Diagnosis and treatment of cluster headache.

Cluster headache is an uncommon yet distinctive neurovascular syndrome occurring in either episodic or chronic patterns. The most unique feature of cluster headache is the unmistakable circadian and circannual periodicity. The attacks are stereotypical, that is, of extreme intensity, of short duration, occurring unilaterally, and associated with robust signs and symptoms of autonomic dysfunction. Unlike migraine, during an attack the patient with cluster headache often paces about. Attacks frequently occur at night, awakening the patient from sleep. Although the pathophysiology of cluster headache remains to be fully elucidated, several seminal observations have recently been made. The medical treatment of cluster headache includes acute, transitional, and maintenance prophylaxis. Agents used for acute therapy include inhalation of oxygen and triptans, such as sumatriptan, and dihydroergotamine. Transitional prophylaxis refers to the short-term use of fast-acting agents. This typically involves either corticosteroids or ergotamine derivatives. The mainstay of prophylactic therapy is verapamil. Lithium, divalproex sodium, or topiramate may also be useful. As the sophistication of functional neuroimaging increases, so too will our ability to better understand the anatomic and metabolic perturbations that underlie cluster headache.