Daniel R. Gold, DO, Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, The Johns Hopkins School of Medicine
This is a 60-yo-man who presented with diplopia, headaches, and difficulty looking up, and was found to have a mass involving the pineal gland. Biopsy was diagnostic of a GBM. Major features of Parinaud's (dorsal midbrain) syndrome were present including: upgaze palsy, convergence retraction nystagmus, light-near dissociation, and skew deviation (not seen in the video). There was mild eyelid retraction as well. Lesions involving the posterior commissure (PC) mainly affect upward eye movements (PC doesn't carry fibers responsible for downward movements), and can cause vergence disorders, usually with an excess of convergence (may see pseudo-abducens). A skew deviation can result from utricle-ocular motor pathway injury as these fibers travel to the interstitial nucleus of Cajal (INC). The pupillary light reflex pathway can be affected as the result of damage to the pretectal nucleus or the fibers from pretectal nucleus to Edinger-Westphal (EW) nucleus. The pathways responsible for pupillary constriction during the near reflex do not travel through the pretectal nucleus, and synapse directly on EW. Because they are spared, light-near dissociation is the result.
Spencer S. Eccles Health Sciences Library, University of Utah