The role of neuroimaging in the evaluation process of children with isolated sixth nerve palsy

Purpose: The purpose of this study was to assess the role of neuroimaging in identifying the etiology of pediatric isolated sixth nerve palsy (SNP). Methods: A retrospective cohort study was conducted of all patients younger than 18 years of age with an isolated SNP seen at our medical center between 2003 and 2011. Results: Sixteen children (nine girls; mean age, 4.5 years) with isolated SNP were identified during an 8-year period. Only cases with normal optic disk appearance and otherwise normal neurological examination were included into this study. Thus, 12 other children with SNP were excluded: ten children with papilledema, one child who developed a SNP following a resection of a brain tumor, and one with hydrocephalus and a shunt malfunction. All cases of isolated SNP were unilateral (ten left eyes). The most common cause for the SNP in these children was a tumor that was found in five patients. Other etiologies encountered in decreasing frequencies were: benign recurrent SNP (in four children), postviral or vaccination (in three children), and one case each of post trauma, Chiari malformation, congenital, and undetermined. Children who were found to have a tumor (9.9 ± 5.5 years) were significantly older (P = 0.019) than children who did not have a tumor (2.1 ± 1.8 years). Conclusions: Isolated SNP can be the presentation of a brain tumor in children, and therefore, early neuroimaging of the brain is recommended, especially in older children.