The main symptom of severe pancreatitis is abdominal pain. This type of abdominal pain manifests as intense pain in the upper-middle abdomen, which radiates to the back and both sides of the body. The pain is widespread and severe, with about 95% of patients experiencing abdominal pain. Onset often occurs following binge eating or excessive drinking, and the pain worsens after eating. Another symptom is abdominal distension, which is also a common symptom. It is caused by extensive effusion in the abdominal cavity and retroperitoneum, as well as intestinal paralysis. Fever in the early stage of the disease is also a common symptom, resulting from the absorption of a large amount of necrotic tissue. Fever occurring in the later stages is often caused by infections triggered within the abdominal cavity.