Changes in Serum Amylase Levels Caused by Sialography

Abstract

This study was designed to clarify the degree and duration of tissue injury caused by sialography, and the mechanism of the increase of serum amylase levels which has been noted in various diseases of the salivary glands.
Sialography was performed in 20 normal subjects and 58 patients with parotid gland disorders: Sjögren's syndrome (11 patients), sialosis (10 patients), abnormal dilatation of the main duct (8), chronic recurrent infantile parotitis (6), chronic parotitis (2), benign tumor (4) and others (17). In addition 7 normal submandibular glands were examined.
Before and after sialography, amylase levels were determined in the serum and urine, and biopsies of the glands were taken for histological examination.
1. Increases in serum and urine amylase levels reached a peak one day after sialography and then fell slowly for one or two weeks.
2. The amount of increase was significantly less than normal in Sjögren's syndrome, chronic recurrent infantile parotitis, chronic parotitis and dilatation of the main duct.
3. Amylase levels after sialography of the submandibular gland were significantly lower than after that of the parotid gland.
4. The major histological change after sialography was periductal small round cell infiltration (especially around the striated duct).
The present results indicate that tissue injury due to sialography is slight and easily reversible in one or two weeks. The increased ability of the striated duct to reabsorp salivary amylase may be one of mechanisms of increase of serum amylase levels in salivary gland diseases. In spite of the increased reabsorption, reduced secretion of amylase by the secretory cells does not raise the serum amylase level.