Horner's syndrome and thalamic lesions: Report of two cases

Abstract

The authors report two cases with Horner's syndrome and thalamic lesions documented by CT and MRI. There is evidence of a right posterolateral thalamic hemorrhage in one case and a left anterior thalamic infarction in the other. The possible mechanisms of sympathetic pathway involvement in these cases are discussed. In the first case, Horner's syndrome could be due to compression of the posterior hypothalamic area-where the sympathetic pathway's superior center is supposed to be located-or of the posterior longitudinal fasciculus, by edema resulting from the hemorrhage. In the second case, there is evidence of a small infarction, which appears to be limited to the tuberothalamic territory. In this case, the authors postulate a possible role of the thalamus in the development of a Horner's syndrome, perhaps by way of thalamic projections to the hypothalamic sympathetic center.

Key Words:

• Horner's syndrome
• thalamus
• sympathetic pathways