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 symptoms that are easily confused with it? 1, acute gastroenteritis Acute gastroenteritis is a very common acute gastrointestinal disease, characterized by a clear history of improper diet, sudden onset and rapid recovery, often manifested as nausea, vomiting, abdominal pain, diarrhea, etc. 2, acute perforation of ulcer disease Acute perforation of ulcer disease is one of the serious complications of ulcer disease. In all patients with ulcer disease, acute perforation accounts for about 10-15%. The vast majority of ulcer perforations are duodenal ulcer perforations. The ratio of acute perforation of ulcer disease is 15:1. Acute perforation of ulcer disease has a rapid onset and changes quickly, if not treated in time, it can be life-threatening due to peritonitis. 3. Gallstones Gallstones are stones formed in the bile duct. The dissolved components of the bile become non-soluble for some reason, forming crystals or precipitating out to form stones. According to their main components, they can be divided into three categories: cholesterol stones, bile pigment stones and rare stones with other components. The causes of gallstones include metabolic abnormalities, bile stagnation, and biliary tract infection. Cholesterol and bile pigment are insoluble in water, but they are dissolved in microcolloid form by the action of bile acids and lecithin. The above mentioned pathogenic factors change the composition of bile, such as the decrease of bile acid, the gelatinous state is changed, and the dissolved particles are analyzed and formed into gallstones. Gallstones can also be found in other animals, and the Chinese medicine cow’s bile is a bovine gallstone. 4, acute cholecystitis Acute cholecystitis is an inflammation of the gallbladder caused by obstruction of the gallbladder duct and bacterial invasion; its typical clinical features are paroxysmal colic in the right upper abdomen, accompanied by obvious tenderness and abdominal muscle tonicity. About 95% of patients have gallbladder stones, called lithotriptic cholecystitis; 5% of patients do not have gallbladder stones, called non-lithotriptic cholecystitis. Cholecystitis is a common disease.