How does pancreatitis cause the pancreas to digest its own tissue?

Pancreatitis causes the pancreas to digest its own tissue through the premature activation of digestive enzymes within the organ itself.1

Normally, the pancreas produces zymogens—inactive enzyme precursors—that are safely transported to the small intestine before being activated. However, in cases of pancreatitis, factors such as ductal obstruction (e.g., by gallstones) or heavy stimulation of acinar cells can damage the pancreas's fine ductal network.231

This damage allows these powerful enzymes to escape into the substance of the pancreas. Furthermore, overstimulation of the acinar cells can trigger intracellular enzyme systems, converting proenzymes into active forms while still inside the gland. Once activated, these enzymes begin to digest cellular organelles and surrounding tissues, leading to inflammation, necrosis, and the self-destruction of the gland.14