Chronic nonpathological hyperamylasemia of pancreatic origin

Pancreatic hyperamylasemia is usually an expression of pancreatic disease. This study describes pancreatic hyperamylasemia in the absence of pancreatic disease.

Eighteen subjects with this form of hyperamylasemia were referred to our unit from January 1987 to June 1991. Amylase and pancreatic isoamylase as well as serum lipase and trypsin concentrations were determined, and ultrasonography and computed tomography were performed in all patients. After initial evaluation, they were seen annually for clinical assessment, ultrasonography, and serum enzyme determination until December 1995. At the final evaluation, all underwent a pancreatic function study.

In 14 of the 18 subjects, all enzyme levels assessed were abnormally elevated; in 3 subjects, all but the lipase level were abnormally elevated, and in the remaining subject, all but the trypsin level were abnormally elevated. The increase over the upper normal limit was in the range of 1.4-4.1-fold for amylase, 1.8-6-fold for pancreatic isoamylase, 1.5-7.7-fold for lipase, and 1.6-13.9-fold for trypsin. During follow-up, enzyme concentrations remained elevated, although wide fluctuations and occasional transient normalization were observed. No subjects had evidence of pancreatic disease either at initial evaluation or during follow-up.

This is the first detailed description of chronic nonpathological pancreatic hyperamylasemia as a distinct entity. The reasons for this enzyme alteration are unknown.