S93 Prevalence, Etiology, and Diagnostic Evaluation of Idiopathic Acute Pancreatitis: A Real-World Analysis in Asian Population

Abstract

Introduction: Identifying the etiology is vital in management of acute pancreatitis to prevent recurrence and early detection of underlying disorder. Idiopathic acute pancreatitis (IAP) has been reported in white population to be the initial presentation of pancreatic cancer, a disease typically diagnosed at a late stage with a high mortality rate. Since investigational work up is usually deferred until the acute inflammation subsides, proper follow-up is imperative in revealing the culprit cause. This study aims to assess a real-world evaluation and causes of IAP in an Asian population. Methods: A retrospective analysis on patients discharged with a diagnosis of IAP using ICD-10 code during January 2002 to April 2020 at a tertiary care hospital was conducted. Discharge summary of the index hospitalization was reviewed to verify the diagnosis of IAP. Primary outcomes were the diagnostic modality performed and the etiology identified during the three-year follow-up period following the initial discharge. Results: Of 310 patients who were coded as IAP at discharge, 218 had an etiology identified upon discharge summary review, leaving 82 subjects (mean age 54.1 ± 17.9 years, 51.2% women) as clinically presumed IAP. 75.6% (n= 62) had at least one radiologic evaluation performed within the first year. The most common investigation was computed tomography (n= 45, 54.8 %). [Figure 1] At three-year follow-up after the first episode of IAP, 23.2% (n= 19) remained with an unknown etiology despite adherence to clinical visits and radiologic evaluation. Three patients (3.7%) were diagnosed with adenocarcinoma of the head of pancreas (2 by CT, 1 by MRI) within the first 6 months after discharge. Twenty-nine (35.4%) patients were later diagnosed with other definite cause of acute pancreatitis. [Table 1] Fourteen (17.0%) patients did not undergo further diagnostic imaging. Conclusion: Inaccurate coding of IAP at a hospital discharge substantially overestimated a true prevalence of IAP. Proper radiologic evaluation within the first year after hospitalization was crucial to identify the underlying etiology and exclude malignancy. The most common diagnostic modality done was computed tomography. Our study highlights the need of proper investigation for patients with IAP for early detection of pancreatic cancer.Figure 1.: Radiologic Evaluation during Follow-up period for presumed IAP; IAP = Idiopathic Acute Pancreatitis, CT = Computed Tomography, MRI = Magnetic Resonance Imaging, EUS = Endoscopic Ultrasound.Table 1.: Definite Cause of Acute Pancreatitis in presumed IAP Patients during Follow-up; IPMN = Intraductal Papillary Mucinous Neoplasms, PDAC = Pancreatic ductal adenocarcinoma.