Clinical Features of Lateral Medullary Infarction with Ipsilateral Hemiparesis (P03.026)

Objective: To clarify clinical features and lesion distribution of lateral medullary infarction (LMI) with ipsilateral hemiparesis (IH). Background LMI with hemiparesis ipsilateral to the lesion was first reported by Opalski in 1946. He explained IH with the damage of pyramidal tracts at the level of upper cervical cord. However, little is known about the clinical features and MRI profiles. Design/Methods: We performed a single-hospital-based retrospective study. Subjected were 69 LMI patients admitted to our hospital within a week after stroke between January 1998 and July 2011. All the LMI lesions were confirmed with diffusion-weighted MRI. Excluded were 16 patients who had other lesions possibly causing IH or did not have detailed clinical information. The remaining 53 patients (mean age 59.9 yrs, 38 males) were divided into two groups, IH and non-IH. The medulla oblongata and upper cervical cord were divided into 5 areas (upper medulla, middle medulla, lower medulla, cervico-medullary junction and upper cervical cord). Results: Seventeen patients (32.1 %) showed IH (IH group), while the other 36 had no motor weakness (non-IH group). Clinical profiles including age and gender were similar between the two groups. The severity of paresis was mild to moderate in all IH patients. The incidence of vertebral artery dissection was significantly higher in IH group than in non-IH group (58.5% vs. 27.8%, p Conclusions: IH was a relatively common symptom in LMI. The lower medulla instead of the upper cervical cord was most frequently involved in our IH patients. LMI with IH may represent distinct clinical entity characterized by a long extending lower medullary lesion. Disclosure: Dr. Uemura has nothing to disclose. Dr. Uno has nothing to disclose. Dr. Umesaki has nothing to disclose. Dr. Miyashita has nothing to disclose. Dr. Nagatsuka has nothing to disclose. Dr. Toyoda has nothing to disclose. Dr. Minematsu has nothing to disclose. Dr. Naritomi has nothing to disclose.