Bruxism is defined, in human medicine, as repetitive, involuntary, masticatory muscle activity, often appears as grinding teeth, bracing or thrusting of the mandible. There are two types: awake and asleep. Asleep bruxism is quite commonly reported in humans and can be triggered by stress or anxiety. Awake bruxism, or uncontrolled bruxism during awake states, is a very different thing. Awake bruxism (AB) can be broken into pathologic or physiologic causes. Physiologic causes don't apply to veterinary medicine so let's dig deeper into pathologic, awake bruxism. Within the pathologic group there are idiopathic causes and symptomatic causes. Neurologic diseases such as inflammatory conditions, traumatic or congenital disease, epilepsy and a host of other causes have been reported to be associated with awake bruxism in humans. A recent article, published in the JVIM, noted that bruxism secondary to a neurologic cause is most commonly awake bruxism.
Have you seen a dog with Bruxism? The recent article by Liatis T, et al, evaluated AB in 4 dogs over a span of 11 years so don't feel badly if you've not seen one! A link to the entire report is found at the bottom. Although previously reported in dogs with congenital storage disorders, it is rare in mature adult dogs. In this study, two dogs were presented by the owners with a complaint of AB, along with other clinical signs of neurologic disease. AB was noted in the second two dogs by the attending clinicians during evaluation. AB was episodic in all four dogs, occurring throughout the day and always stopped when distracted. No post ictal signs were noted and no autonomic signs were seen during or after the event. All four dogs had forebrain lesions!
Take away: If you evaluate a dog for awake bruxism, or if you note it during the exam while evaluating the pet for other neurologic abnormalities, consider it abnormal. It is not pathognomonic for forebrain disease but, at least according to this report, is strongly supportive of a forebrain lesion. This may be an indication to get a neurology consultation and advanced imaging.
Link: https://onlinelibrary.wiley.com/doi/full/10.1111/jvim.16570?campaign=wolearlyview
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