Idiopathic acute pancreatitis: a single-center investigation of clinical and biochemical features.

Acute pancreatitis (AP) is termed as idiopathic (IAP) when the underlying conditions of pancreatic inflammation remain unknown. The aim of this study was to identify different clinical features in patients with IAP and AP of known aetiology. All patients hospitalized in our Gastroenterology Unit with an initial diagnosis of AP were recruited. AP was classified as of known aetiology or idiopathic according to clinical examination, serum biochemistry testing, and radiological imaging investigations, and clinical data in both patient groups were compared. A total of 127 patients (80 males, mean age: 57 years) were eligible for the analysis, 92 of which (73%) with AP of known aetiology and 35 (27%) with IAP. The major causes of AP were biliary obstruction (65%) or alcohol abuse (25%). Previous cholecystectomy was more frequent in patients with AP of known aetiology than in patients with IAP (14% versus 0%); patients with IAP showed lower gamma-glutamyl transpeptidase levels, lower daily alcohol intake, and higher frequency of gastroenteritis than patients with AP of known aetiology (34.3% versus 15.2%). Previous intake of nonsteroidal anti-inflammatory drugs was more frequent in patients with IAP than in patients with AP of known aetiology (23% versus 0%). No further differences in clinical features were found between the two patient groups. IAP accounts for almost 20% of cases of AP. An association of AP with gastroenteritis or the use of NSAIDs should be considered if time-related with disease onset, especially in patients with no recurrent attacks.