Relationship between high prolactin levels and migraine attacks in patients with microprolactinoma.

The pathophysiology of pituitary-associated headache is unknown, although structural and functional features of the tumour are proposed mechanisms. The objective of this study was to evaluate whether headache in a population with pituitary micro-adenomas was related to hyperprolactinemia. We recruited 29 patients with microprolactinoma and headache: 16 with migraine (group A) and 13 with tension-type-headache (group B). The prolactin (PRL) levels measured during attacks of headache were significantly higher in nine patients (56%) of group A and in one patient (8%) of group B. In four of the nine patients of group A, PRL increased after thyrotropin-releasing-hormone (TRH) test and induced severe attacks. After dopamine-agonist (DA) treatment, the headache improved in seven (44%) patients of the group A and in two (15%) patients of the group B. Three of the four patients in whom the TRH-test induced headache attacks, improved after DA treatment. We suggest that hyperprolactinemia may contribute to development of pain in migraine subgroups and further TRH-test could be used to predict which patients could benefit by DA therapy.