Migraine is the most common neurological condition encountered by GPs - affecting about 12% of the adult population; 17% of women and 6% of men. Diagnosis is based on a well-recognised constellation of symptoms. Patients typically report discrete attacks of moderate to severe, often unilateral headache, accompanied by nausea, sometimes vomiting and photophobia or phonophobia. Attacks are separated by symptom-free intervals.1 After several years of episodic attacks, migraine may become chronic because of biochemical factors or overuse of pain-relieving medications. According to the International Headache Society, the diagnostic features of chronic migraine are headaches occurring on 15 or more days per month, of which eight days or more are with migraine.2 Chronic migraine is more severe and more difficult to treat than episodic migraine.
History and investigations
When your patient presents with chronic migraine there are a number of questions you should ask:
Is any original diagnosis of migraine correct?
Any existing diagnosis of migraine should be reviewed if there is any change in headache characteristics. If there is any doubt about the diagnosis, the patient should be referred to A&E or to the local on-call neurology service. In most cases there will be no sinister pathology and a diagnosis of migraine will be confirmed.
Is the diagnosis chronic migraine?
Once a history of migraine is confirmed, give the patient a headache diary to record their headaches, treatments taken and their efficacy. Several suitable diaries are available, and a validated one can be downloaded from the Migraine Action website. Ask the patient to return in a month with the completed diary. A disabling pattern of headaches occurring on every two days or more and with at least two days per week with migraine symptoms is diagnostic of chronic migraine.2
Why has the patient presented now?
With chronic conditions there is often a trigger for presentation and it is important to identify this so that the patient’s concerns can be addressed appropriately. Patients with chronic migraine commonly present when they have become too disabled by the condition to carry out their normal activities or when pain-relieving medications are no longer effective.
Management
Once the diagnosis is confirmed, check for the overuse of pain-relieving medications. Use of these drugs on two or more days per week is indicative of medication overuse. If you are confident in doing so, you should withdraw the patient from the overused drugs and prescribe a steroid for one week or an NSAID for one to two weeks (although not if the patient is overusing an NSAID) to treat any withdrawal symptoms. The use of these medications to break a cycle is sometimes called a bridge and was highlighted in the recent NICE guideline for headache disorders. However, some GPs may treat with amitriptyline from the start, assuming this will mask some of the withdrawal symptoms, but warning the patient that the headaches might flare at first. Once withdrawal is complete, the patient can be managed as described below.
For patients with chronic migraine but no evidence of medication overuse, you should prescribe a preventive medication. In our experience, amitriptyline can be effective for chronic migraine, and is a useful initial treatment. The dose can start as low as 10mg/d and rise in increments to a maximum of 100 mg/d. Amitriptyline is coindicated in patients with depression with anxiety, but contraindicated in those with cardiovascular disease, severe liver disease, mania, pregnancy and lactating mothers. It is important to note that amitriptyline is not approved for chronic migraine in the UK and all prescriptions are off-label. Because no preventive treatment is 100% effective, you may also prescribe strictly limited acute medications for breakthrough attacks, to be taken on no more than two days per week. The patient should continue to complete a headache diary throughout treatment and follow up.
GPs can certainly also try propranolol and pizotifen as prevention but they tend to be less helpful in chronic migraine than high-frequency episodic migraine. Topiramate is still indicated for specialist initiation in the UK. No oral preventative medication is licensed for chronic migraine. Refer the patient to specialist care for further preventive treatments if you are not experienced in using this type of management plan or if the patient is refractory to the initial treatment. Specialist care may involve a GP (working in individual or shared care), a service requested by a GP Commissioning Group or a hospital-based practice, depending on services available locally. Nurses and pharmacists may also conduct specialist services in certain circumstances.
Only two treatments are licensed in the UK for chronic migraine. Botulinum toxin Type A, and the surgical technique of occipital nerve stimulation. Both treatments are currently only available in specialist tertiary care centres, and are indicated for chronic migraine sufferers who are refractory to three or more preventive treatments. Other preventive treatments given for chronic migraine are usually those used for episodic migraine - an antihypertensive such as propranolol, an antiepileptic such as topiramate, or an antidepressant such as amitriptyline. All of these need to be prescribed off-label.
As with episodic migraine, lifestyle issues may exacerbate the problems of chronic migraine. Lifestyle adjustments and trigger-avoidance measures - for example, better sleep hygiene and reducing stress - may be useful. These methods tend to be more effective in episodic rather than chronic migraine, but will certainly do no harm.
Patient information leaflet
Click here to download a handy patient information leaflet on chronic migraine.
Dr Andrew Dowson is Director of King’s Headache Service and King’s College Hospital, London, Clinical Lead at East Kent Headache Service and Chairman of both Migraine in Primary Care Advisors (MIPCA ) and Migraine Action Medical Advisory Board. He is a former full-time GP
Mr Keyoumars Ashkan is a neurosurgeon at King’s College Hospital, London
Competing interests: Dr Dowson has received grants from Allergan UK and St Jude, UK. Mr Ashkan has received educational travel grants from St Jude, UK.
Migraine Action is the main patient support group in the UK for headache sufferers and produces many leaflets about all aspects of migraine, including chronic migraine.
The Migraine in Primary Care Advisors (MIPCA) is a charity concerned with headache management and aimed at the primary care professional. Membership is free – go to www.mipca.org.uk.
The King’s Headache Service is a dedicated headache clinic at King’s College Hospital in London. Dr Ashkan conducts ONS surgery there for suitable patients.
References
1 Headache Classification Committee of the International Headache Society. The international classification of headache disorders; 2nd Edition. Cephalalgia 2004;24(Suppl 1):1–160
2 Olesen J, Bousser M-G, Diener H-C et al. New Appendix Criteria open for a broader concept of chronic migraine. Cephalalgia 2006;26:742–6
