Sialolithiasis
What is sialolithiasis?
Takeaways
- Sialolithiasis is the formation of salivary stones (sialoliths), hard, moveable masses that form around an item such as a small piece of grass in the salivary duct.
- Sialoliths grow as layers of calcium are added over time.
- Sialoliths can cause ulcerations on the inside of the cheeks, which can lead to inflammation, infection, and difficulty eating, among other issues.
- Treatment for sialolithiasis involves surgical removal of the stone(s).
- Recurrence of sialolithiasis after surgery has been reported in 24% of cases, most commonly occurring within three years.
Sialolithiasis, or the formation of salivary stones (sialoliths), is not very common in horses. These hard, moveable masses typically start small, forming around an item such as a small piece of grass that finds its way into the parotid salivary duct and grow as layers of calcium are added over time (similar to how enteroliths form). As they get larger, they can rub on the insides of the cheeks, causing ulcerations. This can in turn lead to inflammation, infection, and difficulty eating. If saliva production becomes altered, digestion may be affected.
Cases of sialolithiasis have been reported in a variety of breeds, and affect both males and females. The disease affects horses across a wide range of ages (two to 29 years of age), but appear to be most frequently observed in horses over 16 years of age.
What are the clinical signs of sialolithiasis?
Horses affected with sialolithiasis can remain asymptomatic for long periods of time. One study reported that the duration of clinical signs ranged from two days to seven years (with an average time of 18 months). Obstruction of the salivary gland by the sialolith can cause noticeable localized facial swelling that may or may not be painful. Whereas facial swelling is the most common clinical sign, additional clinical signs may include losing or spitting out balls of semi-chewed food (quidding), draining tracts in the skin, bad breath (halitosis), fever, difficulties eating (inappetence) and swallowing (dysphagia), weight loss, facial nerve paralysis.
How is sialolithiasis diagnosed?
The presence of sialoliths may be suspected based on physical and dental examinations and can be diagnosed by imaging with x-rays or ultrasound, as well as cytology and culture of saliva samples.
How is sialolithiasis treated?
Treatment for sialolithiasis involves surgical removal of the stones. This surgery can often be performed under standing sedation and most horses recover quickly.
What is the prognosis for sialolithiasis?
The prognosis for most affected horses is excellent upon removal of the sialolith(s). Complications can include infection of the surgery site, the formation of fistulas (draining tracts) and potential damage to the facial artery and vein. One study reported recurrence of sialoliths after surgical removal in 24% of cases, with the average time to recurrence noted as just under three years after surgery, with the range reported as one to five years.
How can sialolithiasis be prevented?
Some reports have implicated diet in the formation of sialoliths, but more research is needed to determine the exact cause(s) of this disease. There are currently no clear measures to prevent sialolithiasis.
For more information
Oreff GL, Shiraki R, Kelmer G. Removal of sialoliths using the intraoral approach in 15 horses. Can Vet J. 2016;57(6):647-650.
Carlson N, Eastman T, Winfield L. Sialolithiasis in horses: A retrospective study of 25 cases (2002-2013). Can Vet J. 2015;56(12):1239-1244.
*This article may not be reproduced without the written consent of the UC Davis Center for Equine Health. Please email requests to cehadmin@ucdavis.edu.