Controversies in the etiologies of acute pancreatitis.

Acute pancreatitis is a potentially life threatening acute inflammatory condition of the pancreas with an annual incidence in the United States estimated to be 40 cases per 100,000 adults [1] which is one of the highest in the world [2]. There is also a rising trend in the incidence of acute pancreatitis in the United States which has been observed over the past several decades [3]. Though most cases are mild with mortality below 1%, there is a subset classified as severe pancreatitis in which the mortality can reach as high as 30% [4]. The direct medical cost of hospitalization for acute pancreatitis is estimated to be $2.2 billion at a mean cost per hospital day of $1,670 [5] which is likely an underestimation. To determine the etiology of the acute pancreatitis is crucial to the management of this potentially fatal condition. Even though a wide variety of etiologies have been proposed, the exact role of the some of these still remains controversial and in some cases ill-defined. A cause is not clinically determined in up to 30% of cases which are labeled idiopathic pancreatitis [6]. This review attempts to re-visit some of the controversies surrounding these etiologies, discuss the current understanding of the mechanisms that underlie them and to identify areas requiring further research.