Peters GB 3rd, Bakri SJ, Krohel GB
Ophthalmology, November 2002 Journal Scan
Nontraumatic sixth nerve palsy (SNP) generally occurs in patients with vasculopathic risk factors (diabetes mellitus and hypertension) and in elderly patients. In general, isolated SNP in this group of patients does not require extensive investigation unless additional signs or symptoms develop or the ocular motility disturbance does not resolve within months after the onset of symptoms. In children, SNP may be caused by a virus or other inflammatory condition, which commonly resolves spontaneously. However, further evaluation is generally recommended in atypical cases, such as when sixth nerve palsy develops after adolescence and in middle-aged patients; further evaluation is necessary when SNP does not occur in isolation.
The authors of this retrospective, noncomparative case series reviewed the records of all patients 20 to 50 years of age with nontraumatic SNP, from 1994 to 2000. The results of neuroimaging, serology, and other tests to evaluate the etiology of the SNP were reviewed.
Altogether, 45 patients were included, 19 men and 26 women. Six patients had bilateral SNP. The causes included central nervous system (CNS) mass lesion (n = 15; 3 had isolated SNP and 12 had other signs and symptoms), multiple sclerosis (n = 11), idiopathic (n = 6), viral infection (n = 4), idiopathic intracranial hypertension (n = 3), meningitis (n = 3), microvascular (n = 2), and progressive spinocerebellar degeneration (n = 1).
In this study of younger patients, mass lesions of the CNS were the most common cause of nontraumatic SNP. However, when restricting the analysis to patients with isolated SNP, MS was the leading cause of the ocular misalignment. The results of this study support prior literature which suggests that younger patients with SNP should undergo a thorough evaluation, including neuroimaging, to uncover the cause of the ocular motility disorder.
© 2002 Medscape