The need for more research into cluster headache

The excruciating pain of cluster headache underlies its "suicide headache" label, but more research is needed to understand its underlying circadian mechanism.In a review of the pathogenesis, diagnosis and treatment of cluster headache, Dr Arne May from Hamburg says that the syndrome has been clinically well-defined, but its pathophysiology is still poorly understood. The vascular theory has been superseded with the recognition of the importance of neurovascular factors and some central impulse generator. However, the author says, "Any pathophysiological model needs to explain the three major features of cluster headache: trigeminal distribution of the pain, ipsilateral cranial autonomic features, and (circadian) episodic pattern of attacks." The hypothalamus is a key region in the pathophysiological process, and the author suggests, "It is probably better to regard the condition as a hypothalamic syndrome rather than as a simple headache". This description takes into account hypothalamic symptoms such as aggressiveness, sleep disturbance, restlessness, and endocrine and vegetative symptoms typically encountered in many patients.Effective prophylactic therapy is needed to avoid overmedication and toxicity from repeated treatment of acute attacks. Verapamil remains first-line preventive therapy, but there is also data on the use of lithium, methysergide and corticosteroids.Cluster periods are refractory to normal preventive treatment or develop resistance in 10-20% of patients, and third-line therapies may be required. Pizotifen, capsaicin, and baclofen have limited data to support their use. Surgery may also have a role, but the author points out, "In general, any surgical procedure on peripheral trigeminal structures in episodic cluster headache must be judged with great caution, as the nature of the disorder is to remit."Cluster headache is much less common than migraine. As a result, most headache funding has been directed towards migraine, which has led to highly specific treatment and a good understanding of the underlying processes. Dr May believes more research is required into cluster headache to not only improve treatment for sufferers, but to also "help to unravel the physiological interaction between the internal biological clock and pain perception and control."Reference...