Unusual pathophysiological mechanisms of ptyalism in two horses

Abstract

This report outlines two cases of ptyalism that were not associated with oral conditions or primary dysphagia. The first, a 9-year-old Thoroughbred gelding, was associated with leftsided peripheral vestibular disease and bone modelling around the left tympanic bulla. The second, a 7-year-old Dutch Warmblood mare, was associated with progressive bilateral laryngeal paralysis and a mediastinal T-cell lymphoma. In Case 1, a neurological pathophysiology was proposed involving altered autonomic innervation of the salivary glands; whilst in Case 2, the mechanism remains unclear but may have involved mechanical compression of the intrathoracic oesophagus or stimulation of afferents within the vagus nerve. This case series highlights rare causes of ptyalism that have not been previously reported in the literature. Treatment Case 1 In the absence of computed tomography of the skull or paediatric otoscope examination of the left ear to exclude otitis interna, a six-week course of doxycycline was prescribed (10 mg/kg bwt b.i.d. per os) [Karidox 1 ]. Case 2 Antimicrobial treatment with oxytetracycline (5 mg/kg bwt b.i.d. i.v.) [Engemycin 2 ] and nonsteroidal anti-inflammatory