Delayed-onset continuous bruxism with olivary hypertrophy after top of the basilar syndrome

Abstract

Delayed-onset continuous bruxism due to brain stem infarction has not yet been reported. A 49-year old man presented with quadriplegia and ophthalmoplegia. Brain MRI showed acute infarction in the bilateral midbrain, right thalamus and the superior cerebellum. One month later, the patient developed bruxism which persisted during sleep. A palatal myoclonus was not observed. Follow up MRI taken 4 months later showed bilateral olivary hypertrophy. We suggest that the patient's bruxism may be related to the olivary hypertrophy. The bruxism generator may be located in the pontine-reticular-formation (PRF). Bilateral large midbrain lesions interrupting the cortical inhibition may have produced bilateral olivary hypertrophy, which could stimulate the PRF, producing continuous bruxism.

Keywords: Bruxism; Olivary hypertrophy; Pontine reticular formation.

Figure 1

MRI findings at the onset of infarction (A). Acute infarction was observed in the bilateral midbrain, right median thalamus, and superior cerebellum. Follow-up T2-weighted MRI performed four months later revealed bilateral olivary hypertrophy (B). T2-weighted MRI performed eight months after the infarction revealed persistent olivary hypertrophy (C).