Idiopathic acute pancreatitis: a review on etiology and diagnostic work-up.

Acute pancreatitis (AP) is a common disease associated with a substantial medical and financial burden, and with an incidence across Europe ranging from 4.6 to 100 per 100,000 population. Although most cases of AP are caused by gallstones or alcohol abuse, several other causes may be responsible for acute inflammation of the pancreatic gland. Correctly diagnosing AP etiology is a crucial step in the diagnostic and therapeutic work-up of patients to prescribe the most appropriate therapy and to prevent recurrent attacks leading to the development of chronic pancreatitis. Despite the improvement of diagnostic technologies, and the availability of endoscopic ultrasound and sophisticated radiological imaging techniques, the etiology of AP remains unclear in ~ 10-30% of patients and is defined as idiopathic AP (IAP). The present review aims to describe all the conditions underlying an initially diagnosed IAP and the investigations to consider during diagnostic work-up in patients with non-alcoholic non-biliary pancreatitis.