Clinical and Etiological Spectrum of Third, Fourth, Sixth, and Seventh Cranial Nerve Palsies: A Hospital-Based Cross-Sectional Study

TL;DR

This study examines the causes and types of cranial nerve palsies affecting vision and facial movement in patients at a hospital in central India.

Contribution

The study provides a detailed clinical and etiological analysis of third, fourth, sixth, and seventh cranial nerve palsies in a specific geographic region.

Findings

Isolated seventh cranial nerve palsy was most common, affecting 40% of patients.

Sixth cranial nerve palsy was the second most frequent, primarily due to trauma-induced raised intracranial tension.

Cavernous sinus thrombosis was the main cause of multiple cranial nerve palsies.

Abstract

Purpose: Impairment of the third, fourth, sixth, and seventh cranial nerves can lead to neuro-ophthalmic symptoms that severely affect visual function and quality of life. This study aimed to evaluate the clinical profile, etiological spectrum, and anatomical localization of ocular cranial nerve palsies involving the third, fourth, sixth, and seventh cranial nerves in patients presenting to a tertiary healthcare center in central India.

Materials and methods: This 12-month cross-sectional observational study involved 30 patients presenting with diplopia, headache, facial asymmetry, or restricted ocular movements. Patients aged 18 years or older diagnosed with palsy of the third, fourth, sixth, or seventh cranial nerve were included. A detailed history, neuro-ophthalmic examination, and imaging (CT or MRI) were performed. Data analysis was conducted using descriptive statistics, with categorical variables expressed as frequencies and percentages and continuous variables summarized as means and standard deviations.

Results: A total of 30 patients meeting the inclusion criteria were studied. Isolated seventh cranial nerve palsy was the most common, occurring in 12 patients (40%), which caused facial weakness and lagophthalmos. It was followed by isolated sixth cranial nerve palsy in 10 patients (33.3%), which led to diplopia and headache. Isolated third cranial nerve palsy was noted in five cases (16.7%). Mixed motor nerve palsies involving the third, fourth, sixth, and seventh cranial nerves were seen in three cases (10%). Notably, no patients presented with isolated trochlear (fourth nerve) palsy. Bell’s palsy, trauma, and diabetes were the leading causes.

Conclusions: Seventh cranial nerve palsy was the most common, with Bell’s palsy as the leading cause. Sixth cranial nerve palsy, primarily due to trauma-induced raised intracranial tension, was the second most frequent. Third cranial nerve palsy was mostly linked to diabetes, while cavernous sinus thrombosis was the main cause of multiple cranial nerve palsies. Larger studies are necessary to further validate these findings.