Third Nerve Palsy Due to Tolosa Hunt Syndrome

This is a 20-year-old woman presenting with severe left eye pain and diplopia for several days. Examination was consistent with a pupil sparing left 3rd nerve palsy with complete external ophthalmoplegia (involving levator palpebrae, medial rectus, superior rectus, inferior rectus). Abduction OS was normal, and with attempted downgaze, mild incycloduction OS was apparent; therefore, while a mild left 4th nerve palsy could not be excluded, at least partial function of the left 4th nerve was demonstrated (i.e., primary action of the 4th nerve/superior oblique muscle is incycloduction). There was also reduced sensation in the distribution of V1 and V2 nerves on the left face. Afferent examination was normal and other cranial nerves were uninvolved. Contrast-enhanced MRI demonstrated enhancement within the left cavernous sinus. CSF analysis was normal. She was treated with steroids, and the pain and 3rd nerve palsy improved significantly over days. A presumptive diagnosis of Tolosa Hunt syndrome was made, and the patient did not follow-up. The differential diagnosis of painful ophthalmoplegia mainly includes Tolosa Hunt syndrome, ophthalmoplegic migraine, diabetic ophthalmoplegia, aneurysmal, cavernous sinus thrombosis, dural arteriovenous fistula, meningioma, neurilemmoma, nasopharyngeal carcinoma, pituitary adenoma, metastatic tumor, or fungal infection. None of these other etiologies seemed likely or were excluded with neuroimaging, CSF analysis, and blood work. Tolosa Hunt syndrome should be a diagnosis of exclusion, and the clinician should be aware of mimics such as infection or neoplasm (e.g., lymphoma). Patients should be followed closely over time.