Acute Pancreatitis

Excerpt

Acute pancreatitis is a common and potentially serious condition marked by abrupt inflammation of the pancreas. This condition is the leading cause of hospitalization for gastrointestinal disease in the United States, accounting for more than 275,000 hospital admissions annually. The clinical course varies from mild, self-limited inflammation to severe disease with necrosis, systemic inflammatory response syndrome, multiorgan dysfunction syndrome, and high mortality.

Mortality depends on disease severity, ranging from approximately 3% in mild interstitial pancreatitis to 20% in necrotizing forms. Although diagnosis is typically based on characteristic symptoms and elevated pancreatic enzymes, predicting clinical progression and long-term outcomes remains difficult. Early identification of high-risk patients is critical to determining the appropriate level of care, the need for intensive monitoring, and the timing of targeted interventions.

The Revised Atlanta Classification provides standardized terminology for the morphological subtypes and severity of acute pancreatitis (see Table. Morphologic Subtypes of Acute Pancreatitis Based on the Revised Atlanta Classification). Interstitial edematous pancreatitis involves inflammation of the pancreatic parenchyma and peripancreatic tissue without necrosis. This form is more common and generally less severe. In contrast, necrotizing pancreatitis includes varying degrees of pancreatic parenchymal or peripancreatic necrosis and is associated with a higher risk of complications and poorer clinical outcomes (see Image. Necrotizing Pancreatitis with Extensive Peripancreatic Nodularity).

Severity is categorized into 3 clinical grades (see Table. Severity Staging of Acute Pancreatitis Based on the Revised Atlanta Classification). Mild acute pancreatitis is defined by the absence of organ failure and local or systemic complications. Moderately severe disease involves transient organ failure lasting less than 48 hours or local or systemic complications such as peripancreatic fluid collections. Severe acute pancreatitis is marked by persistent organ failure exceeding 48 hours, often involving multiple organ systems.

The pancreas is a retroperitoneal gland extending from the duodenum to the splenic hilum between the L1 and L2 vertebrae. This organ has 4 regions—the head, neck, body, and tail—and lies transversely along the posterior abdominal wall. The pancreas serves both exocrine and endocrine functions, with digestive enzymes delivered via the pancreatic ducts to the duodenum and hormonal products such as insulin, glucagon, and somatostatin secreted by the islets of Langerhans. Thorough knowledge of acute pancreatitis's classification, anatomy, and clinical spectrum supports accurate diagnosis, enables early risk stratification, and guides appropriate interprofessional management. These core elements influence prognosis and inform inpatient and outpatient care decisions.