Patients with migraine and comorbid fibromyalgia have heightened somatic hyperalgesia, which is only worsened with chronic migraine, results from a study suggest.
The common co-occurrence of the two disorders suggests a common pathophysiological mechanism; however it is not known how the disorders affect pain sensitivity and symptoms.
In order to assess whether migraine serves as a trigger for fibromyalgia symptoms, researchers analyzed pain thresholds in patients with fibromyalgia (n=40), high frequency episodic migraine (n=41), chronic migraine (n=40), fibromyalgia and high frequency episodic migraine (n=42), and fibromyalgia and chronic migraine (n=40). Patients underwent electrical pain thresholds in skin, subcutis, and muscle and pressure pain thresholds in control sites and tender points. Number of monthly migraine attacks and fibromyalgia flares were also recorded over 3 months.
The lowest electrical and pressure thresholds at all sites were recorded in patients with fibromyalgia and comorbid chronic migraine, followed by patients with fibromyalgia and comorbid episodic migraine, fibromyalgia, chronic migraine, and episodic migraine (P<0.0001). Monthly fibromyalgia flares were progressively higher in patients with just fibromyalgia, fibromyalgia and comorbid episodic migraine, and fibromyalgia and comorbid chronic migraine (P<0.0001). Nearly 87% of flares occurred with 12 hours of a migraine attack in comorbid patients (P<0.0001).
In comorbid patients, effective use of migraine prophylaxis (calcium-channel blockers) produced a significant improvement in fibromyalgia symptoms and reduction of rescue medications and migraine attacks compared to patients who did not receive prophylaxis (P<0.0001). Electrical pain and pressure pain thresholds both significantly increased in the treatment group compared to non-treated patients.
The results suggest that prevention of chronic migraine may help prevent the development of fibromyalgia in pre-disposed patients and worsening of fibromyalgia symptoms in patients with comorbid migraine and fibromyalgia.