Isolated Fourth Nerve Palsy in Nontraumatic Tentorial Hemorrhage

A 46-year-old woman being treated with warfarin for antiphospholipid antibody syndrome experienced a rise in international normalized ratio (INR) to 5.4 and developed sudden headache and diplopia. Neuro-ophthalmologic examination disclosed a right fourth nerve palsy. Noncontrast computed tomography revealed a subdural hematoma layered along the right tentorium cerebelli, directly in the path of the nerve. With normalization of the INR, the palsy markedly improved over subsequent weeks. This is a unique case of a nontraumatic subdural hematoma causing a fourth nerve palsy.

Photo Essay Section Editors: Melissa W. Ko, MD Dean M. Cestari, MD Isolated Fourth Nerve Palsy in Nontraumatic Tentorial Hemorrhage Eyal Walter, MD, Jonathan D. Trobe, MD FIG. 1. Precontrast brain computed tomography in the axial (A), sagittal (B), and coronal (C) projections shows high-density linear abnormality of the acute hemorrhage at the medial edge of right tentorium cerebelli. Abstract: A 46-year-old woman being treated with warfarin for antiphospholipid antibody syndrome experienced a rise in international normalized ratio (INR) to 5.4 and developed sudden headache and diplopia. Neuro-ophthalmologic examination disclosed a right fourth nerve palsy. Noncontrast computed tomography revealed a subdural hematoma layered along the right tentorium cerebelli, directly in the path of the nerve. With normalization of the INR, the palsy markedly improved over subsequent weeks. This is a unique case of a nontraumatic subdural hematoma causing a fourth nerve palsy. Journal of Neuro-Ophthalmology 2019;39:122-124 doi: 10.1097/WNO.0000000000000708 © 2018 by North American Neuro-Ophthalmology Society A 46-year-old woman was admitted for dilatation and curettage (D&C) and uterine ablation because of persistent vaginal bleeding. She had been placed on warfarin anticoagulation for tricuspid valve replacement, protein C and S Department of Ophthalmology and Visual Sciences (EW, JDT), Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan; and Department of Neurology (JDT), University of Michigan, Ann Arbor, Michigan. The authors report no conflicts of interest. Address correspondence to Jonathan D. Trobe, MD, University of Michigan, Ann Arbor, MI 48105; E-mail: [e-mail] 122 deficiency, systemic lupus erythematosus, antiphospholipid antibody syndrome, and previous deep vein thrombosis and pulmonary embolism. The international normalized ratio (INR) had been steadily maintained between 2.5 and 3.5. Before an uneventful D&C, she was administered 10 mg of vitamin K. After the procedure, she was restarted on warfarin, but the INR remained subtherapeutic for several days; so, the dose was increased. Seven days after the D&C, the INR was 5.4; so, the warfarin dose was lowered, but 2 days later, she experienced sudden headache, nausea, and vertical diplopia. Neuro-ophthalmologic examination showed an isolated right fourth nerve palsy. She denied head trauma. Noncontrast head computed tomography revealed a subdural hematoma (SDH) located along the right tentorium cerebelli (Fig. 1). It was attributed to the supratherapeutic INR. Examination 6 weeks later showed marked improvement in the fourth nerve palsy and regression of the tentorial hemorrhage (Fig. 2). SDH usually results from head trauma, but nontraumatic SDH is well documented, with coagulopathy accounting for 10% of all nontraumatic cases (1-4). As with traumatic SDH, the hemorrhage is usually located along the brain convexity (2,5). Our case is exceptional in being restricted to the tentorium cerebelli. As there was no head trauma in our patient, we presume that the fourth nerve palsy was caused by irritation or mass effect from the blood itself. After all, the hemorrhage Walter and Trobe: J Neuro-Ophthalmol 2019; 39: 122-124 Copyright © North American Neuro-Ophthalmology Society. Unauthorized reproduction of this article is prohibited. Photo Essay FIG. 2. Precontrast brain computed tomography performed 6 weeks after symptom onset shows regression of the tentorial hemorrhage. Images are shown in the axial (A), sagittal (B), and coronal (C) planes. FIG. 3. Schematic shows the relationship of the fourth nerve palsy to the tentorium cerebelli and the location of hemorrhage in our patient. in our patient lay directly in the path of the nerve (Fig. 3). We are unaware of previously reported cases of a spontaneous tentorial SDH leading to a fourth nerve palsy. There is a report of a unilateral third nerve palsy as an isolated neurologic abnormality in a patient who had suffered blunt head trauma and had a large ipsilateral tentorial edge hemorrhage (6). Although the authors attributed the third nerve palsy to the tentorial hemorrhage, the third nerve does not share the fourth nerve's intimate relationship to the tentorium (7). Thus, the third nerve palsy in that case could have resulted from contusion rather than the tentorial hemorrhage. Walter and Trobe: J Neuro-Ophthalmol 2019; 39: 122-124 STATEMENT OF AUTHORSHIP Category 1: a. Conception and design: E. Walter and J. D. Trobe; b. Acquisition of data: E. Walter and J. D. Trobe; c. Analysis and interpretation of data: E. Walter and J. D. Trobe. Category 2: a. Drafting the manuscript: E. Walter and J. D. Trobe; b. Revising it for intellectual content: E. Walter and J. D. Trobe. 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