Harlequin syndrome: does a cranial autonomic neuropathy influence headache?

Drummond, P.D. and Lance, J. W. (2012) Harlequin syndrome: does a cranial autonomic neuropathy influence headache? Journal of Neurology, Neurosurgery & Psychiatry, 83 (6). p. 577.

Abstract

The paper by Viana et al analyses the relationship between Harlequin syndrome and headache. One facet of this interesting syndrome is the demonstration of pupillary signs by pharmacological studies explicable by the sudden onset of parasympathetic and sympathetic deficit, implicating an autonomic neuropathy mediated by an autoimmune process or viral infection.