Cluster-Like Headache Revealing Polycythemia Vera: A Case Report.

Herein, we report on a 44-year-old man who presented with cluster headache (CH)-like pain triggered by polycythemia vera (PV). He had severe unilateral head pain attacks lasting about 30 min not associated with cranial autonomic symptoms. After the exclusion of secondary etiologies, the patient was screened for a neoplastic process through biological markers, and the diagnosis of PV was established. The results of the initial laboratory examination showed hemoglobin at 18.1 g/L and Hct at 54%. JAK2 mutation analysis was positive at 54%, and marrow biopsy confirmed the hematopoietic clonal expansion, without myelofibrosis. He was treated with aspirin and ruxolitinib due to intolerance to interferon and the ineffectiveness of hydroxyurea. The treatment by venesection improved substantially the headaches. Oxygen inhalation was very effective in treating the CH attacks. In contrast, sumatriptan was inefficient at the very beginning of the disease. Among the pathophysiological mechanisms that we can propose to explain these cluster-like headaches are the prolonged hypoxia involving nitric oxide and calcitonin gene-related peptide release.