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Isolated superior rectus palsy due to contralateral midbrain infarction.
Jee-Hyun Kwon1, Sun U Kwon, Hyo-Sook Ahn
1Departments of Neurology, College of Medicine, University of Ulsan, Asan Medical Center, Seoul, Korea.
Archives of Neurology
|November 19, 2003
Summary
Isolated superior rectus palsy, a rare condition causing double vision, can result from a contralateral midbrain lesion affecting nerve fibers. This finding expands our understanding of oculomotor nerve disorders.
Area of Science:
- Neuroscience
- Ophthalmology
- Neurology
Background:
- Isolated superior rectus palsy is typically associated with ipsilateral lesions.
- The occurrence of this palsy due to a contralateral midbrain lesion has not been previously documented.
Observation:
- A 71-year-old woman presented with sudden onset of diplopia (double vision).
- Clinical examination revealed isolated paresis (weakness) of the superior rectus muscle.
- Magnetic resonance imaging (MRI) identified a small infarct in the contralateral midbrain, specifically near the oculomotor nucleus.
Findings:
- The case demonstrates that a contralateral midbrain lesion can selectively impact the crossing nerve fibers responsible for superior rectus muscle function.
- This suggests a potential mechanism for isolated superior rectus palsy originating from the opposite side of the brainstem.
Implications:
- This finding broadens the differential diagnosis for isolated superior rectus palsy.
- It highlights the complex neuroanatomy of the oculomotor system and the potential for subtle lesions to cause specific deficits.
- Further research may elucidate the precise pathways involved in contralateral midbrain-induced superior rectus palsy.