Hypertrophic olivary degeneration: retrospective study on six cases and literature review

Objective To study the clinical characteristics of hypertrophic olivary degeneration (HOD). Methods Clinical data from 6 HOD patients, diagnosed and treated in Department of Neurology of the First Affiliated Hospital of Zhengzhou University from January 2013 to December 2018, were retrospectively analyzed, and patients were followed up once by telephone. Results There were 4 cases of unilateral HOD and 2 cases of bilateral HOD. Clinical manifestations were ataxia in 5 patients, limb tremor in 3 patients, bilateral eyeball tremor in 2 patients, bilateral palatal muscle tremor in 1 patient, limb pain in 1 patient, systemic myoclonus in 1 patient, diplopia in 1 patient. Magnetic resonance imaging (MRI) showed high signal on T2 weighted imaging, slightly low signal or isointensity signal on T1 weighted imaging. Susceptibility weighted imaging (SWI) were performed on 3 patients, and no significant increase in the density of the red nucleus was found. One patient presented hyperintensity on fluid-attenuated inversion recovery (FLAIR). One patient underwent enhanced MRI, but no enhancement in the inferior olivary nucleus was found. Conclusions In addition to typical symptoms, HOD also presents atypical symptoms. MRI can clearly show the secondary degeneration of olive nucleus, and SWI can not show the red degeneration. The effect of medicine on limb tremor is not good. The overall prognosis is poor, but limbs tremor symptoms of some patients can be improved with time. Key words: Hypertrophic olivary degeneration; Magnetic resonance imaging; Susceptibility weighted imaging