Copyright 2017 The Korean Society of Neuro-Ophthalmology http://neuro-ophthalmology.co.kr S45 ISSN: 2234-0971
An Unusual Cause of Unilateral Sixth Nerve Palsy
Seoi-yeol Rhu, Bong-hui Kang, Jae-il Kim
Department of Neurology, Dankook University Medical College, Cheonan, Korea
Background: Cranial nerve six (CN VI), the abducens nerve, is to innervate the lateral rectus muscle. A lesion anywhere along the CN VI course, from the pons to the orbit, can cause a paresis or palsy. Causes of isolated sixth nerve palsy is usually considered dia- betes mellitus, hypertension or a recent viral infection. Herein we discuss an unusual case of sixth nerve palsy.
Case report: A 46 year-old man presented to our hospital complaining of headache, nausea and vomiting for the previous a week.
He had noticed blurred vision at the same time. He did not have any previous health problem in the past except multiple fractures in the right distal leg caused by car accident 10 months ago. In physical exam, vital signs showed high blood pressures and normal body temperatures. His neurological examinations showed definite neck stiffness and incomplete abduction of the right eye com- plaining of horizontal binocular diplopia. Mild hypoosmolar hyponatremia was observed in his first laboratory tests, maybe caused by vomiting. The initial brain CT was normal. In cerebrospinal fluid analysis, the pressure was high, 31 cmH
2O, RBC 19/mm
3, WBC 0 / mm
3, protein 16.9 mg/dL and glucose 67 mg/dL. His Brain MRI showed iso-signal intensities in T2WI and dark signal in GRE filling in- ternal jugular vein, superior sagittal, right sigmoid and transverse sinuses, and empty delta signs in post-enhanced T1WI. Papill- edema on fundoscopy was not observed. He was diagnosed with cerebral venous sinus thrombosis (CVST) and treated with intra- venous heparin and mannitol. He was getting better in a few days. On the 11th day after admission, he was discharged with mild blurred vision in nearly full lateral gaze to the right. At the first follow-up in outpatient clinic, he had no symptom and no focal neu- rologic deficit.
Conclusion: Clinical presentation of CVST is varied and often mimics many neurological disorders, making it a diagnostic chal- lenge, and cranial nerve palsy in CVST is rare and its pathophysiology remains unclear. Sixth nerve palsy as an isolated manifesta- tion of CVST has been attributed to the elevated intracranial pressure, extension of thrombosis to venous channels or direct com- pression from the clot itself in the inferior petrosal sinus.
대한안신경의학회지: 제7권 Supplement 1 Clin Neuroophthalmol 7(Suppl 1):S45-45, May 2017
