Complications
Locoregional complications include pancreatic pseudocyst (most common, occurring in up to 25% of all cases, typically after 4–6 weeks) and phlegmon/abscess formation, splenic artery pseudoaneurysms, hemorrhage from erosions into splenic artery and vein, thrombosis of the splenic vein, superior mesenteric vein and portal veins (in descending order of frequency), duodenal obstruction, common bile duct obstruction, progression to chronic pancreatitis, pancreatic ascites, pleural effusion, sterile/infected pancreatic necrosis.Systemic complications include ARDS, multiple organ dysfunction syndrome, DIC, hypocalcemia (from fat saponification), hyperglycemia and insulin dependent diabetes mellitus (from pancreatic insulin-producing beta cell damage), malabsorption due to exocrine failure

MetabolicHypocalcemia, hyperglycemia, hypertriglyceridemiaRespiratoryHypoxemia, atelectasis, Effusion, pneumonitis, Acute respiratory distress syndrome (ARDS)Renal
Renal artery or vein thrombosis
Kidney failure
Circulatory
Arrhythmias
Hypovolemia and shock
myocardial infarction
Pericardial effusion
vascular thrombosis
Gastrointestinal
Gastrointestinal hemorrhage from stress ulceration;
gastric varices (secondary to splenic vein thrombosis)
Gastrointestinal obstruction
 Hepatobiliary
Jaundice
Portal vein thrombosis
Neurologic
Psychosis or encephalopathy (confusion, delusion and coma)
Cerebral Embolism
Blindness (angiopathic retinopathy with hemorrhage)
Hematologic
Anemia
DIC
Leucocytosis
Dermatologic
Painful subcutaneous fat necrosis
Miscellaneous
Subcutaneous fat necrosis
Arthalgia

Causes
Most common
Biliary pancreatitis due to gallstones or constriction of ampulla of Vater in 40% of cases
Alcohol in 30% of cases
Idiopathic in 15-25% of cases
Metabolic disorders: hereditary pancreatitis, hypercalcemia, elevated triglycerides, malnutrition
Post-ERCP
Abdominal trauma
Penetrating ulcers
Carcinoma of the head of pancreas, and other cancer
Drugs: diuretics (e.g., thiazides, furosemide), gliptins (e.g., vildagliptin, sitagliptin, saxagliptin, linagliptin), tetracycline, sulfonamides, estrogens, azathioprine and mercaptopurine, pentamidine, salicylates, steroids, Depakote
Infections: mumps, viral hepatitis, coxsackie B virus, cytomegalovirus, Mycoplasma pneumoniae, Ascaris
Structural abnormalities: choledochocele, pancreas divisum
Radiotherapy
Autoimmune pancreatitis
Severe hypertriglyceridemia

Less common
Scorpion venom
Chinese liver fluke
Ischemia from bypass surgery
Heart valve surgery
Fat necrosis
Pregnancy
Infections other than mumps, including varicella zoster
Hyperparathyroidism
Valproic acid
Cystic fibrosis
Anorexia or bulimia
Codeine phosphate reaction

Pathology
Pathogenesis
Acute pancreatitis occurs when there is abnormal activation of digestive enzymes within the pancreas.
Acute pancreatitis (AP) is a sudden inflammation of the pancreas. Causes in order of frequency include: 1) a gallstone impacted in the common bile duct beyond the point where the pancreatic duct joins it; 2) heavy alcohol use; 3) systemic disease; 4) trauma; 5) and, in minors, mumps. Acute pancreatitis may be a single event; it may be recurrent; or it may progress to chronic pancreatitis. Mild cases are usually successfully treated with conservative measures: hospitalization, pain control, nothing by mouth, intravenous nutritional support, and intravenous fluid rehydration. Severe cases often require admission to an intensive care unit to monitor and manage complications of the disease. Complications are associated with a high mortality, even with optimal management. Signs and symptoms
Common
severe epigastric pain (upper abdominal pain) radiating to the back in 50% of cases
nausea
vomiting
loss of appetite
fever
chills (shivering)
hemodynamic instability, including shock
tachycardia (rapid heartbeat)
respiratory distress
peritonitis
hiccupAlthough these are common symptoms, frequently they are not all present; and epigastric pain may be the only symptom.