Periumbilical discoloration is one of the signs of acute hemorrhagic necrotizing pancreatitis. Acute hemorrhagic necrotizing pancreatitis is a type of acute pancreatitis, which is caused by the continued development of acute edematous pancreatitis lesions. There is extensive necrosis of pancreatic alveoli, fat and blood vessels, edema of pancreatic tissue, increase in size, and extensive hemorrhagic necrosis. The retroperitoneal space is heavily hemorrhagic with exudate. The omentum and tissues of the lining are digested by the exuded pancreatic enzymes. This type of pancreatitis is severe and develops rapidly, with many complications and high mortality. What are the causes of acute hemorrhagic necrotizing pancreatitis? The cause of this disease is still not well understood, mainly because of the large differences between animal models and clinical. From the data, the etiology of pancreatitis is related to the following factors. 1, obstructive factors Bile reflux due to biliary roundworm, lack of special jug abdominal stones embedded, duodenal papilla narrowing, etc. 2, alcohol factors Long-term drinkers are prone to pancreatitis, which is a common phenomenon in the West, accounting for 70%. 3, vascular factors Acute embolism and obstruction of the small arteries and veins of the pancreas, resulting in acute hemorrhagic necrotizing pancreatitis due to acute blood circulation disorders in the pancreas. 4. Trauma and medical factors Trauma to the pancreas causes rupture of the pancreatic duct, spillage of pancreatic fluid and inadequate blood supply after trauma, leading to acute heavy pancreatitis. Medical pancreatitis can occur in two cases: one occurs when doing a gastrectomy, especially in the sinus washout or duodenal posterior wall ulcers that penetrate into the pancreas, and when performing a gastrectomy, the ulcerated surface on the pancreas is scratched and forms a pancreatic leak, and the pancreatic fluid leaks out to self-digest the pancreas. Another situation is that the surgery did not affect the pancreas, but post-surgical pancreatitis occurred, which is mostly due to surgery in the adjacent organs of the pancreas, probably due to edema of the sphincter of Oddi, so that poor drainage of pancreatic fluid, damage to the blood flow of the pancreas, various reasons to stimulate the vagus nerve, so that excessive secretion of pancreatic fluid, etc. 5. Infectious factors Acute hemorrhagic necrotizing pancreatitis can occur due to various bacterial infections and viral infections, such as mumps virus, adenovirus, hepatitis A virus and bacterial pneumonia. Viruses or bacteria enter the pancreatic tissue through the blood or lymph, and cause pancreatitis. 6, metabolic diseases (1) hypercalcemia: pancreatitis caused by hypercalcemia may be related to the following factors: calcium salt deposition to form calcification in the pancreatic duct, blocking the pancreatic duct so that pancreatic fluid enters the interstitial and pancreatitis occurs; promote pancreatic secretion; trypsinogen into trypsin. (2) Hyperlipidemia: About 1/4 of patients with acute hemorrhagic necrotizing pancreatitis cases have hyperlipidemia. It may be because the small blood vessels of the pancreas are embolized by coagulated serum lipid particles, and also because high concentrations of pancreatic lipase break down serum triglycerides, releasing a large amount of free fatty acids, causing damage to the small blood vessels of the pancreas and embolization. When blood triglycerides reach 5 to 12 mmol/L, pancreatitis can occur. 7, other factors such as drug allergies, drug poisoning, hemochromatosis, adrenocorticotropic hormones, genetics, etc.