Isolated Third Cranial Nerve Palsy: Aetiology - Clinical Profile and Recovery at a Tertiary Neuro-ophthalmology Centre on the East Coast Peninsular of Malaysia

Abstract

Objective: This study aimed to study the aetiologies, clinical profile and recovery of isolated third cranial nerve palsy (ITCNP) patients, at a tertiary neuro-ophthalmology center on the East Coast Peninsular of Malaysia. Material and Methods: This was a retrospective study, involving 33 patients with newly diagnosed ITCNP, who were treated at the Hospital of the Universiti Sains, Malaysia; from January 2018 to December 2019, with a follow up period ranging from 18 to 24 months. The demographic data, clinical features and aetiologies of the patients were analysed. Results: Patients’ ages ranged from 14 to 79 years (mean: 48, 50 years of age). The main aetiology was microvascular ischemia (39.4%), followed by trauma (30.3%), aneurysm (15.2%), tumour (9.1%) and undetermined cause (6.1%). Neuroimaging was performed for those indicated cases; with either computed tomography (CT), CT angiography, digital subtraction angiography, magnetic resonance imaging (MRI) with contrast or MRI angiography. Two-thirds of the patients (66.7%) had periorbital pain, which included 30.8% of patients with microvascular ischemia and 60.6% had pupil involvement; which was also found in 23.1% of patients with microvascular ischemia. Complete external third nerve palsy occurred in 18.2% of patients, and aberrant regeneration was observed in 36.4% of patients. Complete recovery occurred in 48.5%, of all patients, having microvascular ischemia and undetermined causes. Conclusion: The aetiologies, clinical profile and recovery of ITCNP patients in our institution are comparable to those reported in other previous studies. Patients with microvascular ischemia may also demonstrate periorbital pain and anisocoria. Neuroimaging remains the gold standard and the best tool via which to exclude other sinister and lifethreatening aetiologies.