Harald Breivik

Survey of chronic pain in Europe: prevalence, impact on daily life, and treatment.

This large scale computer‐assisted telephone survey was undertaken to explore the prevalence, severity, treatment and impact of chronic pain in 15 European countries and Israel. Screening interviews identified respondents aged ≥18 years with chronic pain for in‐depth interviews. 19% of 46,394 respondents willing to participate (refusal rate 46%) had suffered pain for ≥6 months, had experienced pain in the last month and several times during the last week. Their pain intensity was ≥5 on a 10‐point Numeric Rating Scale (NRS) (1 = no pain, 10 = worst pain imaginable) during last episode of pain. In‐depth interviews with 4839 respondents with chronic pain (about 300 per country) showed: 66% had moderate pain (NRS = 5–7), 34% had severe pain (NRS = 8–10), 46% had constant pain, 54% had intermittent pain. 59% had suffered with pain for two to 15 years, 21% had been diagnosed with depression because of their pain, 61% were less able or unable to work outside the home, 19% had lost their job and 13% had changed jobs because of their pain. 60% visited their doctor about their pain 2–9 times in the last six months. Only 2% were currently treated by a pain management specialist. One‐third of the chronic pain sufferers were currently not being treated. Two‐thirds used non‐medication treatments, e.g,. massage (30%), physical therapy (21%), acupuncture (13%). Almost half were taking non‐prescription analgesics; ‘over the counter’ (OTC) NSAIDs (55%), paracetamol (43%), weak opioids (13%). Two‐thirds were taking prescription medicines: NSAIDs (44%), weak opioids (23%), paracetamol (18%), COX‐2 inhibitors (1‐36%), and strong opioids (5%). Forty percent had inadequate management of their pain. Interesting differences between countries were observed, possibly reflecting differences in cultural background and local traditions in managing chronic pain. Conclusions: Chronic pain of moderate to severe intensity occurs in 19% of adult Europeans, seriously affecting the quality of their social and working lives. Very few were managed by pain specialists and nearly half received inadequate pain management. Although differences were observed between the 16 countries, we have documented that chronic pain is a major health care problem in Europe that needs to be taken more seriously.

International Association for the Study of Pain: update on WHO-IASP activities.

The International Association for the Study of Pain (IASP), founded in 1972, is a non-governmental organization (NGO) and has an official relationship with the World Health Organization (WHO). IASP and individual IASP members have collaborated with WHO for more than two decades in improved understanding of pain and promoting better availability of pain therapy world wide. The first WHOIASP liaison-officer was Dr. Kathleen Foley. She has had a major impact on the WHO cancer pain and palliative care programs and was one of the driving forces for the expert groups that developed WHO publications and educational resources, such as the booklet WHO Cancer Pain Relief, published in 1986. 1–4

Assessment of pain

UNLABELLED Valid and reliable assessment of pain is essential for both clinical trials and effective pain management. The nature of pain makes objective measurement impossible. Acute pain can be reliably assessed, both at rest (important for comfort) and during movement (important for function and risk of postoperative complications), with one-dimensional tools such as numeric rating scales or visual analogue scales. Both these are more powerful in detecting changes in pain intensity than a verbal categorical rating scale. In acute pain trials, assessment of baseline pain must ensure sufficient pain intensity for the trial to detect meaningful treatment effects. Chronic pain assessment and its impact on physical, emotional, and social functions require multidimensional qualitative tools and health-related quality of life instruments. Several disease- and patient-specific functional scales are useful, such as the Western Ontario and MacMaster Universities for osteoarthritis, and several neuropathic pain screening tools. The Initiative on METHODS Measurement, and Pain Assessment in Clinical Trials recommendations for outcome measurements of chronic pain trials are also useful for routine assessment. Cancer pain assessment is complicated by a number of other bodily and mental symptoms such as fatigue and depression, all affecting quality of life. It is noteworthy that quality of life reported by chronic pain patients can be as much affected as that of terminal cancer patients. Any assessment of pain must take into account other factors, such as cognitive impairment or dementia, and assessment tools validated in the specific patient groups being studied.

Mapping of punctuate hyperalgesia around a surgical incision demonstrates that ketamine is a powerful suppressor of central sensitization to pain following surgery

Background: Tissue injury induces central sensitization in the spinal cord dorsal horn neurons via mechanisms involving N‐methyl‐D‐aspartate (NMDA) receptors, leading to secondary hyperalgesia. Using punctuate mechanical hyperalgesia as a measure of central sensitization, we examined whether induction and maintenance of central sensitization after surgery could be prevented by a low‐dose infusion of the NMDA‐receptor antagonist ketamine.

Relief of post-herpetic neuralgia with the N-methyl-D-aspartic acid receptor antagonist ketamine: a double-blind, cross-over comparison with morphine and placebo.

&NA; Pain and sensory thresholds were examined before and after intravenous administration of ketamine (0.15 mg/kg), morphine (0.075 mg/kg) or saline in 8 patients with post‐herpetic neuralgia. A randomized, double‐blind, cross‐over study design was used. Post‐herpetic neuralgia was associated with impaired sensory function, as shown by reduced tactile and warm sensation in the affected compared with the contralateral non‐affected skin area. Neither ketamine nor morphine changed significantly the thresholds for warm, cold, heat pain or tactile sensation. However, ketamine normalized abnormal heat pain sensations in 4 patients, probably due to a central effect. Ketamine, but not morphine, produced significant relief of pain. Pain evoked by non‐noxious stimulation of the skin (allodynia) was significantly inhibited by ketamine as well as by morphine. Wind‐up‐like pain (i.e., pain evoked by repeatedly pricking the affected skin area) was significantly inhibited by ketamine, but significantly aggravated by morphine. Side effects were observed in all the 8 patients after injection of ketamine and in 6 patients after injection of morphine. The present results support the hypothesis that the Symbol (NMDA) receptors are involved in the control of post‐herpetic neuralgia including allodynia and wind‐up‐like pain. The NMDA receptors also may play a role in the modulation of thermal perception. Symbol. No caption available

Cancer-related pain: a pan-European survey of prevalence, treatment, and patient attitudes

BACKGROUND The European Pain in Cancer survey sought to increase understanding of cancer-related pain and treatment across Europe. PATIENTS AND METHODS Patients with all stages of cancer participated in a two-phase telephone survey conducted in 11 European countries and Israel in 2006-2007. The survey screened for patients experiencing pain at least weekly, then randomly selected adult patients with pain of at least moderate intensity occurring several times per week for the last month completed a detailed attitudinal questionnaire. RESULTS Of 5084 adult patients contacted, 56% suffered moderate-to-severe pain at least monthly. Of 573 patients randomly selected for the second survey phase, 77% were receiving prescription-only analgesics, with 41% taking strong opioids either alone or with other drugs for cancer-related pain. Of those prescribed analgesics, 63% experienced breakthrough pain. In all, 69% reported pain-related difficulties with everyday activities; however, 50% believed that their quality of life was not considered a priority in their overall care by their health care professional. CONCLUSIONS Across Europe and Israel, treatment of cancer pain is suboptimal. Pain and pain relief should be considered integral to the diagnosis and treatment of cancer; management guidelines should be revised to improve pain control in patients with cancer.

Continuous subcutaneous administration of the N-methyl-D-aspartic acid (NMDA) receptor antagonist ketamine in the treatment of post-herpetic neuralgia.

&NA; The effect of continuous subcutaneous (s.c.) infusion of ketamine on nerve injury pain was examined in patients with post‐herpetic neuralgia. Five patients that reported pain relief after acute intravenous injection of ketamine were included in this open prospective study. Ketamine was administered continuously in increasing doses using a portable infusion pump (CADD‐PLUS, Pharmacia), and the treatment period for each infusion rate (0.05, 0.075, 0.10, or 0.15 mg/kg/h) was 7 days and nights. Relief Of continuous pain, as evaluated daily by visual analogue scales, was observed at the infusion rate of 0.05 mg/kg/h, but was most marked during infusion of 0.15 mg/kg/h. All the patients reported that ketamine reduced the severity of continuous pain as well as reduced the severity and number of attacks of spontaneous pain. Changes in evoked pain (allodynia and wind‐up‐like pain) were recorded before change of infusion rate. Allodynia was maximally reduced 59–100% after 1 week infusion of 0.05 mg/kg/h, and wind‐up‐like pain was maximally reduced 60–100% after 1 week infusion of 0.15 mg/kg/h. Itching and painful indurations at the injection site was the most bothersome side‐effect and for this reason 1 patient discontinued treatment after 2 weeks. Other common side‐effects were nausea, fatigue and dizziness. The present results show that continuous, spontaneous and evoked pain in patients with post‐herpetic neuralgia is reduced by continuous s.c. infusion of ketamine, but is associated with intolerable side effects.

Epidural versus general anaesthesia for total hip arthroplasty in elderly patients.

Sixty elderly patients were given at random either epidural analgesia with bupivacaine 0.75% or general anaesthesia with thiopentone, fentanyl, pancuronium, N2O/O2 for total hip replacement. Preoperatively the patients were of equal physical status with normal and similar laboratory values. All patients were mentally normal for their age. On the 1st postoperative day, the general anaesthesia group had a signilicantly lower PaO2 than the epidural group (p<0.025). Pao2 in the general anaesthesia group was significantly lower than the preoperative value on the 1st and 3rd postoperative days (P<0.001 and P<0.01, respectively). None of the 29 patients in the epidural group but seven of 31 patients in the general anaesthesia group had signscant mental changes postoperatively (p<0. 01). Five of these patients still had mental changes which reduced their quality of life several months later. In the general anaesthesia group, one patient died from an acute myocardial infarction. Low postoperative PaO2 might have contributed to this death. Two patients in the epidural group had symptoms of pulmonary embolism postoperatively. Thus elderly patients appear to do better after hip replacement with less deterioration of cerebral and pulmonary functions when given epidural analgesia than when surgery is performed under general anaesthesia. These patients should therefore be offered epidural analgesia whenever possible.

Epidural Morphine for Postoperative Pain: Experience with 1085 Patients

A prospective study of the effect and side‐effects of epidural morphine for pain relief in 1085 patients after thoracic, abdominal, urologic, or orthopaedic surgery was performed. Morphine chloride was diluted in saline or bupivacaine and administered through an epidural catheter placed at a segmental level appropriate for the type of surgery. The initial dose was 4 or 6 mg morphine and supplementary doses were given when needed to obtain complete freedom from pain during deep breathing or nursing care. The total dose of epidural morphine from end of surgery until the next morning varied from 4 to 18 mg. 97% of hip arthroplasty patients, 91% of prostatectomy patients and thoracotomy patients, 90% of patients after major lower extremity surgery and 88% of patients after laparotomy were completely satisfied with the postoperativr course. For hip arthroplasty and major extremity surgery, an initial dose of 4 mg of epidural morphine was as effective as 6 mg. After prostatectomy, laparotomy, and thoracotomy, an initial dose of 6 mg gave significantly better effect than 4 mg. Pruritus occurred in 11%, nausea or vomiting in 34%, and respiratory depression in 0.9% of the total patient population. Urinary retention occurred in 42% of patients not having urinary catheters in place. Postoperative nausea or vomiting was more frrquent in women than in men (P<0.001). There was a higher incidence of nausea or vomiting in men experiencing pain than in men who were completely pain‐free after abdominal surgery (P<0.001). Respiratory depression was rare and occurred as a gradually decreasing respiratory rate. Treatment with naloxone was effective without pain‐breakthrough. Naloxone relieved pruritus in 9O% of patients in whom it was attempted, but was not effective in treating nausea, vomiting, or urinary retention. After this study our dosage regimen for postoperative epidural morphine is: for major surgery of the lower limb or hip arthroplasty 4 mg; after prostatectomy. laparotomy, and thoracotomy 6 mg. No later than 12 h before the patients leave the postoperative care unit, half the initial dose of epidural morphine is usually repeated. Morphine is diluted in bupivacaine if pain is already present, otherwise in saline.

Breakthrough pain in malignant and non-malignant diseases: a review of prevalence, characteristics and mechanisms.

Breakthrough pain or transient worsening of pain in patients with an ongoing steady pain is a well known feature in cancer pain patients, but it is also seen in non‐malignant pain conditions with involvement of nerves, muscles, bones or viscera. Continuous and intermittent pain seems to be a general feature of these different pain conditions, and this raises the possibility of one or several common mechanisms underlying breakthrough pain in malignant and non‐malignant disorders. Although the mechanisms of spontaneous ongoing pain and intermittent flares of pain (BTP) may be difficult to separate, we suggest that peripheral and/or central sensitization (hyperexcitability) may play a major role in many causes of BTP. Mechanical stimuli (e.g. micro‐fractures) changes in chemical environments and release of tumour growth factors may initiate sensitization both peripherally and centrally. It is suggested that sensitization could be the common denominator of BTP in malignant and non‐malignant pain.