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Biomedical subjects

Lars Bendtsen

Publications and source records attributed to Lars Bendtsen.

14 recordsLinked to original sources
PubMed2007

Predictors of treatment outcome in headache patients with the Millon Clinical Multiaxial Inventory III (MCMI-III).

The objective was to discover possible psychological factors influencing treatment outcome for headache patients referred to psychological treatment in a tertiary headache centre by initial assessment using the Millon Clinical Multiaxial Inventory III (MCMI-III). The MCMI-III was administered to 136 referred patients. Patients with valid protocols who had completed their treatment by October 2003 were included. Multidisciplinary treatment was offered including psychological treatment, mainly pain and stress management, pharmacological treatment and physiotherapy. Medians of MCMI-III scales for patients with and without reduction in headache frequency were compared. All of the eligible 58 patients were included in the study. Patients with reduction in headache frequency after treatment had lower scores on the MCMI-III Somatoform, Major depression and Avoidant personality pattern scales and higher scores on the Alcohol Dependence, Self-Defeating personality pattern, Depressive personality pattern, Drug Dependence, Aggressive personality pattern and Bipolar: Manic scales before treatment compared to patients without effect. Patients with a positive treatment effect reported less symptoms of depression and seemed less inclined to somatisation than non-responders. Responders also appeared more likely to experience increased social or occupational distress and report difficulties with handling emotions and an enduring tendency to focus on negative aspects of the self-image. The results can give valuable information regarding treatment planning and development.

Female↗
PubMed2006

Increased muscle pain sensitivity in patients with tension-type headache.

Nociceptive mechanisms in tension-type headache are poorly understood. The aim was to investigate the pain sensitivity of pericranial muscles and a limb muscle in patients with tension-type headache. Experimental muscle pain was induced by standardized infusions of 0.5 ml of 1 M hypertonic saline into two craniofacial muscles (anterior temporalis (TPA) and masseter (MAS)) and a limb muscle (anterior tibial (TA)) in 24 frequent episodic tension-type headache patients (FETTH), 22 chronic tension-type headache patients (CTTH) and 26 age and gender matched healthy subjects. Headache patients were examined twice, both on days with and on days without headache. The pressure pain thresholds (PPTs) were determined before and after infusions. The subjects continuously reported intensity of saline-induced pain on an electronic visual analogue scale (VAS) and the perceived area of pain was drawn on anatomical maps. Headache patients demonstrated significantly lower PPTs, higher saline-evoked VAS pain scores and greater pain areas than healthy subjects at all the tested muscle sites (P<0.05). There was a significant gender difference for the PPTs in all three groups of participants (P<0.05) and for VAS pain scores in the CTTH patients (P<0.05). There was no difference in pain sensitivity between FETTH and CTTH or between patients with or without headache. In conclusion, the present study demonstrates the presence of generalized pain hypersensitivity both in FETTH and CTTH compared to controls which is unrelated to actual headache status and extends to include responses to longer-lasting stimuli which are clinically highly relevant. Gender differences in deep pain sensitivity seem to be a consistent finding both in healthy controls and patients with tension-type headache.

Female↗
PubMed2006

[Headache Classification, new edition].

Headache is extremely prevalent and experienced by almost everyone. A clinical test for the diagnosis of headache is still lacking, and a detailed clinical description is therefore essential for a precise diagnosis. The second edition of the International Headache Classification is presented, along with a translation into Danish. The major changes from the first edition are a detailed description of several subtypes of migraine, three subdivisions of tension-type headache according to frequency of headache and a major extension of the chapter concerning secondary headaches due to medication overuse. General knowledge of the major subforms of primary and secondary headaches is a very important tool for diagnosis and treatment.

Headache Disorders↗
PubMed2006

Tension-type headache: why does this condition have to fight for its recognition?

Tension-type headache is the most prevalent type of primary headache but is frequently forgotten by the patient and doctor. This article summarizes the present knowledge about tension-type headache and discusses some of the problematic aspects. Most patients in specialized headache clinics suffer from several different primary and secondary headaches at the same time and deserve a careful characterization before a rational therapy can be initiated. In particular, it is of utmost importance to increase focus on clinical and basic research in order to develop effective treatment strategies for the most neglected and most costly type of headache.

Diagnosis, Differential↗
PubMed2006

Tension-type headache: the most common, but also the most neglected, headache disorder.

PURPOSE OF REVIEW: Tension-type headache is the most common type of headache and, in its chronic form, one of the most neglected and difficult types of headache to treat. Recently published data will be reviewed. RECENT FINDINGS: The prevalence of frequent tension-type headache increased significantly from 1989 to 2001, and several risk factors have been identified. The incidence decreases markedly with age. The prognosis is fairly favorable for the episodic forms. Chronic tension-type headache, coexisting migraine, sleep problems and not being married were identified as risk factors for a poor outcome. Previous reports of sensitization of the central nervous system in patients with chronic tension-type headache were confirmed by the findings of generalized pain hypersensitivity both in skin and in muscles, and of a decrease in the volume of gray matter in brain structures. A promising new animal model of tension-type headache has been developed. In addition, the efficacy of a prophylactic drug, mirtazapine, with fewer side-effects than the tricyclic antidepressants has been demonstrated. SUMMARY: The new data on the prevalence, incidence and prognosis of tension-type headache are valuable for health care planning and in daily clinical practice. The increased knowledge with regard to abnormal central pain modulation, together with the development of an animal model, hold promise for much-needed improvements in the understanding of pathophysiological mechanisms and treatment.

Humans↗
PubMed2005

Pathophysiology of tension-type headache.

Tension-type headache is one of the most common primary headache disorders. Advances in basic pain and clinical research have improved our understanding of pathophysiologic mechanisms of tension-type headache. Increased excitability of the central nervous system generated by repetitive and sustained pericranial myofascial input may be responsible for the transformation of episodic tension-type headache into the chronic form. Studies of nitric oxide (NO) mechanisms suggest that NO may play a key role in the pathophysiology of tension-type headache and that the antinociceptive effect of nitric oxide synthase inhibitors may become a novel principle in the future treatment of chronic headache. Future studies should focus on investigation of the source of peripheral nociception, the role of descending pain modulation, and the development of an animal model of tension-type headache to support the pathophysiologic importance of central sensitization in tension-type headache.

Humans↗
PubMed2005

No release of interstitial glutamate in experimental human model of muscle pain.

Glutamate may be released from muscle nociceptors and thereby contribute to mechanisms underlying acute and chronic muscle pain. In vivo concentration of glutamate during muscle pain has not previously been studied in either animals or humans. In the present study, we aimed to study the in vivo concentration of glutamate before, during and after acute pain of trapezius muscle in humans using the microdialysis technique. In addition, we examined the nutritive skeletal muscle blood flow and the interstitial concentrations of lactate, glucose, glycerol, pyruvate and urea. Experimental pain and tenderness were induced by intramuscular infusion of a chemical mixture consisting of bradykinin, prostaglandin E(2), histamine and serotonin. One EMG-needle and one microdialysis catheter were inserted into non-dominant and dominant trapezius muscles on a standard anatomical point in 19 healthy subjects. Dialysates were collected at rest, during infusion and 60 and 120 min after stop of infusion. Local tenderness was recorded at baseline and at the end of experiment. Local pain was recorded during infusion. The infusion of chemical mixture was more painful than infusion of placebo (p < 0.05) and resulted in significantly higher local tenderness score than placebo (p = 0.007). There was no difference in change in interstitial concentrations of glutamate, lactate, glucose, glycerol, pyruvate and urea from baseline to infusion and post-infusion periods between chemical mixture and placebo (p > 0.05). Muscle blood flow increased significantly over time in response to infusion of chemical mixture and placebo (p = 0.001). However, we found no difference in changes in muscle blood flow between chemical mixture and placebo (p > 0.05). In conclusion, the present study demonstrates no signs of increased release of glutamate from myofascial nociceptors during and after acute experimentally induced muscle pain and tenderness.

Acute Disease↗
PubMed2004

Mirtazapine is effective in the prophylactic treatment of chronic tension-type headache.

BACKGROUND: The tricyclic antidepressant amitriptyline is the only drug with prophylactic efficacy for chronic tension-type headache. However, amitriptyline is only moderately effective, with headache reduction of approximately 30%, and treatment is often hampered by side effects. Mirtazapine is a relatively new so-called noradrenergic and specific serotonergic antidepressant, which is more specific and therefore generally better tolerated. OBJECTIVE: To evaluate the efficacy of mirtazapine. METHODS: Twenty-four nondepressed patients with chronic tension-type headache were included in a randomized, double-blind, placebo-controlled, crossover trial. All patients had tried numerous other treatments. Mirtazapine 15 to 30 mg/day or placebo was each given for 8 weeks separated by a 2-week wash-out period. RESULTS: Twenty-two patients completed the study. The primary efficacy variable, area-under-the-headache curve (AUC; duration x intensity), was lower during treatment with mirtazapine (843) than during treatment with placebo (1,275) (p = 0.01). Mirtazapine also reduced the secondary efficacy variables headache frequency (p = 0.005), headache duration (p = 0.03), and headache intensity (p = 0.03) and was well tolerated. CONCLUSIONS: Mirtazapine reduced AUC by 34% more than placebo in difficult-to-treat patients. This finding is clinically relevant and may stimulate the development of prophylactic treatments with increased efficacy and fewer side effects for tension-type headache and other types of chronic pain.

Adrenergic alpha-2 Receptor Antagonists↗
PubMed2004

Analgesic effect of amitriptyline in chronic tension-type headache is not directly related to serotonin reuptake inhibition.

The tricyclic antidepressant amitriptyline is the only documented and most widely used prophylactic drug for chronic tension-type headache (CTTH). However, it is not fully clarified whether the serotonin (5-HT) reuptake inhibition plays a major role for the analgesic effect of amitriptyline. To explore the importance of 5-HT reuptake inhibition for mechanism of action of the analgesic effect of amitriptyline we investigated platelet 5-HT levels during preventive treatment of CTTH with amitriptyline, the selective serotonin reuptake inhibitor citalopram, and placebo. Thirty-four patients with CTTH were given preventive treatment with amitriptyline 75 mg/day, the selective 5-HT reuptake inhibitor citalopram 20 mg/day, and placebo in a 32-week, double-blind, placebo-controlled, three-way crossover trial. Blood samples were collected in the last week of each treatment period. Platelet 5-HT was used as a measure of 5-HT reuptake inhibition and determined by high performance liquid chromatography. Area under the headache curve was 308 (157-715) (median with quartiles in parentheses) with amitriptyline and significantly lower than 377 (158-1121) with citalopram (P = 0.04) and 441 (178-1408) with placebo (P = 0.002). There was no difference between citalopram and placebo (P = 0.23). Platelet 5-HT was 0.4 (0.3-0.7) x 10(-18)mol/platelet with citalopram, which was significantly lower than 1.7 (1.2-2.4) x 10(-18)mol/platelet with amitriptyline (P < 0.001), and 3.5 (2.8-4.3) x 10(-18)mol/platelet with placebo (P < 0.001). The lower platelet 5-HT during treatment with citalopram than amitriptyline indicates that 5-HT reuptake was most effectively inhibited by citalopram. In contrast, amitriptyline was most effective in reduction of headache. This suggests that the analgesic effect of amitriptyline in CTTH is not solely due to 5-HT reuptake inhibition and that other mechanisms such as norepinephrine reuptake inhibition, NMDA receptor antagonism, blockade of muscarinic receptors and ion channels should be addressed in the future research.

Adolescent↗
PubMed2003

Central and peripheral sensitization in tension-type headache.

Recent studies on tension-type headache indicate that the nociceptive input to the central nervous system may be increased as a result of activation or sensitization of peripheral sensory afferents. Moreover, pain perception studies and pharmacologic studies strongly suggest that the central nervous system is sensitized in patients with chronic tension-type headache. The barrage of nociceptive impulses from the periphery may be responsible for the sensitization of second- and third-order neurons in the central nervous system. In this way, sensitization may play a role in the initiation and maintenance of tension-type headache. Studies have demonstrated that treatment with drugs that counteract sensitization has an analgesic effect on tension-type headache. Targeting this mode of action seems to be a promising way of improving the treatment for this prevalent disorder.

Animals↗
PubMed2003

Experimental muscle pain and tenderness following infusion of endogenous substances in humans.

Several human models of myofascial pain exist, but none are similar to clinical pain. The aim of the present study was to develop a clinically relevant model of prolonged human myofascial pain using infusion of the naturally occurring endogenous substances. Initially, bradykinin (Bk), serotonin (5-hydroxytryptamine (5-HT)), histamine (His), prostaglandin E(2) (PGE(2)), adenosine-tri-phosphate (ATP), and their combinations were infused into the trapezius muscle of 36 healthy subjects in a total of 67 sessions to identify substances, which could induce a moderate muscle pain. PGE(2), ATP, and a combination of Bk, 5-HT, His, and PGE(2) produced the intended moderate pain. These substances were further examined in a randomised, blinded, placebo-controlled dose-finding design in 15 healthy subjects in 68 sessions. PGE(2) (3, 6, and 12 nmol/ml) induced mild pain and tenderness not different from placebo. ATP (9000, 18,000, and 36,000 nmol/ml) induced pain of moderate to strong intensity (P=0.04) and the dose of 18,000 nmol/ml furthermore produced moderate local tenderness (P=0.04). Because of unacceptable side effects in subsequent examinations, further studies of ATP in humans were suspended. Infusion of the combination of Bk (92 nmol), 5-HT (156 nmol), His (140 nmol), and PGE(2) (1.95 nmol) produced a moderate pain intensity (P=0.04) and mild tenderness (P=0.04) without inducing unacceptable side effects. Intramuscular infusion of a combination of Bk, 5-HT, His, and PGE(2) induced a prolonged moderate pain and tenderness in healthy humans, and this model may be a valuable tool in future studies of the pathophysiological mechanisms of myofascial pain.

Adult↗
PubMed2002

Sensitization: its role in primary headache.

The pathophysiology of the two most common primary headaches, migraine and tension-type headache, is complex and not yet fully understood. Recent animal and human studies examining these headaches indicate that the nociceptive input to the central nervous system (CNS) may be increased due to activation or sensitization of peripheral sensory afferents. The barrage of nociceptive impulses may result in sensitization of second- and third-order neurons in the CNS. In this way, sensitization may play a role in initiation and maintenance of migraine and tension-type headache. It is likely that the effects of established medication for both disorders may be partly due to a reduction in sensitization. Several interesting drugs that counteract sensitization are under development, and targeting this mode of action seems to be a promising way of improving the treatment for these prevalent disorders.

Animals↗
PubMed1994

Muscle palpation with controlled finger pressure: new equipment for the study of tender myofascial tissues.

While manual palpation is the most important method for evaluation of tender myofascial tissues, it lacks reliability. Therefore, we have developed an instrument, called a 'palpometer', which allows the measurement of pressure exerted during palpation. The palpometer consists of a thin pressure-sensitive plastic device attached to the palpating finger, and of a scale recording the pressure applied to the device. Known forces were applied to the pressure sensitive device under various experimental conditions and the corresponding values were read on the palpometer scale. Then 14 observers, blinded to the palpometer scale, palpated the temporal muscle on the same subject twice, with an interval of 1 week. A highly significant correlation was found between palpometer recordings and forces applied to the pressure-sensitive device (P < 0.0001). Exerted force at a given palpometer value varied 3.1% within and 7.2% between 2 observers. During palpation of the temporal muscle pressure intensities within the 14 observers did not differ significantly from week to week (P = 0.68). Between the 14 observers pressure intensities varied considerably with a range of 73.5-196 arbitrary units. Thus, a reliable instrument for measuring pressure intensities during palpation of myofascial tissue has been developed. The large variation in palpation pressures between observers indicates that palpation of tender myofascial tissue may be considerably improved by use of the palpometer. This instrument will be indispensable in research studies employing palpation and in the training of physicians to diagnose myofascial pain disorders.

Adult↗