A Case of Contralateral Oculomotor Nuclear Lesion with an Isolated Superior Rectus Palsy

• Published in: JAPANESE ORTHOPTIC JOURNAL Vol. 44; pp. 91 - 95
• Main Authors: Furukawa, Shinjiro, Yamamoto, Misa, Toshima, Shinji, Terada, Yoshiko, Hara, Kazuyuki
• Format: Journal Article
• Language: Japanese
• Published: JAPANESE ASSOCIATION OF CERTIFIED ORTHOPTISTS 2015
• Subjects: contralateral oculomotor nerve palsy; crossing nerve fibers; isolated superior rectus palsy; oculomotor superior rectus subnucleus
• ISSN: 0387-5172; 1883-9215
• DOI: 10.4263/jorthoptic.044F009

[Purpose] In oculomotor nerve palsy with damaged nerve fibers, paralysis of ocular muscles often occurs on the same side as the nerve palsy. In this study, we reported a case suspected of an isolated oculomotor subnuclear lesion with symptoms of a right superior rectus palsy due to an infarction in the left midbrain. [Case] A 72-year-old man with acute onset of binocular vertical diplopia was referred to us. The MRI showed a tiny infarct inside the left midbrain. Four days after the onset, eye examination revealed corrected visual acuity of 1.2 in both eyes, eye positions at far of exotropia of 20 PD and left hypertropia of 9 PD at right fixation, exotropia of 20 PD and right hypotropia of 8 PD at left fixation by APCT. Only a superior rectus elevation palsy in the right eye was detected with the Hess chart and ocular motility examination. The vertical diplopia increased with right upward gaze. Ocular motility in the left eye was considered normal. His pupils were equal and briskly reactive to light. Considering the crossing superior rectus nerve fibers toward the contralateral side in the oculomotor nucleus, a diagnosis of a contralateral superior rectus palsy associated with an oculomotor subnuclear lesion was made. After one month, the vertical diplopia disappeared and ocular motility was normal in both eyes. [Conclusion] We had experienced a rare case of oculomotor subnuclear lesion with a contralateral isolated superior rectus palsy due to a midbrain infarction.