Horizontal Gaze Palsy, Facial Nerve Palsy, and Nystagmus Due to Dorsal Pontine Ischemia

𝗢𝗿𝗶𝗴𝗶𝗻𝗮𝗹 𝗗𝗲𝘀𝗰𝗿𝗶𝗽𝘁𝗶𝗼𝗻: Presented here are two patients with horizontal gaze and facial palsies due to stroke. The first patient is a 60-year-old man who presented with double vision and hemiparesis due to a right dorsal pontine ischemic stroke. His exam was significant for a right horizontal gaze palsy due to right 6th nucleus involvement and right internuclear ophthalmoplegia (INO) (together, a one-and-a-half syndrome). There was also a right lower motor neuron facial palsy from a fascicular right 7th nerve palsy (also known as "eight-and-a-half syndrome" given the 7th + one-and-a-half syndrome). There was also upbeating nystagmus in upgaze due to involvement of the vertical gaze holding pathways. Convergence only improved adduction deficits mildly. The second patient is a 50-year-old man who presented with facial weakness and hemiparesis, in addition to oscillopsia due to a left dorsal pontine hemorrhage. He was unable to look left (with pursuit, saccades, or with the vestibular-ocular reflex), localizing to the left 6th nucleus; there was a left lower motor neuron facial palsy due to a fascicular 7th nerve palsy (together with the gaze palsy, an "eight syndrome"). There was also upbeat-torsional nystagmus towards the right ear, presumably due to involvement of the vertical semicircular canal pathways (mainly involving the anterior pathways given downward slow and upward fast phase). The anterior canal pathways travel through the superior conjunctivum, ventral tegmental tract, and medial longitudinal fasciculus (MLF), whereas the posterior canal pathways travel through the MLF only. Of note, in this patient's case, there was no clear INO to suggest MLF involvement. Convergence only improved his adduction deficit mildly. 𝗡𝗲𝘂𝗿𝗼-𝗼𝗽𝗵𝘁𝗵𝗮𝗹𝗺𝗼𝗹𝗼𝗴𝘆 𝗮𝗻𝗱 𝗡𝗲𝘂𝗿𝗼-𝗼𝘁𝗼𝗹𝗼𝗴𝘆 𝗧𝗲𝘅𝘁𝗯𝗼𝗼𝗸 𝗟𝗲𝗴𝗲𝗻𝗱: The first patient presented with double vision and hemiparesis due to a right pontine ischemic stroke. His exam was significant for a right horizontal gaze palsy due to right 6th nucleus involvement and right internuclear ophthalmoplegia (INO) (together, a one-and-a-half syndrome). There was also a right lower motor neuron (LMN) facial palsy from a fascicular right 7th NP (also known as "eight-and-a-half syndrome" given the 7th + one-and-a-half syndrome). There was also upbeating nystagmus in upgaze due to involvement of the vertical gaze holding pathways (possibly from the paramedian tracts). Convergence only improved adduction deficits mildly. The second patient presented with facial weakness, hemiparesis, and vertigo with oscillopsia due to a left dorsal pontine hemorrhage. He was unable to look left (with pursuit, saccades, or with the vestibular-ocular reflex), which localized to the left 6th nucleus; there was a left LMN 7th NP (together with the gaze palsy, an "eight syndrome"). There was also upbeat-torsional nystagmus towards the right ear, presumably due to involvement of the vertical semicircular canal pathways (mainly involving the anterior pathways given downward slow and upward fast phase). The anterior canal pathways travel through the superior conjunctivum, ventral tegmental tract, and medial longitudinal fasciculus (MLF), whereas the posterior canal pathways travel through the MLF only. Convergence only improved his adduction deficit mildly. https://collections.lib.utah.edu/ ark:/87278/s6g48ckf