A Misdiagnosis of Partial Oculomotor Nerve Palsy: A Curious Case of Stroke

The Oculomotor nerve (cranial nerve III) controls movement of four of the six extraocular muscles, the superior and inferior recti, the medial recti, the inferior oblique, and the levator palpebrae superioris. Lesions of the oculomotor nerve are rare. The resulting palsy can be bilateral or unilateral and complete or partial. The ophthalmologic findings are dependent on the etiology of the lesion and area of the nerve tract affected. We describe a 62-year-old African American woman who presented to the emergency department in hypertensive emergency with symptoms suggestive of abducens nerve (cranial nerve VI) palsy of the right eye. The magnetic resonance imaging (MRI) revealed acute pontine stroke involving an area of the left abducens nerve motor nucleus. However, the ophthalmologic examination demonstrated partial oculomotor nerve palsy. The objective of this case report is to remind the reader of the role of physical diagnosis rather than relying only on imaging in diagnosing partial oculomotor nerve palsy.