Deterioration of palatal myoclonus after acute thalamic hemorrhage.

Background: Palatal myoclonus (PM) is the hallmark of hypertrophic olivary degeneration (HOD); however, little is known regarding the association of thalamic lesions and PM. Case presentation: Here, we report a case of deteriorative PM after an acute small ventrolateral thalamic hemorrhage in a female Chinese patient with HOD. The sudden and severe deterioration of PM was preceded by at least 10 days of an occasionally occurring PM, which was related to an acute cerebellar hemorrhage 8 months earlier. A computed tomography scan upon admission showed a small intracerebral hematoma in the left ventrolateral thalamus, and a magnetic resonance imaging scan revealed the typical signs of HOD as well as a remote lesion in the dentate nucleus. Symptoms of PM were controlled by carbamazepine and clonazepam.

Conclusion: These findings indicated that the damaged dentatothalamic tract might be due to a unique pathogenic mechanism involving a lesion of the ventrolateral thalamus and Guillain-Mollaret triangle.