Cluster headache: further observations on the dissociation of pain and autonomic findings.

A 51-year-old male cluster headache patient had during five bouts in the course of 11 years always had the headache attacks on the left side. Autonomic abnormalities were, however, present on the right side. Pupillometrically, there was thus a Horner-like syndrome on the right (non-symptomatic) side, with miosis and a relatively more marked dilatation of that eye subsequent to topical application of a directly working sympathomimetic agent (phenylephrine) than after an indirectly working one (hydroxyamphetamine), whereas this was not the case on the symptomatic side. The findings on evaporimetry were not as clear-cut as the pupillometric findings; however, even facial sweating was consistent with a pathologic condition on the right (non-symptomatic) side. A primary dichotomy of pain and autonomic signs (that is, not due to change of side of pain localization) thus seems to be present in this case.