Palatal myoclonus and hypertrophic olivary degeneration following Wernekinck Commissure Syndrome: a case report

Abstract

Abstract Background Hypertrophic olivary degeneration (HOD), a rare form of transsynaptic degeneration, is secondary to dentato-rubro-olivary pathway injuries in some cases. For the first time, we describe a HOD patient who presented with palatal myoclonus secondary to wernekinck commissure syndrome caused by a rare bilateral “heart-shaped” infarct lesion in the midbrain. Case presentation: A 49-year-old man presented with progressive gait instability in the past 7 months. The patient had a history of posterior circulation ischemic stroke presenting with diplopia, slurred speech, and difficulty swallowing and walking 3 years ago. The symptoms improved after treatment. The feeling of imbalance appeared and aggravated gradually in the past 7 months. Neurological examination demonstrated dysarthria, horizontal nystagmus, bilateral cerebellar ataxia, and 2–3 Hz rhythmic contractions of the soft palate and upper larynx. Magnetic resonance imaging (MRI) of the brain performed 3 years prior to this admission showed an acute midline lesion in the midbrain exhibiting a remarkable “heart appearance” on diffusion weighted imaging. MRI after this admission revealed T2 and FLAIR hyperintensity with hypertrophy of the bilateral inferior olivary nucleus. We considered a diagnosis of HOD resulting from a midbrain heart-shaped infarction, which caused wernekinck commissure syndrome 3 years ago and later HOD. Adamantanamine and B vitamins were administered for neurotrophic treatment. Rehabilitation training was also performed. One year later, the symptoms of this patient neither improved nor were aggravated. Conclusion This case report suggests that patients with a history of midbrain injury, especially Wernekinck commissure, should be alert to the possibility of delayed bilateral HOD when new symptoms occur or original symptoms are aggravated.