Objective:

NA

Background:

Pseudo-abducens palsy is a limitation of ocular abduction that mimics an abducens palsy in the absence of a lesion affecting the abducens nerve.

Design/Methods:

NA

Results:

An 87-year-old female with type 2 diabetes and hypertension presented with weakness, diplopia, and blurry vision. The examination showed limited left eye abduction with esotropia, mild hypophonic dysarthria, and mild left-sided weakness with left lower quadrant facial drooping. Brain MRI showed focal diffusion restriction in the medial right thalamus with T2 Fluid Attenuated Inversion Recovery (FLAIR) mismatch. She received tenecteplase (TNK) before transfer to the neurocritical care unit, where she showed clinical improvement but had persistent left lower facial drooping and difficulty with left eye abduction. Brain MRI 24 hours after TNK showed the same diffusion restriction in the right thalamus with corresponding T2 FLAIR hyperintensity. The etiology of her stroke was attributed to small vessel disease. Her diplopia improved but would fluctuate. The patient was initiated on dual antiplatelet therapy with aspirin and clopidogrel for 21 days, as well as a high-intensity statin.

Conclusions:

This case highlights a rare ocular presentation of thalamic stroke. Pseudo-abducens palsy arises from supranuclear lesions, predominantly from lacunar infarcts of the thalamo-mesencephalic junction, rostral midbrain, or rostral pons. The distinguishing clinical feature from abducens palsy is impaired voluntary abduction with preserved abduction on vestibulo-ocular reflex testing. The contralateral abduction restriction likely stems from disrupted descending inhibitory pathways that cross the paramedian thalamus and decussate in the subthalamic region to reach the contralateral third oculomotor nucleus, causing contralateral tonic medial rectus activation and esotropia. While pseudo-abducens palsy is considered rare and likely underreported, increased recognition by incorporating clinical localization skills can facilitate accurate diagnosis and management.