Upbeat nystagmus and internuclear ophthalmoplegia with brainstem glioma
B. T. Troost, J. Martinez, L. A. Abel and R. C. Heros
We describe the unusual association of two ocular motor abnormalities:
upbeat nystagmus and internuclear ophthalmoplegia in a young woman
originally believed to have demyelinating disease. Quantitative eye
movement recordings documented a unidirectional defect in upward visual
pursuit with preservation of the vertical vestibulo-ocular reflexes. The
ocular oscillation was characterized as a type of "pursuit defect"
nystagmus. An enhancing lesion of the upper brainstem seen on computerized
tomography was primarily localized to the midbrain on
pneumoencephalography. Biosy of the lesion disclosed a malignant glial
tumor. The patient's course initally progressed but became stable following
radiotherapy and chemotherapy during the next eight months. We believe the
association of upbeat nystagmus and internuclear ophthalmoglegia should
prompt a detailed search for a structural lesion.
