Diagnosing and treating cluster headaches

Cluster headaches are the most common of the trigeminal autonomic cephalalgias as defined by the International Headache Society in the International Classification of Headache Disorders (ICHD), 3^rd edition.

Cluster headache pain is severe and disabling, so these headaches can result in significant morbidity. On the other hand, they are quite manageable, once recognized.

Cluster headaches are cyclical, episodic headaches which are associated with autonomic nervous system phenomena of the cranium. They have very distinct characteristics including their pain character and pattern, associated autonomic features, and timing.

Pain characteristics of cluster headaches

The pain is severe, often described as boring, searing, or burning, sometimes like a hot poker in the eye.

It is unilateral, orbital / periorbital (including supraorbital), and may or may not include temporal pain. While the pain is centered around the eye, it can radiate, thus causing confusion with secondary conditions such as dental disease, cranial neuralgias, or sinus disease.

Autonomic features associated with cluster headaches

Cluster headaches always include at least one of the following autonomic symptoms or signs, ipsilateral to the headache:

• Conjunctival injection and / or lacrimation
• Eyelid edema
• Nasal congestion and / or rhinorrhea
• Forehead and facial sweating
• Miosis and / or ptosis
• A sense of restlessness or agitation

The temporal pattern of cluster headaches

Cluster headaches must have produced at least five attacks to be properly diagnosed. Attacks occur from 15 minutes to three hours at a time, with a frequency of one headache every other day, up to eight headaches per day.

As the name implies, the attacks occur in clusters. The series of attacks may last weeks to months. Clusters are separated by periods of remission which can last months to years. Often, bouts occur seasonally, and the cluster may last six to 12 weeks.

Most patients report the cycles of recurrent cluster bouts occurring on the same side. However, the side might change with each new cluster cycle.

Episodic and chronic subtypes of cluster headaches

Cluster headaches are divided into episodic and chronic forms based on the frequency of bouts.

Episodic cluster headaches

Episodic cluster headaches occur periodically, with bouts recurrent over seven days to a year, punctuated by pain-free periods lasting at least three months.

Chronic cluster headaches

Chronic cluster headaches occur for periods of a year or more with no pain-free periods, or pain-free periods of less than three months.

Cluster headaches occur four times more frequently in men than in women. Age of onset can be variable, but typically cluster headaches appear in early adulthood. There is also a familial subtype of cluster headache.

Episodes of cluster headache can be treated with subcutaneous injections of Sumatriptan or inhalation of 100% oxygen. Dihydroergotamine nasal spray and intravenous therapy (IV) can be used as well. Intranasal Sumatriptan, Zolmitriptan, or Lidocaine have been used with less efficacy.

Clusters can also be aborted with tapered oral steroids over ten or more days.

Prevention is possible using Verapamil, Lithium, Topiramate, or Valproate.