Salivary duct stricture (also termed salivary duct stenosis) is narrowing of the duct of a major

salivary gland The salivary glands in mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of minor salivary glands. Salivary ...

Signs and symptoms

Strictures are the second most common cause of chronic obstructive

sialadenitis Sialadenitis (sialoadenitis) is inflammation of salivary glands, usually the major ones, the most common being the parotid gland, followed by submandibular and sublingual glands. It should not be confused with sialadenosis (sialosis) which is a non ...

, after salivary stones. In line with this, strictures may give rise to the "meal time syndrome", where there is pain and swelling of the involved salivary gland upon salivary stimulation with the sight, smell and taste of food. In other cases, there is irregular and intermittent pain and swelling of the gland which is not related to meal times. Typically the swelling is present upon waking or occurs before the first meal of the day. After several hours, the swelling goes down suddenly with a rush of foul tasting saliva. Strictures are more common in the parotid duct system compared to the submandibular duct system.

Causes

Chronic inflammation of the duct system ( sialodochitis) may cause some segments of the duct to narrow due to

fibrosis Fibrosis, also known as fibrotic scarring, is a pathological wound healing in which connective tissue replaces normal parenchymal tissue to the extent that it goes unchecked, leading to considerable tissue remodelling and the formation of perma ...

, and others to dilate. Saliva stagnates and forms a mucus plug behind the stricture during sleep when the salivary output of the parotid is reduced. Then, when salivary secretion is stimulated, the mucus plug becomes stuck in the stricture. The backlog of saliva behind the blockage causes the swelling, and the increased pressure inside the gland causes the pain. When the mucus plug is dislodged, the built up saliva is released and the swelling subsides.

Diagnosis

Strictures tend to be diagnosed based on difficulty with insertion and manipulation during sialendoscopy, or by sialography or

ultrasound Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies ...

Treatment

Treatment is by endoscopic dilation, or failing this, surgery.

Epidemiology

In one report, about 20% of individuals with mealtime syndrome had strictures upon sialography. For unknown reasons, strictures seem to be more common in females.

References

{{oral pathology Salivary gland pathology