Effects of treatment of peripheral pain generators in fibromyalgia patients.

Fibromyalgia syndrome (FS) frequently co-occurs with regional pain disorders. This study evaluated how these disorders contribute to FS, by assessing effects of local active vs placebo treatment of muscle/joint pain sources on FS symptoms. Female patients with (1) FS+myofascial pain syndromes from trigger points (n=68), or (2) FS+joint pain (n=56) underwent evaluation of myofascial/joint symptoms [number/intensity of pain episodes, pressure pain thresholds at trigger/joint site, paracetamol consumption] and FS symptoms [pain intensity, pressure pain thresholds at tender points, pressure and electrical pain thresholds in skin, subcutis and muscle in a non-painful site]. Patients of both protocols were randomly assigned to two groups [34 each for (1); 28 each for (2)] to receive active or placebo local TrP or joint treatment [injection/hydroelectrophoresis] on days 1 and 4. Evaluations were repeated on days 4 and 8. After therapy, in active--but not placebo-treated-- groups: number and intensity of myofascial/joint episodes and paracetamol consumption decreased and pressure thresholds at trigger/joint increased (p<0.001); FS pain intensity decreased and all thresholds increased progressively in tender points and the non-painful site (p<0.0001). At day 8, all placebo-treated patients requested active local therapy (days 8 and 11) vs only three patients under active treatment. At a 3-week follow-up, FS pain was still lower than basis in patients not undergoing further therapy and had decreased in those undergoing active therapy from day 8 (p<0.0001). Localized muscle/joint pains impact significantly on FS, probably through increased central sensitization by the peripheral input; their systematic identification and treatment are recommended in fibromyalgia.

A randomized, controlled study comparing a lidocaine patch, a placebo patch, and anesthetic injection for treatment of trigger points in patients with myofascial pain syndrome: evaluation of pain and somatic pain thresholds.

BACKGROUND: Myofascial pain syndrome (MPS), a regional pain condition caused by trigger points in muscle or muscle fascia, produces muscle pain, tenderness, and disability. The gold standard of treatment for MPS-infiltration of trigger points with anesthetic-may provoke discomfort to the patients and require medical intervention. OBJECTIVES: This study was designed to compare the effects of a topical lidocaine patch, a placebo patch, and injection of anesthetic (infiltration) for the symptoms of MPS in terms of pain, disability, and local tissue hypersensitivity, and to determine the acceptability of the lidocaine patch to the patients. METHODS: Patients were randomly allocated to receive 1 of 3 treatments: a lidocaine patch applied to the trigger point for 4 days (replacement every 12 hours; total daily dose, 350 mg), a placebo patch applied to the trigger point for 4 days (replacement every 12 hours), or infiltration of the trigger point with two 1-mL injections of 0.5% bupivacaine hydrochloride given 2 days apart. Treatment with the patches was double-blinded, whereas treatment with infiltration was single-blinded. The number of pain attacks, pain intensity at rest and on movement, and pain-related interference with daily activity, work activity, mood, and quality of life were recorded before, during, and after treatment using a visual analog scale (VAS). Pressure and electrical pain thresholds of the skin, subcutis, and muscle in the trigger point, target area, and a pain-free area were evaluated before starting therapy (day 1) and on days 5 and 9. A VAS was used to measure discomfort from therapy, and a diary was given to each patient to record requests for additional treatment (if needed) and adverse effects. RESULTS: Sixty white patients (46 women and 14 men) 19 to 76 years of age were studied. Mean (SD) age was 46.88 (15.37) years, and mean (SD) weight was 69.58 (13.94) kg. Twenty patients were assigned to each treatment group. Subjective symptoms did not change with placebo, but decreased significantly with the lidocaine patch and infiltration (both, P < 0.001) relative to baseline. Pain thresholds did not vary with the placebo patch, but increased significantly with the lidocaine patch and infiltration (all, P < 0.001); effects at muscle trigger points and target areas were greater with infiltration. Discomfort from therapy was greater with infiltration than with the lidocaine patch. Only patients in the placebo group requested additional treatment (P < 0.001). No adverse events occurred in any group. CONCLUSION: Lidocaine patches were effective in, and highly acceptable to, these patients with MPS and high tissue hypersensitivity.

Contribution of myofascial trigger points to migraine symptoms.

UNLABELLED: This study evaluated the contribution of myofascial trigger points (TrPs) to migraine pain. Seventy-eight migraine patients with cervical active TrPs whose referred areas (RAs) coincided with migraine sites (frontal/temporal) underwent electrical pain threshold measurement in skin, subcutis, and muscle in TrPs and RAs at baseline and after 3, 10, 30, and 60 days; migraine pain assessment (number and intensity of attacks) for 60 days before and 60 days after study start. Fifty-four patients (group 1) underwent TrP anesthetic infiltration on the 3rd, 10th, 30th, and 60th day (after threshold measurement); 24 (group 2) received no treatment. Twenty normal subjects underwent threshold measurements in the same sites and time points as patients. At baseline, all patients showed lower than normal thresholds in TrPs and RAs in all tissues (P < .001). During treatment in group 1, all thresholds increased progressively in TrPs and RAs (P < .0001), with sensory normalization of skin/subcutis in RAs at the end of treatment; migraine pain decreased (P < .001). Threshold increase in RAs and migraine reduction correlated linearly (.0001 < P < .006). In group 2 and normal subjects, no changes occurred. Cervical TrPs with referred areas in migraine sites thus contribute substantially to migraine symptoms, the peripheral nociceptive input from TrPs probably enhancing the sensitization level of central sensory neurons. PERSPECTIVE: This article shows the beneficial effects of local therapy of active myofascial trigger points (TrPs) on migraine symptoms in patients in whom migraine sites coincide with the referred areas of the TrPs. These results suggest that migraine pain is often contributed to by myofascial inputs that enhance the level of central neuronal excitability.