A Hospital-Based Study on Aetiology of Third, Fourth and Sixth Cranial Nerve Palsies

Abstract

BACKGROUND Neuro-ophthalmology deals with complex systemic diseases that affect the visual system and pose a challenge for ophthalmologists. Here the focus is on the diseases of the nervous system that affect vision, ocular motility, or pupillary reflexes. Diplopia, a common symptom of cranial nerve palsy, may result from ophthalmic, orbital, or neurologic disorders. Our study intended to determine the aetiology of ocular motor nerve palsies. METHODS A cross-sectional study was conducted for two years at a tertiary care centre in South India. We evaluated 30 patients who came to the Ophthalmology OPD or were admitted, after obtaining the approval of the Ethics committee. RESULTS A total number of 30 patients who fulfilled the inclusion criteria were studied. There were 14 male and 16 female patients. The age range was 12 - 87 years with a mean age of 45 years. The highest incidence noticed was isolated sixth nerve palsy in 13 (43.3 %) patients. 11 patients had isolated third nerve palsy (36.7 %), while mixed ocular motor nerve palsies (third, fourth and sixth) were seen in 6 patients (20 %). None of them had isolated fourth nerve palsy. CONCLUSIONS  The sixth nerve continued to be the most common among the ocular motor nerve palsies. Meningitis was the major cause.  Diabetes and trauma, infections with CNS inflammation accounted for a majority of third nerve palsies.  Multiple cranial nerve palsies had varied aetiology like HIV Infection, Tolosa Hunt Syndrome, aneurysm of intracavernous part of ICA, cavernous sinus thrombosis and trauma.  The patient’s age, associated symptoms, clinical features and types of palsy are of great importance to choose appropriate radiological methods to study and treat these isolated cranial nerve palsies. KEY WORDS Diabetes, Meningitis, Oculomotor Nerve, Trochlear Nerve, Abducent Nerve, Trauma