Radiologic Imaging in Third Nerve Palsy: A Case Series Investigating Etiology, Patterns, and Clinical Implications

Third nerve palsy (TNP) is a neurologic condition characterized by dysfunction of the oculomotor nerve, leading to various ocular manifestations. Optic nerve evaluation is of utmost important among all cranial nerve palsies affecting the eye. Dysfunction of the third nerve can indicate an underlying neurologic emergency, such as cavernous arteriovenous fistula or giant cell arteritis. Early recognition and prompt treatment are vital in reversing the clinical and visual impairments associated with oculomotor nerve palsy. The typical presentation of isolated TNP involves deviation of the eye in a downward and outward direction, accompanied by ptosis (drooping of the eyelid) and, potentially, pupil involvement. The decision to use vascular imaging is influenced by factors such as age and clinical risk for an aneurysm. If TNP is isolated or partially present with pupil involvement, it suggests compression of the third nerve and necessitates immediate imaging. Given the serious implications of an intracranial aneurysm, physicians often prioritize vascular imaging during the initial evaluation, if available. However, if clinical findings indicate underlying microvascular ischemia, a delay in imaging may be considered. This case series aims to explore the role of radiologic imaging in understanding the etiology, patterns, and clinical implications of TNP.