Upper gastrointestinal endoscopy. An unrecognized cause of hyperamylasemia.

The prevalence of hyperamylasemia 2 hr and 24 hr after upper gastrointestinal endoscopy without attempts to cannulate the ampulla of Vater was prospectively studied in 50 consecutive patients. In the 2-hr sample, hyperamylasemia was observed in nine patients (18%) (serum amylase range 59-191 units/liter with a mean value of 102 units/liter; reference range: 12-46 units/liter). Five of the nine patients still had an increased serum amylase (range 54-118 units/liter, mean 78.4) 24 hr after endoscopy. When hyperamylasemia occurred, it always appeared in and was higher in the 2-hr sample. The increased serum amylase activity was due to a rise of S-type isoamylase. The cause of hyperamylasemia after gastrointestinal endoscopy is speculative but is probably due to an hypersalivation.