Update on pathogenesis and clinical management of acute pancreatitis.

Acute pancreatitis (AP), defined as the acute nonbacterial inflammatory condition of the pancreas, is derived from the early activation of digestive enzymes found inside the acinar cells, with variable compromise of the gland itself, nearby tissues and other organs. So, it is an event that begins with pancreatic injury, elicits an acute inflammatory response, encompasses a variety of complications and generally resolves over time. Different conditions are known to induce this disorder, although the innermost mechanisms and how they act to develop the disease are still unknown. We summarize some well established aspects. A phase sequence has been proposed: etiology factors generate other conditions inside acinar cells that favor the AP development with some systemic events; genetic factors could be involved as susceptibility and modifying elements. AP is a disease with extremely different clinical expressions. Most patients suffer a mild and limited disease, but about one fifth of cases develop multi organ failure, accompanied by high mortality. This great variability in presentation, clinical course and complications has given rise to the confusion related to AP related terminology. However, consensus meetings have provided uniform definitions, including the severity of the illness. The clinical management is mainly based on the disease´s severity and must be directed to correct the underlying predisposing factors and control the inflammatory process itself. The first step is to determine if it is mild or severe. We review the principal aspects to be considered in this treatment, as reflected in several clinical practice guidelines. For the last 25 years, there has been a global increase in incidence of AP, along with many advances in diagnosis and treatment. However, progress in knowledge of its pathogenesis is scarce.