Hyperamylasemia in bulimia nervosa and hyperemesis gravidarum

The exact causes of hyperamylasemia detected in bulimia nervosa are unknown but it is presumed to be due either to repeated binging or to vomiting. This study set out to investigate the importance of vomiting in producing the raised serum amylase and to clarify whether the amylase in pancreatic or salivary.

Patients suffering from hyperemesis gravidarum who were repeatedly vomiting in pregnancy but not binge eating had their total serum and pancreatic amylase measured. Bulimic patients and a control sample of nonvomiting pregnant women were similarly studied. An assessment of the frequency and duration of vomiting and binging was also made.

Results show 45% (5) of bulimic patients had raised serum amylase, but none had a raised pancreatic amylase. Twenty-four percent (7) of the hyperemetic patients also had a raised serum amylase level, all with a normal pancreatic amylase level. None of the nonvomiting pregnant patients had a raised amylase.

Of patients with hyperemesis gravidarum who repeatedly vomit but do not binge, a significant number had raised amylase. This suggests that it is the vomiting rather than the binge behavior that increases amylase in bulimic patients. This increased amylase probably comes from the salivary gland.