Pearls & Oy-sters: Oculopalatal tremor with one-and-a-half syndrome after pontine hemorrhage

Abstract

1. The palatal myoclonus in symptomatic cases is usually silent as the involved muscle is the levator veli palatini. This is in contrast to the audible clicking sound (generated by the synchronous collapse of the eustachian tube) in patients with essential palatal myoclonus in which the involved muscle is the tensor veli palatini. 2. The hyperintense signal on T2-weighted MRI in transneuronal hypertrophic degeneration of the inferior olivary nucleus reflects increased water content and gliosis. Enlargement of the inferior olivary nucleus results from astrocytic hypertrophy and vacuolar cytoplasmic degeneration. Eventually, permanent atrophy of olivary neurons ensues within 3 to 4 years. A 63-year-old man with a history of treated hypertension presented with sudden onset of right hemiparesis and horizontal diplopia that was worse on rightward gaze. His blood pressure was 220/120 mm Hg. On neurologic examination, the patient had a right hemiplegia. Examination of the extraocular movements demonstrated conjugate left lateral gaze palsy, impaired adduction of the left eye, and abduction nystagmus of the right eye. These signs were consistent with a left “one and a half syndrome.” Further assessment revealed a bilateral facial nerve palsy of the lower motor neuron type. The cranial CT revealed intraparenchymal brainstem hemorrhage involving the left side of the pontine tegmentum with extension into the fourth ventricle (figure 1). His motor weakness and the facial diplegia improved, but the extraocular eye movements remained limited with persistent horizontal diplopia, particularly on rightward gaze. Figure 1 Initial CT of the head showing the intraparenchymal brainstem hemorrhage that mainly involved the left side of the pontine tegmentum with extension into the fourth ventricle Six months later, he presented again with a precipitous onset of oscillopsia …