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Acute Pancreatitis

Essentials of Diagnosis
• Abrupt onset of deep epigastric pain, often with radiation to the back.
• Nausea, vomiting, sweating, weakness
• Abdominal tenderness and distention, fever.
• Leukocytosis, elevated serum amylase, elevated serum lipase.
• History of previous episodes, often related to alcohol intake.

General considerations

Acute pancreatitis is thought to result from “escape” of activated pancreatic enzymes from acinar cells into surrounding tissues. Most cases are related to biliary tract disease (a passed gallstone) or heavy alcohol intake. The exact pathogenesis is not known but may include edema or obstruction of the ampulla of vater, resulting in reflux of bile into pancreatic ducts or direct injury to the acinar cells. Among the numerous other causes or associations are hypercalcemia, hyperlipidemias (chylomicronemia, hypertriglyceridemia, or both), abnormal trauma (including surgery), medicines (including sulfonamides and thiazides), vasculitis, viral infections (e.g. mumps), and ERCP. In patients with pancreas divisum, a congenital anomaly in which the dorsal and ventral pancreatic ducts fail to fuse, acute pancreatitis may result from stenosis of the minor papilla with obstruction to flow from the accessory pancreatic duct. Apparently “idiopathic” acute pancreatitis is often caused by occult biliary microlithiasis.

Pathologic changes vary from acute edema and cellular infiltration to necrosis of the acinar cells, hemorrhage from necrotic blood vessels, and intra and extra pancreatic fat necrosis. All or part of the pancreas may be involved.

Differential diagnosis

Acute pancreatitis may be difficult to differentiate from an acutely perforated duodenal ulcer. Other conditions to be differentiated are acute cholecystitis, acute intestinal obstruction, leaking aortic aneurysm, renal colic, and acute mesenteric vascular insufficiency or thrombosis. Serum amylase may also be elevated in high intestinal obstruction, in mumps not involving the pancreas (salivary amylase), in ectopic pregnancy, after administration of narcotics, and after abdominal surgery.