36 years, range 18-56 years; 14 men), unexplained biliary pain (n = 12; mean age 32 years, range 22-55 years; six men), gallstones (n = 22; mean age 40 years, range 30-58 years; 12 men) and patients without clinical or imaging evidence of gallstone disease (n = 12; mean age 32 years, range 14-54 years; six men). The presence of a single CMC or >25 CBG/slide was considered abnormal.
Results: Bile microscopy was abnormal in 75% patients with RAIP (18/24; CMC in 10, CBG in six, CMC and CBG in two), 83.3% patients with unexplained biliary pain (10/12; CMC in seven, CBG in one, CMC and CBG in two) and 95.4% patients with gallstones (21/22; CMC in 12, CBG in one, CMC and CBG in eight). None of the controls without gallstone disease had CMC while three patients had low counts of CBG. Twenty-eight patients with RAIP and biliary pain having microlithiasis agreed to be treated with cholecystectomy (n = 2), endoscopic sphincterotomy (n = 21) or ursodeoxycholic acid (UDCA; n = 5). The 23 patients treated with cholecystectomy or sphincterotomy remained asymptomatic during follow up (mean 23 months, range 6-48 months). Four of five patients treated with UDCA remained asymptomatic for a follow-up period of 9, 10, 11 and 18 months, respectively. One patient who had refused cholecystectomy or sphincterotomy continued to experience pain at the same frequency as before during a follow-up period of 12 months. One patient, who was asymptomatic on UDCA for 9 months, agreed to undergo sphincterotomy and remained asymptomatic over a follow-up period of 14 months.
Conclusions: Microlithiasis is a common cause for idiopathic acute pancreatitis and unexplained biliary pain. Lasting relief is obtained in most patients after treatment with UDCA, cholecystectomy or sphincterotomy.