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GENERAL CONSIDERATIONS
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Globally, pancreatic disorders, including acute and chronic pancreatitis, pancreatic cysts, and pancreatic cancer, are challenging to manage and associated with a high burden on health care resources. The relationships between these diseases continues to be poorly understood, but there is encouraging progress. Acute pancreatitis is one of the most common reasons for hospitalizations in gastroenterology, and there is increasing evidence of long-term sequelae including diabetes, exocrine pancreas insufficiency, and pancreas cancer. Chronic pancreatitis, an irreversible disease of the pancreas, is associated with poor quality of life, largely related to abdominal pain, and associated exocrine insufficiency. Pancreatic cysts, mostly incidental, are increasingly detected on cross-sectional abdominal imaging studies. Although a small number and specific types of pancreatic cysts can progress to pancreatic cancer, diagnostic uncertainty can introduce unwanted anxiety to patients and treating physicians. Meanwhile, with persistently high mortality rates, the incidence of pancreatic adenocarcinoma is increasing and is the seventh leading cause of cancer-related death in the industrialized world and the third most common in the United States.
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As emphasized in Chap. 348, the etiologies and clinical manifestations of pancreatitis are quite varied. Although it is well-appreciated that acute pancreatitis is frequently secondary to biliary tract disease and alcohol abuse, it can also be caused by drugs, genetic mutations, and trauma. In ~30% of patients with acute pancreatitis and 25–40% of patients with chronic pancreatitis, the etiology is initially unexplained.
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The global pooled incidence of acute pancreatitis is ~33.7 cases (95% confidence interval [CI], 23.3–48.8) with 1.16 deaths (95% CI, 0.85–1.6) per 100,000 person-years. The global pooled incidence of chronic pancreatitis is ~9.6 cases (95% CI, 7.9–11.8) with 0.09 attributable deaths (95% CI, 0.02–0.5) per 100,000 person-years. In the United States, the number of patients admitted to the hospital with acute pancreatitis is increasing, with estimated rates of almost 300,000 annually, whereas the number of patients hospitalized for chronic pancreatitis is decreasing, with recent estimates of ~13,000 admissions per year. Chronic pancreatitis has an annual prevalence of 42–73 cases per 100,000 adults in the United States, although higher prevalence rates (0.04–5%) have been noted among adults at autopsy. Together, acute and chronic pancreatic disease costs an estimated $3 billion annually in health care expenditures.
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The diagnosis of acute pancreatitis is generally clearly defined based on a combination of laboratory, imaging, and clinical symptoms. The diagnosis of chronic pancreatitis, especially in mild disease, is hampered by the relative inaccessibility of the pancreas to direct examination and the nonspecificity of the abdominal pain associated with chronic pancreatitis. Many patients with chronic pancreatitis do not have elevated blood amylase or lipase levels. Some patients with chronic pancreatitis develop signs and symptoms of exocrine pancreatic insufficiency (EPI), and thus, objective evidence for pancreatic disease can be demonstrated. However, there is a very large reservoir of pancreatic exocrine function. More than 90% of the pancreas must be damaged before maldigestion of fat and protein is ...