SEARCH RESULTS FOR: Cranial-Nerve-IV-Palsy

Cranial Nerve IV Palsy

Cranial Nerve IV Palsy: Pathogenesis and clinical findings Congenital (e.g. Möbius Syndrome) Dysgenesis (defective development) of CN IV Microvascular Disease (e.g. Stroke) Damage or occlusion (complete or partial blockage) to the blood vessels supplying CN IV Trauma Temporary or permanent damage to the nerve fibers Neoplasm Metastasis (e.g. Leptomeningeal) Compression of the nerve fibers along the nerve tract Primary (e.g. Schwannoma) Tumor develops new blood vessels that redirect blood flow to the malignancy, away from the nerve Ischemia of CN IV Infection (a rare cause) (e.g. Ehrlichia chaffeensis, Tuberculosis meningitis) Infectious process in the subarachnoid space Damage to axons of CN IV Cranial Nerve (CN) IV Palsy Superior oblique musculature weakness due to CN IV dysfunction Lesion to the fascicle of CN IV (extending from midbrain to cavernous sinus) Impaired ability to conduct motor commands from nucleus to superior oblique muscle in the eye Weak superior oblique innervation Difficult abduction and intorsion of the eye Contralateral superior oblique weakness Lesion to the nucleus of CN IV (located in the midbrain) Disturbed signal production occurring prior to demarcation of fibers to contralateral side The pathophysiology above can cause damage to structures surrounding CN IV in the midbrain Impacting ipsilateral sympathetic chain descending from the hypothalamus prior to reaching the superior cervical ganglion Authors: Shahab Marzoughi Reviewers: Sunawer Aujla Yvette Ysabel Yao Yan Yu* Gary Michael Klein* * MD at time of publication Vertical/oblique Diplopia (double vision) Hypertropia (one eye is deviated upward compared to the other) Perinaud’s Syndrome (upgaze palsy, convergence retraction nystagmus, and pupillary hyporeflexia) See relevant Calgary Guide slide on Parinaud’s Syndrome Loss of eye muscle movement coordination and function of other structures relating to gait Ataxia Ipsilateral Primary Horner’s Syndrome (miosis, anhidrosis, ptosis) See relevant Calgary Guide slide on Horner Syndrome Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published January 16, 2024 on www.thecalgaryguide.com