Clinical Characteristics, Radiological Features, and Prognosis of Hypertrophic Olivary Degeneration Following Pontine Stroke: A Case Series

Background: Hypertrophic olivary degeneration (HOD) is a rare condition resulting from a lesion that damages the Guillain-Mollaret triangle. HOD following pontine stroke may be diagnosed late or misidentified as a recurrence or sequelae of the pontine infarction. This study aims to delineate the clinical characteristics, radiological features, and prognosis of HOD after pontine stroke. Methods: We conducted a retrospective study on individuals diagnosed with HOD subsequent to a pontine stroke at a single institution between May 2020 and July 2022. Clinical and radiological data of the patients during their hospitalization and follow-up were collected and analyzed. Results: This case series included five patients (4 males, 1 female) with an average age of 56.8 years (range: 33 to 81 years). HOD patients constituted 10.6% (5/47) of all individuals with pontine stroke. All patients exhibited prevalent cerebrovascular risk factors. Both pontine hemorrhage (60%) and pontine infarction (40%) were associated with HOD. The predominant manifestations of HOD subsequent to pontine stroke were palatal tremor (100%) and ataxia (100%), followed by Holmes' tremor (80%), ocular myoclonus (60%), and dysarthria (60%). The mean time from initial stroke to HOD diagnosis was 7 months (range: 2-10 months). Hypertrophy and hyperintense signals in the inferior olivary nuclei on T2-weighted images were observed in four cases (80%). The pontine tegmentum was the most common site contributing to HOD development (100%). Unilateral and bilateral HOD each accounted for 50% of all cases. Despite medical treatment and one-year follow-up, the prognosis remained unfavorable. CoConclusions: HOD following pontine stroke can manifest as palatal tremor, ataxia, Holmes' tremor, ocular myoclonus, and dysarthria. Classic MR image findings of HOD after pontine stroke involve hypertrophy and hyperintense signals in the inferior olivary nucleus on T2-weighted images. When new motor symptoms emerge or progressively worsen in patients post pontine stroke, HOD should be considered as a potential diagnosis. Conclusions: HOD following pontine stroke can manifest as palatal tremor, ataxia, Holmes' tremor, ocular myoclonus, and dysarthria. Classic MR image findings of HOD after pontine stroke involve hypertrophy and hyperintense signals in the inferior olivary nucleus on T2-weighted images. When new motor symptoms emerge or progressively worsen in patients post pontine stroke, HOD should be considered as a potential diagnosis. Conclusions: HOD following pontine stroke can manifest as palatal tremor, ataxia, Holmes' tremor, ocular myoclonus, and dysarthria. Classic MR image findings of HOD after pontine stroke involve hypertrophy and hyperintense signals in the inferior olivary nucleus on T2-weighted images. When new motor symptoms emerge or progressively worsen in patients post pontine stroke, HOD should be considered as a potential diagnosis.窗体底端 Conclusions: HOD following a pontine stroke can manifest as palatal tremor, ataxia, Holmes' tremor, ocular myoclonus, and dysarthria. When new motor symptoms emerge or progressively worsen in patients post-pontine stroke, especially when the lesion involves the tegmental pons, HOD should be considered as a potential diagnosis.