Acute pancreatitis with persistent organ failure lasting more than 48 hours is considered severe pancreatitis. In the early stages of the disease, organ failure starts with a systemic inflammatory response produced by the activation of a cytokine cascade, involving the continuous failure of single or multiple organs. Such patients often have one or more local complications, with organ failure that can persist for several days after onset. The mortality rate can reach 36% to 50% once organ failure occurs. Infections in such patients can dramatically increase the mortality rate. CT imaging may show gas bubbles in peripancreatic necrotic tissue and fluid collections. Diagnosis is confirmed by positive results from either a smear of aspirate obtained via image-guided fine-needle aspiration or from bacterial cultures.