Dexamethasone suppression test, melatonin and TRH-test in cluster headache.

The origin of Cluster Headache (CH) is still unknown. The periodicty and presence of symptoms due to both sympathetic and parasympathetic activity suggest the involvement of central nervous system structures, particularly the hypothalamus. To investigate hypothalamic involvement in CH, we employed a neuroendocrinological approach. We observed a normal dexamethasone suppression test (DST) in all patients, increased cortisol plasma levels in remission patients at 8.00am before and at the end of the DST, while only in CH patients during cluster period did we find a reduced TSH response to TRH and a reduced night-time melatonin peak. The neuroendocrinological derangements found in CH may be consistent with hypothalamic involvement.