[Treatment of cluster headache].

INTRODUCTION

The cluster headache (CH) is one of the most severe types of head pain. It is a typical example of a periodic disease and the International Headache Society classification recognizes two forms of this disease: episodic and chronic CH. Its prevalence is about 0.1 to 0.4% in the general population.

PATHOPHYSIOLOGY

A global hypothesis is still lacking to explain the pain, the vasodilation, the autonomic features (ipsilateral lacrimation, conjunctiva injection, rhinorrhea, partial Horner syndrome, etc.) and the periodicity of the CH. Pain and vasodilation seem secondary to an activation of the trigeminal vascular system and the periodicity of the attacks is thought to be due to a dysfunction of hypothalamic biologic clock mechanisms. Treatment of acute CH attacks. The most effective agents are oxygen inhalation and subcutaneous sumatriptan, a 5HT1B and D receptor agonist which has vasoconstrictor and anti-neurogenic inflammation properties by blocking the release from the trigeminal-sensitive fibers of neuropeptides such as CGRP and substance P. With subcutaneous sumatriptan, headache relief is very rapid, within 5 to 10 min. Prophylactic treatment of CH: The number of attacks per day varies from one to three, but some patients can have four to eight per day and acute treatments fail to provide sufficient relief or give rise to side-effects. Several different regimens have been proven effective.

FUTURE PROSPECTS AND PROJECTS

Contraindications and side-effects of the drugs limit the choice of the prophylactic treatment: corticosteroids in a tapering course, verapamil and methysergide are the most useful treatments of the episodic form. Lithium carbonate is more effective for the chronic stage of CH, but side-effects are often troublesome. Numerous other medications have been used for prophylaxis: valproate, capsaicin, beta-blockers. Unfortunately, double-blind studies are often lacking and are difficult to realize due to spontaneous variable remission of episodic CH. When adequate trials of drug therapies show a total resistance to the treatments, surgery may be considered. Radiofrequency trigeminal rhizotomy is the treatment of choice with 70% of beneficial effects. Risks and complications have to be discussed in balance with the benefit of the different surgical procedures.