Images in Clinical Medicine
Pendular Nystagmus and Palatomyoclonus from Hypertrophic Olivary Degeneration
N Engl J Med 2009; 360:e12February 26, 2009
- Article
Video
Pendular Nystagmus (Video 1) and Palatomyoclonus (Video 2).
A 50-year-old woman with hypertension had an acute pontine hemorrhage, as seen on computed tomography (Panel A, arrow), which resulted in quadriplegia. Thirty months later, she reported having difficulty reading because of oscillopsia. The physical examination revealed pendular nystagmus (two cycles per second) with a predominantly vertical component and some horizontal and torsional eye movements (Video 1). She also had palatomyoclonus, seen as rhythmic, involuntary contractions of the soft palate and pharyngopalatine arch (one to two cycles per second) (Video 2). T2-weighted magnetic resonance imaging of the brain showed hyperintensity and enlargement of the inferior olivary nuclei, findings that were compatible with a diagnosis of hypertrophic olivary degeneration (Panel B, arrowheads). The condition, which may be caused by trauma, infection, demyelination, neoplasm, or vascular injury in the components of the dentatorubroolivary pathway, results in olivary hypertrophy rather than atrophy. Myoclonic contractions of the soft palate and nystagmus represent the effects of transsynaptic degeneration of the inferior olivary nuclei. After treatment with trihexyphenidyl, there was some improvement in the patient's visual symptoms.
C.C. Tchoyoson Lim, M.D.
Su Ann Lim, M.D.
National Neuroscience Institute, Singapore 308433, Singapore
tchoyoson_lim@nni.com. sg
