RESUMEN
Patients admitted with the diagnosis of AP to a clinical hospital were included in the study. According to an abdominal ultrasound study, patients were classified as having or not cholelithiasis. A duodenal biliary drainage was performed in 15 patientes with AP and without gallbladder stones. Results: Patients without cholelithiasis had recurrent AP more often than patients with biliary AP (53 and 3.3 percent respectively). Excessive alcohol ingestion did not rule out the possibility of biliary etiology. In 6 patients, the analysis of duodenal bile showed cholesterol crystals, and cholecystectomy confirmed the existence of gallbladder disease in 54. All of them remained asymptomatic during a follow-up period of four years. One patient refused surgery, with subsequent development of galls tones and recurrent episodes of AP. In other 4 patients, gallbladder disease was confirmed by percutaneous gallbladder puncture or during cholecystectomy. No recurrence of AP were observed during the follow-up. Conclusions: Microlithiasis or "occult" gallbladder disease accounts for at least 67 percent of the original "non-biliary" AP. Duodenal bile analysis is a useful and necessary technique for the evaluation of patients with "non-biliary" actue pancreatitis. Careful clinical and echographic follow-up of this subgroup of patients with AP is mandatory