Rinsho Shinkeigaku (Clinical Neurology)

Brief Clinical Note

Isolated crossed superior rectus palsy in a midbrain infarction

Tetsuro Tsukamoto, M.D.1), Mitsuharu Yamamoto, M.D.2), Takahisa Fuse, M.D.2) and Masahiko Kimura, M.D.3)

1)Department of Neurology, Numazu Rehabilitation Hospital
2)Department of Neurosurgery, and 3)Department of Ophthalmology, National Hospital Organization, Shizuoka Medical Center

A 61-year-old man suddenly heard tinnitus and diplopia at night during watchinng television. A few days later he visited at our hospital. Neurologically he exibited marked isolated right superior rectus palsy which was also indicated by the Hess test. No other neurological abnormalities were found such as other ocular muscle paresis, cranial nerve palsies, hemiparesis, sensory impairement or cerebellar ataxia. MRI showed a left medial thalamic infarction extending to a rostral part of the midbrain anterolateral to the cerebral aqueduct at the superior colliculi level. Unilateral superior rectus palsy can rarely be caused by a contralateral midbrain infarction, because fibers from the subnucleus subserving the superior rectus decussate within the oculomoter nerve complex. In this case the crossing fibers toward the contralateral superior rectus may have been selectively involved by a tinny lesion in the area of the oculomotor nucleus. The patient had a slightly narrowed right palpebral fissure. It is indicated that crossing fibers toward the contralateral levator muscle of the eyelid may be also involved. The patient's diplopia completely resolved two months later after the onset.

(CLINICA NEUROL, 45: 445|448, 2005)
key words: diplopia, superior rectus palsy, crossed superior rectus palsy, midbrain infarction

(Received: 16-Aug-04)