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This case report elucidates pitfalls of clinical and radiologic investigations of neuropathic pain due to trigeminal pathology, and utility of neurophysiologic examination when diagnosing facial pain. Our patient was a 63-year-old woman who developed acute, severe facial pain, first located behind the left eye. Neuralgic exacerbations, paresthesia within lower face on the left and restricted mouth opening occurred during the course of the disease with gradual progression. Brain MRI and CT scans were interpreted as normal at 4 and 10 months after symptom onset. At 9 months, detailed neurophysiologic examination showed severe chronic mandibular neuropathy at the left oval foramen with more prominent disturbance of the thick myelinated nerve fibers than the small fibers suggesting compressive etiology. Guided by the neurophysiologic findings, 11 months after the onset of the symptoms, a new brain MRI with contrast enhancement revealed metastatic adenocarcinoma of the left temporal bone along the mandibular nerve, exactly matching the site indicated by the neurophysiologic examination. Neurophysiologic tests offer cost-effective, sensitive tools for screening and accurate level diagnostics of neuropathy and neuropathic pain, which can be utilized also in the diagnosis of facial pain. In addition, whenever there are progressing neurologic deficits or neurophysiologic signs indicating expansive lesion, despite initially normal findings in the brain imaging studies, repeated MRI examinations are warranted, preferably focusing to the ‘neurophysiologic region of interest’ to avoid radiologic sampling errors. As no isolated technique achieves 100% diagnostic accuracy, only rational combinations of different methods will result in correct diagnosis of facial pain without unnecessary delays. Treatment of neuropathic pain is often delayed because of difficulties in reaching the correct diagnosis. During the work-up, many differential diagnostic alternatives have to be considered, also in patients with chronic orofacial pain. Table 1 shows the most important differential diagnoses of orofacial pain.

Many conditions associated with chronic pain have no detectable morphological correlate. Consequently, the source of pain cannot be established by clinical examination or medical imaging. However, for some such conditions, the source of pain can be established using diagnostic blocks. The aim of this paper is to review the available evidence concerning the validity and utility of diagnostic blocks, and to identify areas where research is needed. Diagnostic blocks for cervical and lumbar zygapophysial joint pain have been extensively studied. Single blocks are associated with about 30% false-positive responses. Patients can report relief of pain for reasons other than the effect of a local anaesthetic injected during a diagnostic block, e.g. as the result of placebo effect. Therefore, in order to be valid, diagnostic blocks must be controlled in each patient. Many practitioners find limitations in the clinical applicability of placebo-controlled blocks. Comparative blocks (comparison lidocaine-bupivacaine for each block within each patient) have been investigated as alternatives to placebo-controlled blocks. A positive response requires short-lasting relief when lidocaine is used, and long-lasting relief when bupivacaine is used. The validity of comparative blocks is high when the disease under investigation is common. This is the case for zygapophysial joint pain after whiplash injury. However, the validity of comparative blocks strongly decreases with decreasing prevalence of the condition. This is the case for lumbar zygapophysial joint pain in young subjects: in these patients, the expected false-positive rate with comparative blocks is unacceptably high. Diagnostic blocks for cervical and lumbar zygapophysial joint have therapeutic utility. When positive, radiofrequency denervation is expected to produce substantial pain relief in 60-80% of patients. For all other types of blocks, very little research has been conducted. The few studies that have been published did not use controlled blocks. This may have produced a high rate of false-positive responses. Some data on spinal nerve root blocks suggest that these procedures may be valid for the diagnosis of radicular pain and are perhaps predictive for the success of surgery. The validity of diagnostic sympathetic blocks and their prognostic value in relation to outcomes of sympathectomy are unclear. There is lack of data on the validity of diagnostic intra-articular blocks. Discogenic pain is typically diagnosed by provocative discography, but this procedure remains controversial. Intradiscal and sinuvertebral nerve blocks with local anaesthetics are possible alternatives to provocation discography. At present, the sparse data available on these procedures do not allow an estimation of their validity. In conclusion, nerve blocks have an important potential role in the management of chronic pain. These procedures are not suitable to identify the pathology that is the cause of the pain (e.g. inflammatory, neuropathic, etc.). However, they can reveal the anatomical source of pain, thereby allowing the development of targeted treatments. Unfortunately, there is currently very little research on the validity and prognostic value of blocks. The potential usefulness of this practice remains therefore largely unexplored.

Background and aims of the study The connection between chronic pain and traumatic experiences in childhood has been established in several studies. The association of emotional maltreatment with chronic pain has been studied, but to a lesser degree. Schema therapy [24] is an extension of cognitive therapy and presents the early maladaptive schema (EMS) concept. EMSs reflect early, mainly emotional maltreatment. The aim of the present study was to examine the existence of EMSs, the association between EMSs and pain variables and EMS driven patterns. Patients and measures The study consisted of 271 first visit pain patients. Their socio-demographic data, pain variables and pain disability were assessed. The presence of EMSs was measured using the Young Schema Questionnaire Short Form Extended. One hundred and three successive participants were also interviewed according to the cognitive case conceptualization. Results More than half (58.3%) of the chronic pain patients scored EMSs as meaningful. The patients with meaningful EMSs had significantly higher pain intensity, duration of pain and pain disability. The two most frequently occurring EMSs in male pain patients were Unrelenting Standards/Hypercriticalness (US) (36.2%) and Self-Sacrifice (SS) (23.6%) and in female pain patients SS (40.3%) and US (27.1%). The speech contents of five of the highest scoring US and SS male and female patients ( n = 20) were analyzed. The analyses showed schema driven behavior which exacerbated the pain situation. US and SS schemas had a stronger motivational effect on their behavior than the pain itself. Regression analyses showed that Self-Sacrifice schema in women and Emotional Deprivation schema in the total sample predicted pain disability as did pain intensity and the number of pain locations. Conclusions This study suggested that a remarkable amount of chronic pain patients may suffer from early maladaptive schemas which have an effect on their current pain situation and may reflect underlying early emotional maltreatment.

Background Anewexperimental protocol of electrically induced pain and hyperalgesia was established to examine orally administered drugs. In a randomized, double-blind, placebo-controlled cross-over study this experimental protocol was used to assess the effects of paracetamol. Methods Twenty-four subjects were enrolled in this study. The magnitude of pain, axon reflex flare, and areas of pin-prick hyperalgesia and touch-evoked allodynia were assessed in two consecutive sessions; prior to, and 2 h after drug administration. This protocol was repeated after 1 week. Subjects were randomized to receive either paracetamol (2 g) or a placebo. Results In comparison to the placebo arm there were no significant effects of paracetamol on pain, hyperalgesia, allodynia, or axon reflex flare. Pain and flare responses were highly reproducible on the same day ( r = 0.77 and r = 0.79, respectively), and after 1 week ( r = 0.6 and r = 0.71, respectively). The correlation between areas of hyperalgesia and allodynia was, however, significantly improved when the protocol was repeated on the same day ( r = 0.8 and r = 0.75), as opposed to after a week ( r = 0.54 and r = 0.53). Discussion The electrical pain model is a well established method for the assessment of intravenously applied analgesics. In order to assess effects of orally applied drugs the model had to be modified: for the assessment of hyperalgesia and allodynia a protocol repeating the model within 1 day proved to have advantages over repetition after 1 week.

Background and aims Social factors and social environment shape the pain behavior of patients. Social workers support pain treatment in a multidisciplinary pain clinic by altering the social environment of a patient. Even though a social worker in a multi-professional care team contributes to the care of select, severely pain-afflicted patients extensively, neither the patient socio-demographic status nor interventions by social workers have been systematically documented. Only individual case histories have been published. Developing social work activities, which have potential financial consequences, for example, requires charting the current situation prior to systematic research into the efficacy of individual social work interventions. Methods This study systematically details the performance and work volume of the social worker, as well as the socio-demographics of patients during a 16-month period in a multidisciplinary pain clinic of a university hospital. Results Fifty-five patients were included. Twenty-nine were women and 26 men. They were about 10% of all patients seen at the pain clinic during the same time. Most of the patients were at their middle age. The largest group of subjects worked in public or other services. The second largest group consisted of those working in stores, hotels and restaurants. Over half of the subjects worked in the service industry. Since the subjects had scant vocational education, they worked mainly in manual labor. Most of the patients had problems with making a living, signifying that a major number of the patients visited the social worker because of financial problems. About half of the patients were indebt and three were undergoing debt counseling. Of homeowners, 21% were indebt, while the portion of those living rented accommodation was almost two thirds. All patients seen by the social worker received some form of public assistance. Over half of the patients had participated in rehabilitation assessment. The social worker saw 39 patients once, one patient twice and 15 patients three or more times. The duration of a visit was typically 1–2 h. The issues of a patient are addressed by contacting authorities and negotiating with other health care staff. According to the used ‘SOSU’ classification data, the social situation was charted for 49 patients, while the benefits and assistance provided by the Social Insurance Institution of Finland was discussed with half of the patients. The social worker discussed employment based pension with about a third of the patients. Social assistance, the last-resort economic assistance under social welfare, was considered with one fifth of the patients. Psychosocial work was recorded for 19 patients, comprising longer-term, supportive discussion. Conclusions The majority of the patients is of active working age but their working capacity is often decreased. However, they have difficulties in getting compensation for reduced ability to making a living. Hence, they have economic difficulties of various types and need counselling and support. The main duty of the social worker appeared to be advising the patient in using the social welfare system, as the clients turned out to constitute a marginalized group.

Background and aims As far as we know, the range of issues particular to social work, when working with clients at a pain clinic has not been previously researched. Methods A retrospective study of referrals at the multidisciplinary Pain Clinic of Helsinki University Central Hospital was conducted based on medical records, focusing on pain conditions, treatments and patient flow. Variables used were age, gender, pain conditions, treatment interventions, pain duration and intensity, disruption in everyday life due to pain, psychiatric co-morbidities, referrals, outside care providers, post-treatment care and health habits. Referrals were made mainly by other HUCH units or municipal health centers. Results The median age of patients ( n = 55) was 44 years. The majority of patients were referred to the pain clinic by municipal health centers. Almost similar number of patients was referred by other HUCH clinics. The largest disease group was musculoskeletal diseases, afflicting 25 patients. Almost the same number of patients (22) suffered from neurological and sensory nervous system diseases. Three patients suffered from persistent somatoform pain disorder and five patients did not fall into any of these categories. Pharmacotherapy was the most prevalent treatment method at the pain clinic, and it was prescribed to all patients. The post-treatment care of the patients was mainly provided by primary health care services. Duration of pain was more than 3 years in more than 60% of the patients. There was a considerable lack of information about pain intensity in the patient files. For the majority of patients, pain caused difficulty in movement, housework, recreation, and sleeping. Patients referred to the pain clinic's social worker had not benefited greatly from previous interventions. More than half of the patients had received psychiatric consultation either at the pain clinic or in some other setting. Most often the patients had been diagnosed to suffer from depression by a psychiatrist. Over a third of the patients had reported suicidal intents to the hospital staff. Conclusions The pain situation of patients was severe, in terms of intensity and disability. Treatment was primarily based on drug therapy, and patients generally continued treatment in outpatient services. Depression and substance abuse were common; a third had experienced suicidal intent. By searching for symptoms, the social worker pays attention to signs of depression at the clinic. Co-operation with social workers in outpatient services is also critical for social after-care. This requires that the social worker of a pain center has an excellent and practical knowledge of the social welfare and service systems.

Background Evidence for a role of immune system in hyperalgesic pain states is increasing. Recent work in neuroimmunology suggests that the immune system does more than simply perform its well known functions of recognizing and removing invading pathogens and tumors. Interest in neuroinflammation and neuroimmune activation has grown rapidly in recent years with the recognition of the role of central nervous system inflammatiom and immune responses in the aetiology of pain states. Among various theories, the role of inflammatory responses of the injured nerve has recently received attention. Cytokines are heterogenous group of polypeptides that activate the immune system and mediate inflammatory responses, acting on a variety of tissue, including the peripheral and central nervous system. Interleukin-6 (IL-6) a pro-inflammatory cytokine, is potentially important in pain aetiology, have pronociceptive actions. Neuropathic pain may be due to a primary insult to the peripheral or central nervous system. Substances released during inflammation from immune cells play an important role in the development and maintenance of chronic pain. Nimesulide, a highly selective cox-2 inhibitor, effectively reduces hyperalgesia due to peripherally administration of inflammatory agents like formalin. The safety of nimesulide was reported for some conditions in which other NSAIDs are contraindicated. Here we have determined the effect of nimesulide on pain behaviour and serum IL-6 level in chronic constriction injury (CCI) model of neuropathic pain. Methods Experiments were carried out on male Wistar rats, (weight 150–200 g, n = 8). Rats were divided into 3 different groups: 1-CCI + saline 0.9% 2Sham + saline 0.9% (control) 3CCI + drug. Nimesulide (1.25, 2.5, 5 mg/kg, i.p.) was injected 1h before surgery and continued daily to day 14 post-ligation. 42 °C water for thermal hyperalgesia, von Frey filaments for mechanical allodynia, acetone test for cool allodynia and 10 °C water for cold hyperalgesia were respectively used as pain behavioural tests. Behavioural tests were recorded before surgery and on postoperative days 1, 3, 5, 7, 10, 14 and the serum concentration of IL-6 was determined at the day 14. Results The results of this study showed a decrease in hyperalgesia and allodynia following nimesulide administration. Conclusions It appears that nimesulide was able to reduce pain behaviour due to nerve inflammation and a parallel decrease in the serum IL-6 concentration was observed. Implications The immune system is an important mediator in the cascade of events that ultimately results in hyperalgesia. Cytokines contribute to the patheogenesis of neuropathic pain, therefore drugs that inhibit cytokine release from immune cells may reduce inflammatory pain states.