Majority of isolated fourth nerve palsies are congenital
FEB 14, 2018
Neuro-Ophthalmology/Orbit
This population-based study evaluated the incidence and etiology of isolated, presumed fourth nerve palsy. Study design The authors used a database of Olmsted County, Minnesota, residents to identify all cases of isolated fourth nerve palsy diagnosed over a 15-year period. Outcomes Seventy-three patients were identified; mean age at presentation was 41.8 years. After adjustment for age and sex, the annual incidence rate was 5.73 per 100,000 per year, with a higher incidence in males than females. The most common etiology was presumed congenital (49%), followed by hypertension (18%) and trauma (18%). One patient (1%) had fourth nerve palsy owing to a known intracranial neoplasm. The cause was undetermined for 3 patients (4%). The most common decade of presentation was the fourth decade, including for presumed congenital cases. Limitations The population studied was predominately white. Thus, the results may be different for a...