Fibromyalgia syndrome (FMS) is a chronic pain syndrome involving generalized pain for more than three months and tenderness in at least 11 tender points out of 18. Most FMS patients are female (90%) and complain of pain, insomnia, fatigue, and psychological distress.¹ Sleep disorders, chronic fatigue syndrome, irritable bowel syndrome, and mood disorders are often associated with FMS.²

Researchers have found that FMS patients are unusually sensitive to stimuli, which suggests that abnormal central pain mechanisms may play an important role for the increased pain FMS patient’s experience.^3-5 Similarly, migraine patients are unusually sensitive to stimuli, including pain or discomfort when touched. Previous studies have found an increased incidence of FMS among patients with transformed migraine⁶ and it has been hypothesized that episodic migraine, chronic daily headache, and FMS may be phases of the same disorder.⁷

In this study, neurologist Dr. Gal Ifergane of Soroka Medical Center in Beer-Sheva, Israel, and colleagues, enrolled 92 patients with migraine with an without aura, according to the International Headache Society criteria. They aimed to assess the prevalence and severity of FMS among patients with episodic migraine, and to examine the characteristics of patients suffering from both migraine and FMS.

The patients were administered the Headache Impact Test to measure the impact of headache on their lives, and the Migraine Disability Assessment (MIDAS) to measure headache-related disability. Quality of Life was assessed using the SF-36, a test that measures functional status, well-being, and overall health. They were also measured for psychiatric symptom severity, such as depression, anxiety, and obsession-compulsion. Fibromyalgia was diagnosed according to the 1990 American College of Rheumatology classification criteria.

Results
Seventeen percent of the patients with episodic migraine with and without aura met the criteria for FMS, and all of the patients who suffered from both conditions were women (22% of female migraine patients). The prevalence of FMS among migraine patients was significantly higher than in the general population, which is estimated to be between 2-4% in the U.S. (3.4% of women and 0.5% of men).^8-9

Patients with FMS and migraine differed from other female migraine patients in two main ways: they reported a much poorer quality of life and suffered from high levels of mental distress. Dr. Ifergane and colleagues say it is not clear whether the mental distress is caused by the FMS or by migraine, or is an independent factor for either or both of them. They say that either FMS may be an aggravating factor for migraine, or that sensitization of pain pathways due to migraine may aggravate or even cause FMS. It is also possible, they say, that both conditions together may be caused by a third pain-sensitizing factor.

Regardless of the cause, they say the co-existence of FMS-migraine clearly affects the patient’s well-being and should be taken into consideration when choosing treatment strategies. Current treatments include low-dose antidepressants, exercises to strengthen the heart, cognitive behavioural therapy (CBT), and patient education in the treatment of FMS. Antidepressants and CBT are also useful in managing migraine.

References:
1. Wolfe F, et al. The American College of Rheumatology 1990 Criteria for the Classification of Fibromyalgia. Report of the Multicenter Criteria Committee. Arthritis Rheum 1990;33:160-172.
2. Mangweth B, et al. Family study of affective spectrum disorder. Arch Gen Psychiatry 2003;60:170-177.
3. Granges G, Littlejohn G. Pressure pain threshold in pain-free subjects, in patients with chronic regional pain syndromes, and in patients with fibromyalgia syndrome. Arthritis Rheum 1993;36:642-646.
4. Staud R, et al. Temporal summation of pain from mechanical stimulation of muscle tissue in normal controls and subjects with fibromyalgia syndrome. Pain 2003;102:87-95.
5. Graven-Nielson T, et al. Central hyperexcitability in fibromyalgia. J Musculoskel Pain 1999;7:261-271.
6. Peres MFP, et al. Fibromyalgia is common in patients with transformed migraine. Neurology 2001;57:1326-1328.
7. Centonze V, et al. Migraine, daily chronic headache and fibromyalgia in the same patient: an evolutive ‘continuum’ of non organic chronic pain? About 100 clinical cases. Neurol Sci 2004;25:S291-S292.
8. Croft P, et al. The prevalence of chronic widespread pain in the general population. J Rheumatol 1993;20:710-713.
9. Croft P, et al. Population study of tender point counts and pain as evidence of fibromyalgia. BMJ 1994;309:696-699.

Source:
Ifergane G, et al. Prevalence of fibromyalgia syndrome in migraine patients. Cephalalgia 2005: doi:10.1111/j.1468-2982.2005.01060.x.