Pupillary disturbances in multiple sclerosis: correlation with MRI findings

Autonomic nervous system disturbances such as pupillary abnormalities have rarely been evaluated in multiple sclerosis (MS). However, pupillary impair ment is not uncommon in MS and its origin is still unclear. The aim of this study was to investigate pupillary disturbances in MS and to try to correl ate pupillary defects with spinal cord and brainstem magnetic resonance ima ging (MRI) findings. We prospectively studied 45 MS patients and 30 normal subjects. Methods: The pupillary contraction latency and the amplitude of c ontraction were recorded by pupillometry. We also determined afferent and e fferent pathway defects by comparing the direct and consensual pupillary re flexes. We evaluated brainstem and spinal cord demyelinating lesions and sp inal cord cross-sectional area on MRI. At least one pupillometric parameter s were significantly impaired in 60% of patients and in none of the control s. We did not find any correlation between pupillary defect and demyelinati ng lesions on MRI. The most frequent abnormality was efferent pathway shift and this was correlated with spinal cord atrophy (P < 0.02). These results confirm that the autonomic nervous system, and especially pupillary functi on., is frequently impaired in MS. The parasympathetic system is most commo nly affected and this is most likely linked to axonal loss (demonstrated by spinal cord atrophy) rather than to demyelinating lesions. (C) 2001 Elsevi er Science B.V. All rights reserved.