A Prospective Study of the Causes and Magnetic Resonance Imaging Findings in Adult Isolated Non-traumatic Unilateral Abducens Palsy in Taiwan

Abstract

The objective of this study was to investigate the causes of acute isolated non-traumatic unilateral abducens palsy in adults and to evaluate the diagnostic relevance of Magnetic Resonance Imaging (MRI). This prospective study included a total of 40 patients presenting with acute isolated unilateral non-traumatic abducens palsy from January 2002 to June 2008 at Buddhst Tzu Chi General Hospital, Hualien. A standardized MRI protocol was performed within 1 week of the patient's first visit. In 23 patients (57.5%) a lesion was identified on the initial MRI relevant to the sixth nerve palsy. In 8 patients (20%) the cause was nasopharyngeal carcinoma. The MRI was positive in 4 out of 15 diabetic patients, and in 5 out of 12 patients with hypertension. MRI demonstrated the aetiology in 57.5% of cases of acute isolated non-traumatic unilateral abducens palsy, with nasopharyngeal carcinoma being a common cause in our study. We suggest a complete MRI study of the brain and the orbits, with axial, coronal and sagittal imaging, the use of intravenous contrast, and fat suppression techniques in acute adult isolated non-traumatic unilateral abducens palsy.

Keywords:

• abducens nerve palsy
• sixth nerve palsy
• nasopharyngeal carcinoma