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An Approach to Oculomotor Anomalies in a Child
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
Given the anatomy of the third nerve, there are several co-existent symptoms that should be sought on history and examination in order to localize the lesion and guide workup. Lesions of the oculomotor nucleus can result in bilateral ptosis (due to a shared LPS nucleus), contralateral or bilateral SR palsy (due to the crossing fibers of the SR nucleus), ipsilateral mydriasis and ipsilateral inferior rectus, medial rectus, and inferior oblique palsies. Although this clinical scenario is fairly classic for a nuclear lesion, there is variability in the possible presentation, and a nuclear third nerve palsy may also be mimicked by a fascicular lesion.11 Fascicular third nerve palsies are often associated with obvious neurological symptoms due to the adjacent structures in the brainstem. In children and adults with third nerve palsies, the following symptoms should be sought to evaluate for brainstem syndromes: contralateral ataxia (Claude syndrome), contralateral hemiparesis (Weber syndrome), and contralateral tremor (Benedikt syndrome). Despite the proximal location, fascicular third nerve palsies can present with superior or inferior divisional involvement given the topographical arrangement of the nerve fibers. Rarely, nuclear and fascicular lesions can result in an isolated muscle palsy, although isolated muscle palsies should also prompt consideration of other diagnostic entities.
Isolated Ocular Motor Nerve Palsies
Published in Journal of Binocular Vision and Ocular Motility, 2018
Stacy L. Pineles, Federico G. Velez
Given the anatomy of the third nerve, there are several coexistent symptoms that should be sought on history and examination in order to localize the lesion and guide work-up. Lesions of the oculomotor nucleus can result in bilateral ptosis (due to a shared LPS nucleus), contralateral or bilateral SR palsy (due to the crossing fibers of the SR nucleus), ipsilateral mydriasis and ipsilateral inferior rectus, medial rectus, and inferior oblique palsies. Although this clinical scenario is fairly classic for a nuclear lesion, there is variability in the possible presentation, and a nuclear third nerve palsy may also be mimicked by a fascicular lesion.11 Fascicular CNIII palsies are often associated with obvious neurological symptoms due to the adjacent structures in the brainstem. In children and adults with CNIII palsies, the following symptoms should be sought to evaluate for brainstem syndromes: contralateral ataxia (Claude syndrome), contralateral hemiparesis (Weber syndrome), and contralateral tremor (Benedikt syndrome). Despite the proximal location, fascicular CNIII palsies can present with superior or inferior divisional involvement given the topographical arrangement of the nerve fibers. Rarely, nuclear and fascicular lesions can result in an isolated muscle palsy, although isolated muscle palsies should also prompt consideration of other diagnostic entities.