Early diagnostic challenges of isolated ocular motor nerve palsy: diabetic, ischemic, or Tolosa-Hunt Syndrome.

Objective: Investigating the clinical features and etiological diagnosis of early isolated ocular motor nerve palsy to deepen understanding of the condition.

Methods: We retrospectively enrolled 68 patients with isolated ocular motor nerve palsy admitted our hospital between 2017 and 2024. A retrospective analysis was conducted to assess their clinical and imaging characteristics. Based on current diagnostic criteria, patients were categorized into one of the following groups: diabetic ophthalmoplegia (DO), microvascular ocular motor nerve palsies (MVP), or Tolosa-Hunt syndrome (THS). Patients were divided into two groups based on the presence of diabetes, and the clinical and imaging differences between the two groups were compared.

Results: Of the 68 patients, 40 were male, with an average age of 61 years. There were 43 patients with diabetes, and 40 had a history of hypertension. The number of patients with isolated 3rd, 4th, and 6th nerve palsy was 42, 15, and 11, respectively. Sixty patients experienced headache or orbital pain. 46 patients met the criteria for MVP. Among them, 31 patients had DO, and 15 non-diabetic patients also met the criteria for MVP. Of the 46 patients, 22 showed abnormalities on contrast-enhanced MRI. 19 patients were diagnosed with THS. In the diabetic and non-diabetic groups, 11 and 9 patients, respectively, were diagnosed with THS. The number of patients receiving steroid treatment in the diabetic and non-diabetic groups was 38 and 23, respectively, with pain relief rates within 3 days of 70 and 56%,  > 0.05.

Conclusion: Currently, the boundaries between DO, MVP, diabetes combined with THS, and benign THS remain unclear. There is a need for clinical research involving specialists in neurology, ophthalmology, and otolaryngology to establish standardized definitions, classifications, and diagnostic criteria.