The incidence and etiology of sixth cranial nerve palsy in Koreans: A 10-year nationwide cohort study.

We aimed to investigate the incidence, prevalence, and etiology of sixth cranial nerve (CN6) palsy in the general Korean population. The nationally representative dataset of the Korea National Health Insurance Service-National Sample Cohort from 2006 through 2015 was analyzed. The incidence and prevalence of CN6 palsy were estimated in the cohort population, confirming that incident cases of CN6 palsy involved a preceding disease-free period of ≥4 years. The etiologies of CN6 palsy were presumed using comorbidity conditions. Among the 1,108,256 cohort subjects, CN6 palsy developed in 486 patients during the 10-year follow-up. The overall incidence of CN6 palsy was estimated to be 4.66 per 100,000 person-years (95% confidence interval [CI], 4.26-5.08) in the general population. This incidence increased with age, accelerating after 60 years of age and peaking at 70-74 years of age. The mean male-to-female incidence ratio was estimated as 1.41 in the whole population, and the incidence and prevalence of CN6 palsy showed an increasing trend over time in the study period. Surgical incidence for CN6 palsy was only 0.19 per 100,000 person-years (95% CI, 0.12-0.29). The etiologies were presumed to be vascular (56.6%), idiopathic (27.2%), neoplastic (5.6%), and traumatic (4.9%). In conclusion, the incidence of CN6 palsy increases with age, peaking at around 70 years, and shows a mild male predominance in Koreans.

Neurocysticercosis presenting as a vertical one-and-a-half syndrome with associated contralesional horizontal gaze paresis.

We describe a patient presenting with vertical one-and-a-half syndrome and concomitant contralesional horizontal gaze paresis as the result of a solitary neurocysticercosis (NCC) lesion in the right midbrain extending into the thalamomesencephalic junction. The patient received an albendazole-dexamethasone course which resulted in resolution of his symptoms. The neuro-ophthalmological complications of NCC are reviewed and the clinical topography of the neuro-ophthalmological findings of this unusual observation are discussed.

Sudden death from pituitary apoplexy in a patient presenting with an isolated sixth cranial nerve palsy.

A 68-year-old diabetic, hypertensive man presented with a left sixth cranial nerve palsy. MRI demonstrated an inhomogeneous sellar mass encroaching on the left cavernous sinus. Two days later, a left third cranial nerve palsy developed. Within 24 hours, the patient went into cardiac arrest and died. An autopsy showed hemorrhage within a pituitary macroadenoma ("pituitary apoplexy"). Pituitary apoplexy should be considered a cause of acute isolated sixth cranial nerve palsy and may represent a life-threatening emergency that can be averted with emergent hormonal replacement and hypophysectomy.