Melatonin in serum and urine in patients with idiopathic pain syndromes

In 16 healthy volunteers, 16 patients with neurogenic pain syndromes, 37 patients with idiopathic pain syndromes, and 30 depressed patients, melatonin in serum was determined at 2 a.m. when the peak concentration was expected. In a somewhat larger series comprising 53 healthy volunteers, 14 patients with neurogenic pain syndromes, and 35 patients with idiopathic pain syndromes, melatonin was measured in urine collected during the night in a standardized manner. Chronic pain patients (with neurogenic or idiopathic pain disorders) and depressed patients had significantly lower melatonin in serum at 2 a.m. than healthy volunteers. Chronic pain patients also had significantly lower melatonin in urine than healthy volunteers, even when age, sex, and body weight were taken into account. The low melatonin concentrations were related to increased depressive symptomatology, especially sadness, bodily discomfort, inner tension, concentration difficulties, and pain. As low concentrations of melatonin in serum and urine also are found in patients with depressive disorders, the results are in line with the suggestion that the chronic idiopathic pain syndrome may be a variant of depressive disease, or the two syndromes may share a common pathogenic mechanism.     

Platelet MAO in patients with idiopathic pain disorders

Summary Patients with idiopathic pain syndromes have been compared to healthy volunteers and patients with neurogenic pain syndromes as concerns the activity of the enzyme monoamine oxidase (MAO) in thrombocytes. In both patients with idiopathic pain syndromes and in patients with neurogenic pain syndromes an increased frequency of patients with low platelet MAO activity was found.As low platelet MAO activity has been suggested to reflect low central serotoninergic activity the results are in line with findings of reduced concentrations of the serotonin metabolite 5-HIAA in CSF in patients with idiopathic pain syndromes.The results would also give some support for the suggestion that idiopathic pain syndromes might be a variant of depressive disease.     

Personality traits in patients with idiopathic pain disorder

In the present study, patients with idiopathic pain syndromes have been compared to healthy volunteers, patients with neurogenic pain syndromes and depressed patients as concerns stable personality traits. The personality traits were assessed by means of the Karolinska Scales of Personality (KSP). Patients with idiopathic pain syndromes were found to have high scores on scales measuring Muscular tension, Social desirability, Psychasthenia and Socialization. They had also high scores on the Inhibition of aggression factor. They had low scores on Impulsivity, Monotony avoidance, Indirect aggression, Verbal aggression and Suspicion. As compared to depressed patients, the pain patients were much more controlled, with higher scores on Socialization and Social desirability scales and like depressed patients with a tendency to inhibit aggression. Thus, as compared to depressed patients, the pain patients had less open anxiety but the same degree of muscular tension.     

5-HIAA and HVA in CSF in patients with idiopathic pain disorders

Patients with idiopathic pain syndromes were compared with healthy volunteers and with patients suffering from chronic pain syndromes of neurogenic origin, with respect to the concentrations of the metabolites 5-hydroxy-indole-acetic acid (5-HIAA) and homovanillic acid (HVA) in cerebrospinal fluid (CSF). Patients with idiopathic pain syndromes were subdivided according to the presence or absence of somatic lesions. It was found that these groups did not differ in concentrations of 5-HIAA or HVA, at least not when values were corrected for age, sex, and body height. Patients with idiopathic pain syndromes were found to have low concentrations of 5-HIAA, but not of HVA, in CSF. These differences were also obvious when the values were corrected for age, sex, and body height. As low concentrations of 5-HIAA in CSF have previously been demonstrated in patients with depressive disorders, our results support the suggestion by Blumer and Heilbronn (1982) that the idiopathic pain syndrome is a variant of depressive disease. At least the two syndromes share a common pathogenetic mechanism--a disturbance in serotonergic turnover.     

Motor responses in transcranial magnetic stimulation and somatosensory evoked potentials in patients with pain syndromes

The main goal was to evaluate the motor and somatosensory systems by recording evoked motor responses (EMRs) during transcranial magnetic stimulation (TMS) and somatosensory evoked potentials (SEPs) in patients with neurogenic pain syndromes before and after implantation of the systems for chronic antipain epidural stimulation. Fifteen patients with neurogenic pain syndromes and a control group of 15 apparently healthy examinees were examined. The patients were found to have a significant reduction in the motor thresholds of EMRs during TMS and an increase in the amplitude of EMRs after implantations of the systems. There were no significant changes in the amplitude-time characteristics of short SEPs as compared to the healthy examinees and after implantation of the systems. Analysis of the amplitude-time characteristics of long SEPs in these patients revealed a significant increase in the amplitude of the component P250 as compared to the normal values and its decrease after implantation of the systems.     

Somatosensory evoked potentials and noxious stimulation in patients with intractable,noncancer pain syndromes

Investigations of the evoked potentials (EPs) to noxious laser stimulation have indicated consistent strong linear relationships between subjective response (R), stimulus intensity (S), and EP amplitude (A). Thirty patients with chronic intractable benign pain syndromes (CIBPS) were tested to determine whether their patterns differed from previous studies with normal volunteers. Nearly half of the CIBPS patients were found to be relatively insensitive to acute pain stimuli. A large number were also found to show negative relationships between S and A. These differences from control subjects were considered of potential importance in their implications concerning the nature of chronic pain and its differences from the acute pain process.     

Substance P-like immunoreactivity and somatostatin-like immunoreactivity in the ventricular fluid of patients with chronic pain syndromes

Summary Substance P-like and somatostatin-like immunoreactivities (SPLI and SLI) were determined in ventricular fluid of patients with chronic pain syndromes and in a comparison group with multiple sclerosis, essential tremor, epilepsy and postanoxic myoclonus. Concentrations of SPLI and SLI were non-significantly decreased by 40% and 33% in chronic pain patients as compared with control patients without pain. There were no differences apparent between subgroups of pain patients (deaferentation pain, neoplasia-induced pain, thalamic pain). High pressure liquid chromatography combined with radioimmunoassay showed marked heterogeneity of SPLI and SLI.     

Acute and chronic pain syndromes in multiple sclerosis

A representative sample of 117 patients with definite multiple sclerosis (MS) was interviewed on pain syndromes. Chronic syndromes lasting more than one month included dysaestesthesia, low back pain, spasms, tonic seizures, tightening and painful sensations in the extremities. Acute syndromes included neuralgia, L'Hermitte's sign and pain associated with optic neuritis. Thirty-five per cent were pain-free. Of the remaining patients had 45% pain at the time of the examination, 32% indicated pain among the most severe symptoms of MS and 23% had pain at the onset of MS. The number of patients with pain at the time of the examination increased with age and duration of disease. Patients with pain were significantly more often spastic and significantly more often sought alternative treatment forms. No difference was found for mean age, sex, physical impairment, duration of disease from onset of MS, depressive score and score of delayed verbal memory.     

Facial pain, distress, and immune function

Chronic facial pain syndromes are associated with high levels of distress and depression. Immune system measures were investigated in otherwise healthy patients suffering from chronic temporomandibular pain and dysfunction syndrome (TMPDS) and in matched controls. No mean differences were found between TMPDS patients and the controls on any of the immune measures; however, both ConA and PWM responses in TMPDS patients were decreased in relation to the level of demoralization (P less than 0.05). Cognitive symptoms such as low self-esteem and perceptions of helplessness/hopelessness were implicated in these effects. In addition, among patients pain severity was independently associated with decreased ConA response (P less than 0.05). The data suggest possible correlates of stress-induced changes in the immune system.     

Gabapentin use in neuropathic pain syndromes

The development of neuropathic pain involves a series of changes including primary and secondary hyperalgesia, peripheral and central sensitization, and wind-up phenomena. Neurotransmitters play a critical role in this process. For example, glutaminergic subtypes of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and neurokinin prime the N-methyl-D-aspartate (NMDA) receptor by triggering the release of intracellular calcium ions, thus unblocking the magnesium ion plug on the NMDA receptor and allowing Ca2+ influx into the cell. Ca2+ ions acting as secondary messengers initiate protein kinase C activation, phospholipase C and nitric oxide synthetase production, and proto-oncogene expression. The activation of the NMDA receptor thereby increases the responsiveness of the nociceptive system. Anticonvulsant drugs--including carbamazepine, phenytoin, and felbamate--have been used to treat neuropathic pain. Gabapentin is a novel anticonvulsant that may have a unique effect on voltage-dependent Ca2+ channel currents at postsynaptic dorsal horn neurons. Thus, gabapentin may interrupt an entire series of events, not just a single process, that lead to the development of neuropathic pain. Preclinical models of anti-inflammatory and neuropathic pain indicate that gabapentin effectively antagonizes the maintenance of this pain. Additionally, in preemptive surgical models, gabapentin has been shown to prevent the induction of pain. Gabapentin has been shown to be efficacious in numerous smaller clinical studies, case reports, and chart reviews in a variety of neuropathic pain syndromes. Two large multicenter studies, one in postherpetic neuralgia (PHN) and one in diabetic peripheral neuropathy (DPN), support preclinical findings. In the PHN study, patients treated with gabapentin demonstrated a significant difference (P<0.001) in their average daily pain score at endpoint compared to placebo patients. In the DPN trial, mean weekly pain was significantly (P<0.001) different for gabapentin-treated patients compared to placebo-treated patients at endpoint. Consistent with the known side-effect profile of gabapentin, the most common adverse events noted in both studies were dizziness and somnolence. Gabapentin should be considered an important addition to the management of neuropathic pain syndromes.     

Positive ego and coping functions in chronic pain and depressed patients

Three groups of elderly subjects (chronic pain patients, patients with major depression, and healthy individuals) were administered measures of self-esteem, ego defense mechanisms, and coping style to examine how these personality components are affected by illness. Ego defense mechanisms and self-esteem for all three groups were not found to be different and were positive except for depressed patients, who used greater levels of projection and demonstrated lower levels of self-esteem. Each subject group utilized equally problem-focused and emotion-focused coping styles. These findings from a preliminary study are consistent with previous research demonstrating stability of personality throughout the life span, and suggest that the psychological functioning of older individuals with chronic pain syndromes or depression remains positive and resilient.     

Yoga intervention and functional pain syndromes: a selective review

Abstract

The definition of functional pain syndromes is varied across literature. No effort has been made to see all functional pain disorder groups under broad nomenclature which would exclude conditions for which pathophysiology is strongly known. Since these disorders are commonly treated with alternative treatment modalities and impose significant burden on health utilization, an effort to look into studies on yoga-based interventions on ‘functional pain syndromes’ (FPS) was made. This study defined FPS as ‘Chronic relapsing remitting pain conditions, the origin of which is difficult to trace with no definite physical pathology on clinical suspicion or available laboratory measures and are valid based on subjective pain reporting, associated distress and socio-occupational dysfunction’. Chronic headache, neck pain, back pain, fibromyalgia, pelvic pain, Irritable Bowel Syndrome, Chronic Fatigue Syndrome, and somatoform pain disorders were included for this review. The review found four meta-analyses on the selected topic both indicating modest efficacy and benefit of yoga in these disorders. Future efforts should be directed to do a large meta-analysis of functional pain syndromes.     

Chronic pain syndromes and their relation to childhood abuse and stressful life events

OBJECTIVE: Childhood abuse, stressful life events, and depression have been repeatedly reported to correlate with chronic pain, but little is known about the mutual relationships among these variables. METHODS: Forty-three women with chronic pelvic pain (CPP), 40 female patients with chronic low-back pain (CLBP), and a female pain-free control group (n=22) were investigated by means of a semistructured interview assessing childhood sexual and physical abuse as well as stressful life events. Additionally, the Beck Depression Inventory (BDI) was used. For multivariate analyses, structured equation modeling was applied. RESULTS: Childhood physical abuse, stressful life events, and depression had a significant impact on the occurrence of chronic pain in general, whereas childhood sexual abuse was correlated with CPP only. Moreover, childhood sexual abuse was related to depression. Both childhood sexual and physical abuse showed a close relationship to an increased occurrence of stressful life events. CONCLUSION: There are complex mutual interactions among childhood abuse, stressful life events, depression, and the occurrence of chronic pain. Therefore, clinicians should take into consideration these psychosocial factors while treating chronic pain patients.     

Long-term effects of spinal cord stimulation in chronic pain syndromes

Summary A total of 50 patients with chronic pain syndromes were selected for treatment with spinal cord stimulation. Correct positioning of electrodes was obtained in 44 patients, leading to an initial alleviation of pain in 25 patients. In 6 patients, electrodes (though still effective in 4) had to be removed because of surgical complications within the first 5 months of use. Only 8 patients had at least some beneficial effect lasting for more than 3 years. The long-term results in patients with more severe psychological disturbances were no worse than those of the other patients.     

A double-blind randomized study of clomipramine versus maprotiline in patients with idiopathic pain syndromes

Seventy patients with idiopathic syndromes were treated with maprotiline, a noradrenaline reuptake inhibitor, or clomipramine, a serotonin reuptake inhibitor in a 6-week, double-blind, randomized, multicenter trial. Fifty-two patients completed the double-blind phase. Overall, 50% of the patients improved. Significant decreases were seen not only in the levels of pain but also in bodily discomfort, sadness an inner tension (determined by visual analogue scales, VAS). A decrease was also found in the frequency of sleep disturbances, intellectual and emotional inhibition, irritability, guilt feelings, retardation, sadness and suicidal ideas (observed ratings). Sixty-three percent of the subjects showed an overall improvement during treatment with clomipramine as compared to 36% during treatment with maprotiline (p less than 0.05). During clomipramine treatment significant decreases were seen on all the six VAS: sadness, bodily discomfort, inner tension, concentration difficulties, memory disturbances and pain. Bodily discomfort and pain were significantly reduced during maprotiline treatment. The effects produced by clomipramine were also significantly greater than the effects caused by maprotiline as concerns psychic anxiety and inhibition (VAS). The overall reduction in VAS was significantly greater with clomipramine when compared to maprotiline. The most important side effects were dry mouth (both drugs) and sweating (clomipramine). However, in the clomipramine group, 8 patients were excluded due to side effects as compared to 1 patient in the maprotiline group. Thus, the results indicate that antidepressants reduce not only pain but are also of clinical value in the treatment of patients with idiopathic pain syndromes. Drugs with pronounced effects on the serotonin reuptake are to be preferred.     

慢性疼痛与器质性疼痛心理学特征的对照研究

目的 旨在探讨慢性疼痛与器质性疼痛心理学特征的差异。方法 采用ＳＣＬ－９０、ＬＥＳ、ＳＳＲＳ、ＤＳＱ、ＨＡＭＤ、ＨＡＭＡ等尽理学量表对５９例慢性疼痛（ＣＰ）与５０例器质性疼痛（ＯＰ）患者进行对照研究,并用ｔ检验对数据进行统计分析。结果 与ＯＰ组相比较,ＣＰ组有较多的生活支持相对缺乏,较易动用不成熟防御方式,有明显的抑郁、焦虑情绪。结论 慢性疼痛与心理社会因素密切相关。     

Complex regional pain syndrome

Abstract Complex regional pain syndrome (CRPS) may develop after limb trauma and is characterized by pain, sensory-motor and autonomic symptoms. Most important for the understanding of the pathophysiology of CRPS are recent results of neurophysiological research. Major mechanism for CRPS symptoms, which might be present subsequently or in parallel during the course of CRPS, are trauma-related cytokine release, exaggerated neurogenic inflammation, sympathetically maintained pain and cortical reorganisation in response to chronic pain (neuroplasticity). The recognition of these mechanisms in individual CRPS patients is the prerequisite for a mechanism-oriented treatment.     

Psychogenic/idiopathic pain syndromes

The concept of psychogenic pain is discussed and reviewed from multiple theoretical perspectives. The validity of psychogenic pain disorder as a clinical diagnosis is also examined, as are regional pain syndromes such as psychogenic abdominal, facial, pelvic, chest, and headache pain. The term "psychogenic pain" is considered to have limited clinical or diagnostic usefulness and the preferred term "idiopathic pain syndrome" used in DSM-III-R is advocated.     

Evidence-based pharmacological treatment of neuropathic pain syndromes

Summary. Neuropathic pain, caused or initiated by a primary lesion in the peripheral or central nervous system, can result in a dramatic reduction in the patients quality of life. The expression neuropathic pain covers a heterogeneous group of conditions, including peripheral neuropathy, complex regional pain syndrome, trigeminal neuralgia and central pain. Neuropathic pain poorly responds to conventional analgesics. However, with appropriate therapy, a significant proportion of patients experience a substantial pain reduction. We present here an evidence-based review of the options for the treatment of neuropathic pain syndromes. Consideration is given to the mechanisms of action, numbers needed to treat (NNT), the recommended doses and the most frequent side-effects of the drugs for which consistent support has been found for treatment of these pain conditions.     

Acute and chronic pain syndromes in multiple sclerosis. A 5-year follow-up study

Forty-nine (22 males, 27 females) patients with definite multiple sclerosis were examined twice with 5 years interval regarding acute (less than 1 month duration) and chronic (more than 1 month duration) pain syndromes. From the first to the second examination a significant increase was found in the number of acute and chronic pain syndromes, including tension and pain in the extremities, spasms, low back pain, Lhermitte's sign and neuralgia. The increase included both men and women. The increase was especially found in patients with deterioration of disability.The study has been supported financially by a number of funds through the Danish Multiple Sclerosis Society, Fonden for Sclerose-ramte paa Fyn and Bikubenfonden. The study has been presented at the XVth World Congress of Neurology, Vancouver, B.C., Canada, September 5–10th 1993.