Xerostomia refers to a dry mouth caused by a decreased salivary gland flow in a patient with adequate hydration. It may occur as an isolated finding or as one of the findings in Sjogren's syndrome.

Objective criteria for the diagnosis of xerostomia - at least 2 of the following:

(1) reduced unstimulated salivary flow, with <= 1.5 mL saliva collected in 15 minutes

(2) lymphoplasmocytic infiltrate in an adequate biopsy of labial salivary glands (sialoadenitis)

(3) abnormal salivary gland imaging studies (scintigraphy):

(3a) decreased uptake

(3b) decreased spontaneous secretion

(3c) decreased secretion after citrus stimulation


Problems in diagnosis:

(1) Some patients complain of a dry mouth despite evidence of adequate saliva flow.

(2) An inadequate biopsy may miss or insufficiently sample a minor salivary gland.

(3) While biopsy of the parotid gland may be diagnostic, this can result in facial nerve damage, scarring or a cutaneous fistula if not performed carefully.


Differential diagnosis:

(1) Sjogren's syndrome

(2) dehydration

(3) obstruction to saliva flow (stone, tumor)

(4) drug effect or infection

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