Cranial Neuropathy in Multiple Sclerosis

Abstract

OBJECTIVE: It has been reported that cranial neuropathy findings could be seen in the neurologic examination of multiple sclerosis (MS) patients, although brain magnetic resonance imaging (MRI) may not reveal any lesion responsible for the cranial nerve involvement. The aim of this study was to determine the frequency of brainstem and cranial nerve involvement, except for olfactory and optic nerves, during MS attacks, and to investigate the rate of an available explanation for the cranial neuropathy findings by lesion localization on brain MRI.

METHODS: Ninety-five attacks of 86 MS patients were included in the study. The patients underwent a complete neurological examination, and cranial nerve palsies (CNP) were determined during MS attacks.

RESULTS: CNP were found as follows: 3rd CNP in 7 (7.4%), 4th CNP in 1 (1.1%), 5th CNP in 6 (6.3%), 6th CNP in 12 (12.6%), 7th CNP in 5 (5.3%), 8th CNP in 4 (4.2%), and 9th and 10th CNP in 2 (2.1%) out of 95 attacks. Internuclear ophthalmoplegia (INO) was detected in 5 (5.4%), nystagmus in 37 (38.9%), vertigo in 9 (6.3%), and diplopia in 14 (14.7%) out of 95 attacks. Pons, mesencephalon and bulbus lesions were detected in 58.7%, 41.5% and 21.1% of the patients, respectively, on the brain MRI. Cranial nerve palsy findings could not be explained by the localization of the lesions on brainstem MRI in 5 attacks; 2 of them were 3rd CNP (1 with INO), 2 were 6th CNP and 1 was a combination of 6th, 7th and 8th CNP.

CONCLUSION: The most frequently affected cranial nerve and brainstem region in MS patients is the 6th cranial nerve and pons, respectively. A few of the MS patients have normal brainstem MRI, although they have cranial neuropathy findings in the neurologic examination.