Acute pancreatitis results from premature activation of trypsinogen to trypsin within the pancreatic acinar cells, triggering a cascade of enzyme activation that leads to autodigestion of pancreatic tissue. Gallstone migration through the ampulla of Vater and chronic alcohol toxicity are the two most common causes. The inflammatory response releases cytokines (TNF-alpha, IL-6), increasing capillary permeability and causing massive third-space fluid shifts. Severe cases progress to systemic inflammatory response syndrome (SIRS), multiorgan dysfunction, and necrotizing pancreatitis. Chronic pancreatitis involves repeated inflammation leading to fibrosis, exocrine insufficiency (malabsorption), and endocrine failure (diabetes). The nurse must manage aggressive fluid resuscitation, multimodal pain control, monitor for organ dysfunction, and coordinate nutritional support.