Sleep bruxism possibly triggered by multiple sclerosis attacks and treated successfully with botulinum toxin: Report of three cases.

Sleep bruxism refers to a nocturnal parafunctional activity including the clenching, grinding or gnashing of teeth. While most of the nocturnal bruxism cases seen in the general population are apparently idiopathic, it has been reported to be associated with a range of neurological diseases such as Huntington's disease, cranio-cervical dystonia and post-anoxic brain damage, but not multiple sclerosis (MS). We describe three cases of MS patients who have had moderate to severe complaints of bruxism in the two weeks following their relevant MS attacks. None of the three patients had a diagnosis of bruxism prior to her attack. The diagnosis was confirmed in one out of three by a polysomnography. One patient did not have any complaints related to bruxism previous to her attack, whereas two had mild and infrequent complaints. The symptoms of the relevant attacks were left hemihypesthesia in all and hemiparesis in two. None of the patients had spasticity that could result in severe teeth clenching. All three patients presented with morning headaches and jaw pain or tightness and were treated successfully with botulinum toxin (Btx) injections applied to their masseter and temporalis muscles. The cause of bruxism is controversial but lesions of the cortico-basalganglia-thalamo-cotrical loops are thought to be most likely. However, acute or chronic lesions in those pathways were not demonstrated in the 3 patients. It is feasible that they had normal appearing white matter interruptions in their cortico-basalganglia-thalamocortical loops along with their relevant attack.