Etiological and Prognostic Factors of Acquired Sixth Cranial Nerve Palsy

Introduction: CN6 palsy has been reported to be the most common ocular motor nerve palsy. It has vascular or ischemic and idiopathic etiologies. Its recovery rate is good compared to other ocular motor nerve palsies. Careful history taking and clinical evaluation are as important as imaging evaluation in CN6 palsy. Aim: This study aimed to determine etiology of sixth cranial nerve palsy and its effects on prognosis. Material and Methods: A hospital based prospective study was done on 52 patients who presented with acquired abducens nerve palsy at a tertiary care centre for a duration of 1 year. Results: Mean age was 47 years. Mean duration of recovery was 70 days. Vascular cause contributed to 50% cases, 21% were idiopathic, 17% were due to trauma and 12% were due to neoplasm. Rate of recovery was 79%. Neoplastic cases were least to recover. Conclusion: Most common cause of sixth cranial nerve palsy was vascular (46%), followed by idiopathic (21%), trauma (17%), neoplasm (12%) and other causes (4%). Prognosis was best for idiopathic and worst for neoplastic cause.