The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders that are characterized by strictly unilateral trigeminal distribution pain occurring in association with ipsilateral cranial autonomic symptoms. This group includes cluster headache, paroxysmal hemicrania and short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing. These disorders are very painful, often considered to be some of the most painful conditions known to mankind, and consequently are highly disabling. They are distinguished by the frequency of attacks of pain, the length of the attacks and very characteristic responses to medical therapy, such that the diagnosis can usually be made clinically, which is important because it dictates therapy. The management of TACs can be very rewarding for physicians and highly beneficial to patients.

Evidence is emerging that migraine is not solely a headache disorder. Observations that ischemic stroke could occur in the setting of a migraine attack, and that migraine headaches could be precipitated by cerebral ischemia, initially highlighted a possibly association between migraine and cerebrovascular disease. More recently, large population-based studies that have demonstrated that migraineurs are at increased risk of stroke outside the setting of a migraine attack have prompted the concept that migraine and cerebrovascular disease are comorbid conditions. Explanations for this association are numerous and widely debated, particularly as the comorbid association does not appear to be confined to the cerebral circulation as cardiovascular and peripheral vascular disease also appear to be comorbid with migraine. A growing body of evidence has also suggested that migraineurs are more likely to be obese, hypertensive, hyperlipidemic and have impaired insulin sensitivity, all features of the metabolic syndrome. The comorbid association between migraine and cerebrovascular disease may consequently be explained by migraineurs having the metabolic syndrome and consequently being at increased risk of cerebrovascular disease. This review will summarise the salient evidence suggesting a comorbid association between migraine, cerebrovascular disease and the metabolic syndrome.

Introduction

The revised International Headache Society (IHS) criteria for cluster headache are: attacks of severe or very severe, strictly unilateral pain, which is orbital, supraorbital, or temporal pain, lasting 15 to 180 minutes and occurring from once every other day to eight times daily.

Methods and outcomes

We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to abort cluster headache? What are the effects of interventions to prevent cluster headache? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations, such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).

Results

We found 23 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.

Conclusions

In this systematic review, we present information relating to the effectiveness and safety of the following interventions: baclofen (oral); botulinum toxin (intramuscular); capsaicin (intranasal); chlorpromazine; civamide (intranasal); clonidine (transdermal); corticosteroids; ergotamine and dihydroergotamine (oral or intranasal); gabapentin (oral); greater occipital nerve injections (betamethasone plus xylocaine); high-dose and high-flow-rate oxygen; hyperbaric oxygen; leuprolide; lidocaine (intranasal); lithium (oral); melatonin; methysergide (oral); octreotide (subcutaneous); pizotifen (oral); sodium valproate (oral); sumatriptan (oral, subcutaneous, and intranasal); topiramate (oral); tricyclic antidepressants (TCAs); verapamil; and zolmitriptan (oral and intranasal).

Key Points

The revised International Headache Society (IHS) criteria for cluster headache are: attacks of severe or very severe, strictly unilateral pain, which is orbital, supraorbital, or temporal pain, lasting 15 to 180 minutes and occurring from once every other day to eight times daily. The attacks are associated with one or more of the following, all of which are ipsilateral: conjunctival injection, lacrimation, nasal congestion, rhinorrhoea, forehead and facial sweating, miosis, ptosis, and eyelid oedema. Most people are restless or agitated during an attack. Cluster headache may be episodic or chronic. Cluster headache is rare, but the exact prevalence remains a matter of debate.

The main focus of intervention is to abort attacks once they have begun and to prevent future attacks.

Sumatriptan, used subcutaneously or intranasally, and zolmitriptan used intranasally reduce the severity and duration of cluster headache attacks once they have begun. Oral zolmitriptan reduces severity of attacks in people with episodic cluster headache, but we don't know how effective it is in people with chronic cluster headache. We don't know whether oral sumatriptan is effective.

There is consensus that high-dose and high-flow-rate oxygen is effective for abortive treatment of episodic or chronic cluster headache. We don't know whether this consensus can be applied to hyperbaric oxygen, as little research has been conducted.

There is also consensus that subcutaneous octreotide is effective for abortive treatment of cluster headache.

We don't know whether intranasal lidocaine is effective for abortive treatment of cluster headache.

There is consensus that both verapamil and lithium prevent cluster headache, but that verapamil is more effective than lithium, and causes fewer adverse effects. There is also consensus that corticosteroids and greater occipital nerve injections (betamethasone plus xylocaine) are effective for preventive treatment.

We don't know whether baclofen, botulinum toxin, capsaicin, chlorpromazine, civamide, clonidine, ergotamine or dihydroergotamine, gabapentin, leuprolide, melatonin, methysergide, pizotifen, sodium valproate, oral sumatriptan, topiramate, or tricyclic antidepressants are effective for prevention of cluster headache. Some of these interventions are not routinely used in clinical practice.

Chronic daily headache is a major worldwide health problem that affects 3–5% of the population and results in substantial disability. Advances in the management of headache disorders have meant that a substantial proportion of patients can be effectively treated with medical treatments. However, a significant minority of these patients are intractable to conventional medical treatments. Occipital nerve stimulation (ONS) is emerging as a promising treatment for patients with medically intractable, highly disabling chronic headache disorders, including migraine, cluster headache and other less common headache syndromes. Open-label studies have suggested that this treatment modality is effective and recent controlled trial data are also encouraging. The procedure is performed using several technical variations that have been reviewed along with the complications, which are usually minor and tolerable. The mechanism of action is poorly understood, though recent data suggest that ONS could restore the balance within the impaired central pain system through slow neuromodulatory processes in the pain neuromatrix. While the available data are very encouraging, the ultimate confirmation of the utility of a new therapeutic modality should come from controlled trials before widespread use can be advocated; more controlled data are still needed to properly assess the role of ONS in the management of medically intractable headache disorders. Future studies also need to address the variables that are predictors of response, including clinical phenotypes, surgical techniques and stimulation parameters.