Sally Aspegren Kendall

Ketamine reduces muscle pain, temporal summation, and referred pain in fibromyalgia patients

&NA; Central mechanisms related to referred muscle pain and temporal summation of muscular nociceptive activity are facilitated in fibromyalgia syndrome (FMS) patients. The present study assessed the effects of an NMDA‐antagonist (ketamine) on these central mechanisms. FMS patients received either i.v. placebo or ketamine (0.3 mg/kg, Ketalar®) given over 30 min on two separate occasions. Habitual pain intensity was assessed on a visual analogue scale (VAS). Initially, 29 FMS patients received ketamine or isotonic saline to determine which patients were ketamine responders (>50% decrease in pain intensity at rest by active drug on two consecutive VAS assessments). Fifteen out of 17 ketamine‐responders were included in the second part of the study. Before and after ketamine or placebo, experimental local and referred pain was induced by intramuscular (i.m.) infusion of hypertonic saline (0.7 ml, 5%) into the tibialis anterior (TA) muscle. The saline‐induced pain intensity was assessed on an electronic VAS, and the distribution of pain drawn by the subject. In addition, the pain threshold (PT) to i.m. electrical stimulation was determined for single stimulus and five repeated (2 Hz, temporal summation) stimuli. The pressure PT of the TA muscle was determined, and the pressure PT and pressure pain tolerance threshold were determined at three bilaterally located tenderpoints (knee, epicondyle, and mid upper trapezius). VAS scores of pain at rest were progressively reduced during ketamine infusion compared with placebo infusion. Pain intensity (area under the VAS curve) to the post‐drug infusion of hypertonic saline was reduced by ketamine (−18.4±0.3% of pre‐drug VAS area) compared with placebo (29.9±18.8%, P<0.02). Local and referred pain areas were reduced by ketamine (−12.0±14.6% of pre‐drug pain areas) compared with placebo (126.3±83.2%, P<0.03). Ketamine had no significant effect on the PT to single i.m. electrical stimulation. However, the span between the PT to single and repeated i.m. stimuli was significantly decreased by the ketamine (−42.3±15.0% of pre‐drug PT) compared with placebo (50.5±49.2%, P<0.03) indicating a predominant effect on temporal summation. Mean pressure pain tolerance from the three paired tenderpoints was increased by ketamine (16.6±6.2% of pre‐drug thresholds) compared with placebo (−2.3±4.9%, P<0.009). The pressure PT at the TA muscle was increased after ketamine (42.4±9.2% of pre‐drug PT) compared with placebo (7.0±6.6%, P<0.011). The present study showed that mechanisms involved in referred pain, temporal summation, muscular hyperalgesia, and muscle pain at rest were attenuated by the NMDA‐antagonist in FMS patients. It suggested a link between central hyperexcitability and the mechanisms for facilitated referred pain and temporal summation in a sub‐group of the fibromyalgia syndrome patients. Whether this is specific for FMS patients or a general phenomena in painful musculoskeletal disorders is not known.

Quantitative sensory testing in fibromyalgia patients and in healthy subjects: identification of subgroups.

ObjectiveTo determine perception and pain thresholds in patients with fibromyalgia syndrome and in healthy controls, and to investigate whether patients with fibromyalgia syndrome can be grouped with respect to thermal hyperalgesia and whether these subgroups differ from healthy controls and in clinical appearance. DesignThe authors conducted a quasi-experimental clinical study. SubjectsTwenty-nine women patients with fibromyalgia syndrome and 21 healthy pain-free age-matched women participated in the study. MethodsQuantitative sensory testing using a Thermotest instrument was performed on the dorsum of the left hand. Sleep and pain intensity were rated using visual analog scales. ResultsCold and heat pain but not perception thresholds differed significantly between patients with fibromyalgia syndrome and healthy subjects. Based on thermal pain thresholds, two subgroups could be identified in fibromyalgia syndrome using cluster analysis. ConclusionPatients with fibromyalgia syndrome were subgrouped by quantitative sensory testing (i.e., thermal pain thresholds). Subgroups show clinical differences in pain intensities, number of tender points, and sleep quality. Cold pain threshold was especially linked to these clinical aspects.

Computerized cuff pressure algometry: a new method to assess deep-tissue hypersensitivity in fibromyalgia

Abstract The aim of this study was to evaluate the use of computerized cuff pressure algometry (CPA) in fibromyalgia (FM) and to correlate deep‐tissue sensitivity assessed by CPA with other disease markers of FM. Forty‐eight women with FM and 16 healthy age‐matched women were included. A computer‐controlled, pneumatic tourniquet cuff was placed over the gastrocnemius muscle. The cuff was inflated, and the subject rated the pain intensity continuously on an electronic Visual Analogue Scale (VAS). The subject stopped the inflation at the pressure‐pain tolerance and the corresponding VAS‐score was determined (pressure‐pain limit). The pressure at which VAS firstly exceeded 0 was defined as the pressure‐pain threshold. Other disease markers (FM only): Isokinetic knee muscle strength, tenderpoint‐count, myalgic score, Beck Depression Inventory, and Fibromyalgia Impact Questionnaire. Student’s T‐test was used to compare pressure‐pain threshold and pressure‐pain tolerance and the Mann–Whitney test to compare pressure‐pain limit. Pearson’s correlation was used to detect linear relationships. Pressure‐pain threshold and pressure‐pain tolerance assessed by CPA were significantly lower in FM compared to healthy controls. There was no difference in pressure‐pain limit. CPA‐parameters were significantly correlated to isokinetic muscle strength where more hypersensitivity resulted in lower strength. Pressure‐pain threshold and pressure‐pain tolerance assessed by CPA were significantly lower in patients with FM indicating muscle hyperalgesia. CPA was associated with knee muscle strength but not with measures thought to be influenced by psychological distress and mood.

Mortality in a cohort of Danish patients with fibromyalgia: Increased frequency of suicide

OBJECTIVE A previous study demonstrated an association between self-reported widespread body pain and increased mortality. The aim of this study was to analyze whether fibromyalgia (FM) and FM-like symptoms are related to increased mortality. METHODS From hospital records, we identified 1,361 patients referred during the period 1984-1999 because of the suspicion of FM. The cases were reviewed by reviewers who were blinded to the outcome. The cohort was followed up for a total of 5,295 person-years at risk and was linked to the Danish Mortality Register. Using the number of years at risk and sex-, age-, and calendar-specific mortality rates from the general population, cause-specific standardized mortality ratios [SMRs] were calculated. RESULTS We observed no overall increased mortality among patients with FM. Among the 1,269 female patients, the SMRs (95% confidence intervals [95% CIs]) for an increased risk of death from suicide, liver cirrhosis/biliary tract disease, and cerebrovascular disease were 10.5 (95% CI 4.5-20.7), 6.4 (95% CI 2.3-13.9), and 3.1 (95% CI 1.1-6.8), respectively. The suicide risk was increased at the time of diagnosis and remained increased after 5 years. Patients meeting the American College of Rheumatology criteria for FM and patients with possible FM had the same cause-specific mortality pattern. No increased cause-specific mortality was observed in the 84 male patients. CONCLUSION The causes of a markedly increased rate of suicide among female patients with FM are at present unknown but may be related to increased rates of lifetime depression, anxiety, and psychiatric disorders. Risk factors for suicide should be sought at the time of the diagnosis of FM and at followup. The results also suggest that risk factors for liver disease and cerebrovascular disease should be evaluated in patients with FM.

A pilot study of body awareness programs in the treatment of fibromyalgia syndrome

OBJECTIVE To compare in a pilot study the effect of two physical therapies, the Mensendieck system (MS) and body awareness therapy (BAT) according to Roxendal, in fibromyalgia patients and to investigate differences in effect between the two interventions. METHODS Twenty female patients were randomized to either MS or BAT in a program lasting 20 weeks. Evaluations were tender point examination and questionnaires, including visual analog scales (pain intensity at worst site, muscular stiffness, evening fatigue, and global health), Fibromyalgia Impact Questionnaire (FIQ), Coping Strategies Questionnaire, Quality of Life Scales, Arthritis Self-Efficacy Scale (ASES), and disability before, immediately after, and at 6 and 18 months follow-up. RESULTS The BAT group had improved global health at 18 months follow-up, but lower results than the MS group. The MS group had improved FIQ, ASES other symptoms, and pain at worst site at 18 months follow-up. CONCLUSION In the present pilot study, MS was associated with more positive changes than BAT.

Muscle metabolism in fibromyalgia studied by P‐31 magnetic resonance spectroscopy during aerobic and anaerobic exercise

Objective: To investigate mechanisms underlying the reduced work capacity of fibromyalgia (FM) patients were compared to healthy controls at specified workloads, using P‐31 magnetic resonance spectroscopy (MRS). Methods: The forearm flexor muscle group was examined with MRS at rest, at sub maximal and at maximal controlled dynamic work as well as at maximal isometric contraction. Aerobic fitness was determined by bicycle ergonometry. Results: Metabolite concentrations and muscle pH were similar for patients and controls at lower workloads. At maximal dynamic and static contractions the concentration of inorganic phosphate was lower and at static contractions the pH decrease was smaller in patients. The performed work by patients was only 50% compared to controls and the patients experienced more pain. Maximal oxygen uptake was lower in the fibromyalgia group. Expired gas‐analysis in this group showed ventilatory equivalents at similar relative levels of maximal work capacity. Conclusion: Fibromyalgia patients seem to utilise less of the energy rich phosphorous metabolites at maximal work despite pH reduction. They seemed to be less aerobic fitted and reached the anaerobic threshold earlier than the controls.

ARE PERCEIVED MUSCLE TENSION, ELECTROMYOGRAPHIC HYPERACTIVITY AND PERSONALITY TRAITS CORRELATED IN THE FIBROMYALGIA SYNDROME?

The study was performed to investigate the relationship between perceived muscle tension and electromyographic hyperactivity and to what extent electromyographic (EMG) hyperactivity relates to personality traits in fibromyalgics. Thirty-six females with fibromyalgia performed isokinetic maximal forward flexions of the shoulder combined with surface EMG recordings of the trapezius and infraspinatus muscles. Signal amplitude ratio and peak torque were calculated in the initial and endurance test phases. Pain intensity, perceived general and local shoulder muscle tension, and personality traits using the Karolinska Scales of Personality were assessed pre-test. Neither perceived muscle tension nor muscular tension personality trait correlated with EMG muscle hyperactivity. Perceived general muscle tension correlated with aspects of anxiety proneness (including muscle tension) of the Karolinska Scales of Personality. Pain intensity interacted with many of the variables. We propose that when patients with fibromyalgia report muscle tension that they may be expressing something other than physiological muscle tension.

Feldenkrais Intervention in Fibromyalgia Patients: A Pilot Study

Objectives: To evaluate the effect of the Feldenkrais intervention, in fibromyalgia patients. Methods: Twenty fibromyalgia patients started Feldenkrais intervention done as one individual and two group sessions weekly for 15 weeks. Nineteen started a group-based pain education program followed by a pool program. Test and self-report questionnaires were administered at the start, at six month follow up, and at the end of intervention. Results: After the Feldenkrais intervention improvement in balance and trends to better lower extremity muscle function were shown, but the improvements were not maintained. Conclusions: No sustained benefit of the Feldenkrais intervention compared to a pool program was seen. Methodological problems are discussed.

Differences in sensory thresholds in the skin of women with fibromyalgia syndrome : A comparison between ketamine responders and ketamine non-responders

Objectives: To compare detection and pain thresholds in the skin of female fibromyalgia patients who were either ketamine responders or ketamine nonresponders. Methods: Detection thresholds to innocuous warmth, of cold, heat or cold pain, and touch and dynamic touch sensation were determined in the skin. Pressure pain thresholds, local and widespread pain intensity, and pain duration were also registered. Results: Ketamine nonresponse was associated with more pronounced hypersensitivity for thermal pain [especially cold pain] than ketamine response. Conclusions: Blockade of N-metyl-D-aspartic acid receptors by ketamine and the recording of pain thresholds in the skin, especially for cold pain, might reveal different mechanisms of allodynia.

The effect of a session of exercise of moderate intensity level on pressure pain thresholds in healthy women

The aim of this investigation was to study in healthy women the effect of a moderately intensive physical exercise session on the pressure pain thresholds of tendon, bone and muscle. Twenty-four healthy women in the 7-14th day of the menstruation cycle took part in a 60-min exercise class. Pressure pain thresholds were measured by electronic algometer at four points before and after the class. Habitual exercise habits and perceived class exercise intensity were recorded. There was no change in pressure pain sensitivity at any site. Increased pressure pain thresholds tended to be linked to older age and later day in the follicular phase of the menstrual cycle. In conclusion, a single session of moderate exercise in an exercise setting outside the healthcare system or the laboratory did not increase pressure pain thresholds at group level in healthy women.