Two sisters with cluster headache were studied with respect to the pupillary responses to instillation into the conjunctival sac of a single drop of a 1% solution of phenylephrine and a 2% solution of tyramine. The changes in pupillary diameters were documented by photographic pupillometry prior to and at 15, 30, 60, and 90 minutes after the instillations.Of the two sisters, one (case A) was examined during a symptom-free interval, when she had been free from cluster headache attacks for 2 1/2 years. When the cluster headaches recurred, retesting was performed. The other sister (case B) had been free from cluster headaches for 9 years, when she was examined.The findings indicate hypofunction within the postganglionic sympathetic nerve fibers during a cluster headache period. The hypofunction is bilateral, and thus, can not be a consequence of the unilateral cluster headache attacks. During remissions, tyramine induces a marked mydriasis, particularly on the symptomatic side, tentatively indicating an excessive release of stored monoamines.Key words: cluster headache, pupil, phenylephrine, tyramine, sympathetic dysfunction Abbreviations: CH cluster headache (Headache 1996;36:448-451 ) The pathophysiology of cluster headache (CH) is unknown. Its prevalence is low, estimated at about 70 per 100000, 1 with a marked male preponderance. It is usually not considered a familial disorder, 2 though such cases have been reported. 2-6 A positive family history of CH is encountered in approximately 3% of sufferers, 7 the overwhelming majority being males.We recently had the opportunity to examine two sisters who had suffered from typical episodic CH fulfilling the diagnostic criteria of the International Headache Society (IHS). 8 One of the sisters gave a history of more or less regularly recurrent CH periods for more than 20 years. The other had been free from CH attacks for the previous 9 years. As a cephalic sympathetic dysfunction has been implicated in the pathophysiology of CH, 9-13 the two sisters were studied with respect to the pupillary responses to conjunctival instillation of phenylephrine and tyramine.
CASE HISTORIESCase A.-A 43-year-old woman sought medical advice because of recurrent periods of left-sided headache, localized around the eye. She had suffered from such a headache for more than 20 years. The periods were said to last for about 4 weeks and occurred annually, or at least every second year. The attacks had a duration of about 1 to 2 hours and used to occur particularly during nighttime. The headache was very intense and of a nonpulsating type. On rare occasions, she felt nauseated and vomited. During an attack, her left eye was red and tearing, and her ipsilateral nostril exhibited rhinorrhea, without being blocked.Between the headache periods, she was free from neurological symptoms. Her somatic and neurological examinations were normal. In particular, there was no anisocoria, nor any other manifestation of a partial Horner's syndrome. She had a gratifying response to prophylactic pizotifen (San...