Convergence-Retraction Nystagmus in a Dog With Presumptive Ischemic Encephalopathy Following Acute Cervicothoracic Myelopathy

Liatis, Theophanes; Furtado, A. R. R.; Mantis, Panagiotis; Cherubini, Giunio Bruto

doi:10.1016/j.tcam.2019.100381

Cited by 2 publications

(1 citation statement)

References 49 publications

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“…2,3 In dogs, neuro-ophthalmological signs secondary to thalamic and midbrain ischemic infarcts have been reported rarely, and these signs include positional nystagmus, ipsilateral or contralateral positional ventral or ventrolateral strabismus, anisocoria with ipsilateral mydriasis, Horner syndrome and pupillary light reflex deficits, 4,5 whereas convergence-retraction nystagmus and Collier's sign can be manifested when the dorsal midbrain is affected. 6,7 To date, esotropia has been reported in dogs in association with ipsilateral abducens neuropathy, 8,9 extraocular myopathy 10 and congenital abnormalities, 11 but not secondary to thalamic lesions.…”

Section: Introductionmentioning

confidence: 99%

Medial strabismus (esotropia) at rest associated with contralateral paramedian thalamic ischemic infarction in 2 dogs

Liatis,

Plessas,

Volk

et al. 2024

Veterinary Internal Medicne

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Pseudoabducens paralysis resulting in resting medial strabismus (esotropia) is a rare consequence of a contralateral paramedian thalamic ischemic infarction in people. To date, esotropia has been reported in dogs in association with ipsilateral abducens neuropathy or extraocular myopathy, but not secondary to thalamic lesions. A 7‐year‐old male neutered Border Collie and a 12‐year‐old female neutered cross‐breed dog were presented with peracute nonprogressive vestibular ataxia. Neurological examination identified right esotropia, nonambulatory tetraparesis, right head tilt, vestibular ataxia and nystagmus. Lesions in both dogs were localized to the vestibular system with thalamic involvement. Magnetic resonance imaging of the brain identified a left paramedian thalamic lacunar ischemic infarct in both dogs. Interruption of descending inhibitory pathways that decussate in the subthalamic region and innervate the contralateral motor nucleus of the oculomotor nerve leads to hypertonicity of the medial rectus. These cases indicate that esotropia is a rare but highly localizing sign in dogs with contralateral thalamic infarcts.

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