News Category: Pain

Complex regional pain syndrome (CRPS) is a disorder that causes chronic, often severe pain. The syndrome follows a seemingly minor soft tissue injury or fracture.

Up to now, little has been found to help relieve the symptoms patients experience with CRPS: change in tissue blood flow, skin temperature, edema (swelling from fluid), and sweating, among others. Although some analgesics may relieve some pain, some patients do end up having affected limbs amputated.

The authors of this study wanted to see if improving the blood flow to the affected limb would reduce damage that may result in the need for amputation. To do this, researchers recruited five women, average age 49.6 years, to be treated on the affected hand with nitric oxide donor isosorbide dinitrate ointment (ISDN), which would cause dilation (widening) of the blood vessels, allowing for improved blood flow. The ointment was applied four times a day for 10 weeks.

The researchers measured skin temperature, comparing the affected side with the non-affected side, and patients used a weekly diary using the Visual Analog Scale> to rate pain from one to 100, with 100 being the worst possible pain. The pain intensity was assessed with the McGill Pain Questionnaire. Hand and arm strength, and elbow extension were also measured.

At two weeks following the start of the study, the researchers found an increase of approximately 4 degrees Celsius in the affected hand. The muscle force in the elbow remained the same in four patients, but deteriorated in one. Three patients complained of headache during the first two weeks of treatment.

The authors concluded that, although reliability of the study is limited because of the small size (five patients), the treatment does appear to affect body temperature where applied and may prove to be a viable treatment for CRPS.

Complex regional pain syndrome (CRPS) is a little understood syndrome that often occurs after a relatively minor injury or after a trauma like a fracture. The result of CRPS is persistent pain, changes in skin temperature, sweating and swelling. These may also result in dystonia, or abnormal muscle tone, in the affected arm, hand, leg, or foot.

Researchers have had a theory that there may be something in the cerebrospinal fluid that was involved in making biochemical changes, resulting in these affects from the CRPS. A previous study had indicated that there may be elevated IL-1beta and IL-6 in the cerebrospinal fluid, which may be causing part of the problem. This study was undertaken to see if the results would be the same in a second similar study.

To perform the analysis on the cerebrospinal fluid, the researchers obtained samples from 20 patients who had participated in an earlier study and 29 controls who had had spinal anesthesia for non-CRPS related surgical interventions. The researchers were unable to reproduce the findings of the first study. No differences were found in the samples from both the patients with CRPS and those without.

Determining pain levels in patients is not an easy task since pain is such a subjective sensation. In verbal patients, they can be asked to rate their scale from 0 to 10 and to describe the intensity. Non-verbal patients, particularly the elderly who may also have dementia, are not as able to express the quality and quantity of pain.

The authors of this article developed a non-verbal pain scale, the Elderly Pain Caring Assessment (EPCA-2). The 8-item scale based on patient behaviors is meant to be used in day-to-day practice by healthcare professionals, particularly nurses.

To develop the scale, the authors recruited patients 340 patients who were 65 years or older (mean age: 79.4 years) and unable to verbally communicate complaints of pain. The diagnosis included bedsores (78 patients), cancer (74), dementia (68), stroke (54), other neuropathy (20), arthritis (26), or bone fracture (30). One hundred twelve patients were taking opioids, 171 were taking non-opioids, and 57 were taking non-analgesics. Eight criteria were established for observation by caregivers.

Before treatment to manage pain:

1- Facial expression
2- Spontaneous posture adapted at rest
3- Movements of the patient in and out of bed
4- Interaction of all kinds with other people

During intervention by the caregiver:

5- If the patient has an anxious reaction to the intervention
6- Reactions during the intervention
7- Reactions when the painful parts of the body are attended to
8- Complaints during intervention.

Each assessment had a scale of 0 to 4 for rating patient reaction.

The authors wrote that the raters (nurses, caregivers, and doctors) felt the structure of the assessment was sound and valid, with an inter-rater reliability being very good. The consistency was also rated as highly satisfactory.

In conclusion, the authors state, “After a short training session, EPCA-2 may provide nurses, caregivers, and doctors with a good instrument for pain assessment in NVC older patients.”

A questionnaire by researcher C.R. Cloninger and colleagues is useful in clinical practice to detect personality disorders (PDs) among patients who are experiencing chronic pain. The questionnaire, called the Temperamental and Character Inventory, identifies traits such as harm avoidance, novelty seeking reward dependence, persistence, self-directedness, cooperativeness, and self-transcendence.

It has long been thought that certain personality traits could affect how patients react to pain and pain treatment. The authors of this study wanted to compare the personality profiles of patients with chronic pain (CPP) with patients who do not have chronic pain; they also wanted to see whether the TCI questionnaire could predict the personality disorders and the different subtypes within. To do this, researchers recruited 207 patients who attended a local pain clinic. The majority of patients complained of back and leg pain (72 percent), followed by neck and arm pain (13 percent), abdominal pain (3 percent) and other sites (12 percent). One hundred seven pain-free controls also participated.

Pain in the CPP group was assessed through a variety of tools, including the German version of the Brief Pain Inventory, the Temperament and Character Inventory, the German version of the Beck Depression Inventory, the German version of the State-Trait-Anxiety Inventory, the Mini-International Plus, and the Standard Clinical Interview for DSM-IV Personality Disorders.

When analyzing all the data, the researchers found that a high Harm Avoidance in CPPs was an important part of forming the emotional core of personality. Earlier studies have shown that the fear of pain and the associated behavior can be more disturbing and disabling than pain itself. The researchers also note the important finding among CPPs is the low scores on self-directedness and cooperativeness, which represent the cognitive core. This gives people a feeling that they can control or positively influence unpleasant situations or that they can solve a problem. In fact, along with the other issues found by the questionnaires and tests, the study findings showed that 41 percent of CPPs had at least one personality disorder, which is relevant to issue of chronic pain as this can negatively affect the outcome of pain management.

Broken down, the findings were as follows: “TCI predicted an average of 23 percent in PD symptom counts, the Self-directedness and cooperative personality traits appeared to be significant predictors in determining the presence or absence of a PD by correctly classifying 75.8 percent of CPPs.”

The authors conclude that knowing about these issues can help identify that there is a relationship between the neurobiological basis of the relationship between specific personality traits and treating chronic pain. By knowing this, future studies could look at the usefulness of discovering such traits in planning pain treatment plans.

Chronic neuropathic pain is mainly treated with medications. These include antidepressants, antiepileptics, opioids, and topical local anaesthetics. Sometimes better pain relief is needed. Cannabinoids are known to have analgesic properties. The authors of the study evaluated the effect of a medication called Sativex. Sativex is made from selected strains of cannabis plants. It contains a combination of delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) in a spray form. The spray is used under the tongue or inside the cheek. Cannabinoids are thought to work at two types of receptors. CBD was used as combining it with THC is thought to lead to an increase in desired effects such as analgesia and sedation as well as decrease unwanted side effects.

125 subjects with neuropathic pain of peripheral origin were included in the study. 63 recieved the Sativex and 62 were on placebo. The authors wanted to study the medication effect on severity of pain, allodynia, sleep disturbance, mental distress and disability. The study lasted five weeks. They subjects were allowed to titrate the medication as they desired after the first seven to ten days. During this time, the number of sprays were limited and signs and symptoms of intoxication were monitored.

The improvement in pain over placebo was evident from the second week after titration until the end of the five week trial. 26 percent of the Sativex group reported greater than 30 percent improvement in pain compared to 15 percent of the placebo group. Improvenent in sleep, allodynia, and disability were also significantly improved over the placebo group. Doses remained stable after the two week titration period. The participants that chose to continue the study for up to 52 weeks did not need to significantly increase the number of sprays per day used.

Most common adverse side effects in the subjects using Sativex included nausea, vomiting, diarrhea, and constipaton. Another subject experienced paranoid thinking. 18 percent of the Sativex subjects withdrew from the study because of adverse events compared to three percent in the placebo group.

The authors concluded that Sativex has a positive effect in neuropathic pain. However, side effects, particularly involving the gastrointestinal tract may limit its use in some individuals.

The authors of the study interviewed 27 participants who had been diagnosed with Complex Regional Pain Syndrome. Pain in a limb is the main symptom in CRPS. Patients with CRPS have been noted to neglect their affected limb, rather than being overattentive, or protective of the limb as might be expected. CRPS has been described as having neurological neglect-like symptoms similar to some people after having a stroke. The authors proposed that this might not be an accurate description, but that body perception disturbance more accurately described the phenomenon.

The authors explored participants’ feelings and perceptions about their affected body parts. They hoped the participants would describe their perceptions about the affected limb both physically and emotionally. Pain, depression, and general health status were measured with the commonly used Brief Pain Inventory, the Beck Depression Inventory, and the SF-36. The small sample of participants were noted to have moderate pain intensity, were physically limited, and had mild to moderate depression ratings.

Pain was described in several common themes. These were hostile feelings, disassociation of the limb, and disparity between what is visually apparent and what is felt. Other themes included, distorted mental images of the affected part, and conscious attention.

Feelings of hostility ranged from mild frustration to more intense experiences such as hate, disgust, and repulsion of the affected part. Disassociation was described as psychological detachment of the affected limb from the remainder of their unaffected body. Some even desired getting rid of the pain by amputation of the affected limb. Many participants reported that the affected limb looked differently than it felt. Feelings of size, pain, and temperature varied with the way the limb actually looked. Mental pictures of the affected limb were distorted in comparison to their unaffected opposite limb, but only certain parts of the limb, not the whole limb. While participants reported their awareness of the affected limb was heightened due to the pain, they typically had difficulty in knowing its position. Some participants avoided looking or touching their affected limb. In some cases they hid the limb from their field of view. Others touched their limb routinely to check it. Others had to concentrate on their limb to move it.

Those with mild disease described fewer disturbances than those with more severe disease. Reduced body perception disturbance appeared to decrease symptoms, particularly pain.

In CRPS, there seems to be a complex interaction between pain, disturbances in body perception and central remapping in the brain. Brain imaging studies confirm this. These findings may support the use of treatments that target cortical areas of the brain to reduce body perception disturbances and therefore pain in CRPS.

The fear of addiction is often listed as a compelling reason to limit prescriptions of opioids. However, many doctors list insufficient knowledge of prescribing practice of opioids as a reason for limiting prescriptions.

Persistent noncancer pain (PNCP) is caused by many illnesses or disorders and can become quite disabling, affecting quality of life and other health issues. The authors of this study investigated prescribing practices of 132 physicians to identify the differing attitudes in prescribing opioids for noncancer pain.

A 26-item questionnaire was completed by the physicians. Among the group, 67 percent were house staff physicians and 33 percent were attending-level physicians. Internists made up the majority of the group (79 percent), the rest were geriatricians.

The questionnaire evaluated the physicians’ knowledge of opioids and their use, and any barriers to prescribing them. The researchers found that about one quarter of all the physicians were hesitant to prescribe opioids because they were not sure of the proper dosages. The physicians most comfortable with the dosing were the geriatricians. A little more than half (58 percent) of physicians were concerned about side effects and this was for both internists and geriatricians.

Illegal diversion of the opioids was a concern for 31 percent of the physicians, although the geriatricians were less inclined to be concerned with this aspect. Finally, the prospect of being scrutinized for opioid prescription was a factor for about 20 percent of the physicians, particularly those who were house physicians.

When asked about their beliefs about chronic pain, almost all (90 percent) did agree that regular opioid use is the preferred method of pain relief. Patients were also often afraid of asking for pain relief for fear of addition (reported by 78 percent of the physicians). While more than half (57 percent) of the physicians felt that patients who had chronic pain would need more medications at higher doses than would patients with acute pain, 16 percent felt that there was a risk of the patient with chronic pain becoming addicted. In fact, 8 percent of the physicians stated that increasing opioid doses were an indication that the patient was becoming addicted to the medications.

Side effects of opioids can be serious and while geriatricians did not agree strongly, one third of the doctors in total felt that sedation is a common side effect of opioids.

The researchers pointed out that there were some significant differences between the prescription thoughts and practices of the internist and the geriatrician. While the internists had concerns about not being adequately knowledgeable about the correct dosages, illegal diversions, and addictions, the geriatricians were more concerned with not managing the pain properly due to under-reporting of pain by the patient.

The authors pointed out the limitations to the study included the small study size and that the study was done only at one institution. They concluded, however, that there are differing issues among the internists and geriatricians that should be addressed in order to better treat the patients with chronic noncancer pain.

Complementary and alternative medicine (CAM) is the use of nontraditional means of healing. This could range from massage to acupuncture to hypnosis. In this study, use of CAM was compared between two groups of arthritis sufferers living in the Chicago area.

Patients from North Chicago (primarily white or Caucasian) were compared to patients from the South Chicago (African Americans) area. All reported chronic joint symptoms.

These two groups are very different in race, culture, and basic demographics. Demographics refer to social characteristics such as age, marital status, and education or income level.

The North Chicago area involved with this study was mostly an upper middle class white group. The South Chicago area group was lower to middle income African Americans. Both groups had a small number of Hispanic/Latino residents.

A telephone interview was conducted to survey use and satisfaction with seven different types of CAM. Categories of CAM included nutritional supplements, vitamins, or herbal therapies. Relaxation techniques, massage, and meditation were also included. Additional groups of CAM included biofeedback, acupuncture, and chiropractic care.

Over half of all patients in both groups reported using CAM for their arthritis. About 20 per cent used two or more CAM therapies. Patients from South Chicago had more arthritis severe enough to limit activity. They were more likely to be taking prescription drugs for their joint pain. And they were more likely to miss work due to joint symptoms.

The most commonly used CAM methods were nutritional supplements, vitamins, or herbal therapies and massage or other relaxation techniques. Adults with education beyond high school were 15 times more likely to use acupuncture, chiropractic care, or naprapathy. Naprapathy is the manipulation of connective tissue.

Overall, it appeared that African Americans with severe arthritis symptoms living in South Chicago were most likely to use CAM. The use of CAM doesn’t have so much to do with demographics as it does the intensity of joint pain.

The commentary provided by the primary author of this report suggests that there is a need for reappraisal of opioid use in chronic, non-cancer pain. The pendulum may have swung from “opiophobia” in the 1950’s to today’s apparent “opiophilia”. However, while some patients are on very high doses of opioids with little or questionable benefit, there are a greater number of patients who have not been prescribed any opioids despite serious physical pathology.

There seems to be many problems with opioid prescribing-overuse, abuse, misuse, diversion, underuse and opioid over-prescribing.

Since providers have been prescribing opioids for chronic, non-cancer pain, the Drug Abuse Warning Network has documented a seven-fold increase in Emergency Department visits and overdose deaths related to oxycodone alone. Other studies have shown that the rate of prescription opioid abuse has exceeded the rate of heroin use.

While opioids may be quite useful for moderate to severe pain, the mean decrease in pain intensity in most studies is 30 per cent.

Physicians have to navigate between the extremes of no prescribing versus excessive prescribing by prescribing opioids when indicated. They must learn to identify and manage opioid misuse and addiction, and avoid prescribing excessive doses.

In general, opioids are not considered to have a dose range and ceiling. It is also believed that high doses can be safely titrated. These commonly held beliefs are only partially supported by evidence. The analgesic effects of high opioid doses are limited by the development of hyperalgesia and analgesic tolerance. Cognitive impairment is another concern but the authors concluded that studies have not been adequate.

Abuse-deterrent formulations may be key in the control of prescription opioid abuse. They make it more difficult or impossible for patients to extract the opioid by crushing, biting, snorting or injecting it. This will reduce the risk of addiction and street value of opioids. Their utility will be influenced by cost, availability, and acceptance by physicians and patients. Perhaps their greatest value is that they will reassure physicians and the public that opioids can be prescribed safely without undue fear of addiction.

Thirty five to 57 per cent of people in the United States are using Complementary Alternative Medicine (CAM) of one sort or another. CAM is defined as a group of medical and healthcare systems, practices, and products that currently are not considered part of conventional medicine. These include therapies such as dietary supplements, herbs, mega-vitamins, homeopathic medicines, acupuncture, etc. Studies have also shown that over half of people using CAM do not inform their doctor(s).

The authors in this study chose to explore use of CAM in fracture patients. Because CAMS can interfere with anesthesia, or cause other complications during surgery such as bleeding, it is important for patients with fracture to disclose their CAM use to their orthopedic surgeon. It is important in managing them in the hospital and fracture clinic.

For example, chondroitin, gingko biloba, ginseng, and garlic supplements may lead to an increase in bleeding so should be stopped before surgery. Echinacea should be stopped two to three weeks before surgery. It can slow the clearance of certain medications. It may also affect allergic reactions, and cause suppression of the immune system. This could affect healing and fighting infection. Glucosamine should also be stopped two to three weeks prior to surgery as it may cause low blood sugar, fainting, and delayed recovery after anesthesia.

It is not clear which CAMS positively affect bone healing and just how much. Most studies have been done in the laboratory, not in humans. Laboratory studies suggest that Omega-3 fatty acids may help heal cartilage and bone. Black cohosh may stimulate cells that make new bone. Aloe vera may prevent arthritis and help bone growth. In animals, chrondroitin may help healing of bone. Boron may also help with bone healing.

Similar to other studies of the general population, 35 percent of the participants with fractures that were surveyed were using some form of CAM. Also similar to the general population of persons using CAM, 55 percent of the participants in the study had not informed or did not intend to inform their orthopedic surgeon of their CAM use. Participants responded that they did not feel it was important enough to discuss. Others felt the surgeon would not approve, or would not know a lot about CAMs.

This lack of communication can be problematic. Othopedic surgeons should be aware of CAMs and potential interactions, and the potential for impairment of fracture healing. For optimal safety and outcome, patients should disclose CAM use with their orthopedic surgeon upon initial evaluation.

In this editorial, pain researchers give their thoughts and opinions on the fact that people with chronic pain often have pain in more than one area. Suggestions for future research to understand this phenomenon are also offered.

Most people go to the doctor with more than one symptom at a time. Perhaps this is because they wait until the problem gets worse and presents with more than one symptom. Or perhaps, as in the case of pain, it’s just more likely that pain occurs in more than one place at a time.

There are many theories about why most pain is multiple. Scientists are trying to find specific links to explain this problem. Researchers are also looking for risk factors that could be modified or prevented.

Some risk factors might include occupational activity. For example, a work-related task involving the whole body can produce back, neck, arm, and knee pain. Some diseases such as osteoarthritis can cause joint pain throughout the body.

Mood disorders such as anxiety and depression are also risk factors for multiple pain sites. And there is some evidence that social, cultural, and economic factors are linked with symptoms and severity of symptoms.

More study is needed to sort out which risk factors go with each type of pain and linked pain sites. These authors suggest it makes more sense to figure out why pain occurs in several places at one time than to explain why pain A and B always occur together.

Further study to identify specific links between A and B may be valuable. But it’s likely that answering the first question will answer the second as well.

Addictive painkillers such as opioid analgesics remain in the center of an ongoing debate. Misuse and abuse of such medications has made it difficult for chronic pain patients who really need this management tool to obtain it.

Scientists are trying to develop an abuse-deterrent opioid product. Such a drug would provide the pain relief needed without causing addiction.

But there are many challenges facing this type of research. A two-day meeting to discuss opioid abuse resistance was held in 2005. This report is a summary of experts’ opinion on this topic from those meetings.

Terms used to describe the problem of opioid-addiction such as misuse, abuse, dependence, tolerance, and addiction were defined. The types of opioid abusers and ways to abuse these drugs were also discussed.

For example, opioid use goes beyond pill popping. Some people crush the pills then snort, smoke, or inject the drug. This gives them a faster, more intense high.

The majority of opioid users have a lifetime history of addictions. It’s estimated that only 30 per cent of opioid abusers have a medical need for pain control. Healthcare professionals such as doctors and nurses can also become addicted.

There are many factors to consider when developing an abuse-resistant drug that controls pain. Given the many and different ways people use and abuse drugs, it may not be possible to create one pill that meets all needs.

How can research be done when there are so many different types of people who may use a deterrent product? Can human studies be done without causing opioid abuse? What kind of labeling should go on the products? How will they be marketed and advertised? Will drug abusers be able to find ways to misuse an opioid-deterrent?

These and many other questions were posed and discussed by the experts at this symposium. It is agreed upon that a comprehensive approach is needed to prevent drug abuse. Opioid-deterrent drugs will eventually be a part of the management program. The authors conclude it will be necessary to find ways to set clear standards for the use of such products.

As physicians become more aware of the connection between chronic pain and patient perception, there have been many studies investigating how the link can help relieve chronic pain. It is important to understand this connection because it can lead to better pain control through more targeted treatment, and it can help physicians and researchers better understand the illness or disorder causing the pain.

In this study, researchers wanted to learn whether patients could improve in function after participating in a cognitive awareness program. Recruited from a 4-week group pain management program in New Zealand, 76 patients (49 women) agreed to participate in the study. The average age of participants was 42 years and they experienced an average of 7 years of pain. More than half (57 percent) were unemployed because of the pain. Their participation consisted of completing questionnaires as they went through the program and after its completion. Of the 76 patients who began the study, 64 patients completed questionnaires throughout the program to the end, 58 completed them at 6 months after the program’s end.

The questionnaires were chosen to evaluate overall health, mental and physical, perceptions about illness, and reaction to pain. The Short Form Health Questionnaire or the SF-36, measured the outcome after the study (28 weeks). The SF-36 looked at the mental and physical components, the abilities to perform every day tasks, how the pain was interfering with the patients’ life, and the extent of body pain. The Revised Illness Perceptions Questionnaire, or IRQ-R, measured how the patients represented their pain: negative representations, timelines, and emotional distress. The Pain Catastrophizing Scale measured the tendencies of patients to feel and expect the worst from the pain, from catastrophizing the pain. Finally, the Pain Vigilance and Awareness Questionnaire was used to assess hypervigilance or awareness of pain.

The researchers found the pain program resulted in an improvement in disability as patients felt better both mentally and physically over the 4-week program period and the 6 months following, although there was a small loss in treatment gains during the follow-up period. The authors pointed out, “If patients are less distressed by their pain, their pain is less likely to interfere with their ability to socialize and their general sense of well-being.”

Interestingly, the researchers also found that participating in the program didn’t affect all aspects of pain. For example, the timeline and control beliefs about pain were not changed, and even dropped in some cases. Nor was there a significant change in terms of how patients were aware or hypervigilant of the pain.

The authors admit there were some limitations to their study, including the small sample size and the inability to determine cause and effect. However, the authors do feel that this study do note an improvement in physical functioning of 26 percent, and in mental functioning by 23 percent.

Complex regional pain syndrome (CRPS) was once thought to affect only adults, but over the past 30 years, doctors have been diagnosing CRPS more often in patients under 18 years of age. Originally called reflex sympathetic dystrophy, or RSD, the descriptions of the syndrome were defined and the name changed to reflect two types of the syndrome: CRPS type 1 and CRPS type 2.

Despite the change in name and description, doctors still don’t know what the pathophysiology or causes are. They do know that the quality and type of pain varies from person to person, and can change in one person over time. The authors of this study looked at pain reports and patterns in children and adolescents with CRPS using not only standard neurological or nerve testing, but also – for the first time with children – quantitative sensory testing, or QST, was used. QST is a computer testing system that assesses damage to the nerve endings, testing their reactions to vibrations and changes in temperature. These findings are then compared with the same tests performed on the patient’s non-affected side.

The researchers recruited 63 patients between the ages of 7 and 17 years who had been diagnosed with CRPS. After applying the inclusion criteria and performing preliminary tests, 42 patients (40 girls) remained in the final study group. The patients were, on average, 13.2 years old. All patients had developed CRPS following a specific injury: 13 from sports-related injury, 10 from an accidental sprain or strain, 3 fractures, 3 after surgery, 3 after a soft tissue injury, and 1 after experiencing a deep vein thrombosis, or a clot in a vein. The average length of time that pain has been present was 12.6 months, ranging from 0.5 to 72 months. Besides the pain, other reported symptoms were: color changes to the skin (red or purple) in 28 patients, excessive sweating in the area in 12, dry skin in 15, swelling in 25, a change in hair in the region (less or more) in 28, and a change in nail growth in 7. A warmer skin temperature at the affected area was reported in 20 patients and cooler temperature in 5.

When the patients were examined, 23 patients showed signs of mild-to-moderate muscle wasting and weakness in the affected area, 8 showed mild wasting, and 1 patient had a tremor. Thirty patients were unable or unwilling to bear weight on the affected foot or leg because of the pain.

The researchers reported that, in this study, the onset of CRPS in early teens and the suddenness of the onset were the most common factors, a fact that was in line with previous study findings. Findings are different from that of adults with CRPS because in children and teens, females are overwhelmingly in the majority of CRPS patients with a ratio of 5-13.1 to 1. As well, adults tend to have more tremors than the children.

The results of the QST showed that the intense reaction to cold was higher than to heat, but still low when compared with adults (33.3 percent versus 74-100 percent). Pain reaction to heat was 16.7 percent in children and between 14 percent and 55 percent in adults. Reaction to vibrations in the study group did not differ much from the control group.

The researchers point out that their study did have some limitation, among them the testing was done at the site where pain was most severe. However, the researchers say that their study shows QST can be used in most children with CRPS to find out what alterations in the nerves they are experiencing.

Chronic itch can be just as unpleasant and difficult to live with as is chronic pain and it has many similarities to chronic pain. There is ongoing research to determine the causes of chronic itching, what exactly it has in common with pain, and how best to treat it.

In one study of patients who were undergoing dialysis, researchers found that of the 18,000 patients, there was a 17 percent higher mortality risk among those who experienced a chronic itch, or pruritis. Another large study of 18,770 subjects found that more than 8 percent of them complained of chronic itching and that this chronic itching was also associated with poorer overall health.

In trying to understand the mechanism of chronic itch, researchers have found that although pain can go deep into the body, itching remains on the skin or in some areas like the mouth, throat, etc. What they also found was that while chronic pain can be caused by a sensitization of nerve endings, so may chronic itching. An interesting finding from recent studies showed that subjects who experience chronic itch react differently to repetitive painful stimuli than do subjects who do not have chronic itching. Those with the itching felt stimuli like electrical current, heat, and scratching pain as itching, while those without chronic pain found that such stimulation helped ease an itch. Therefore, those without chronic itch would ease their itching by scratching, while those with chronic itch would just aggravate the sensation, causing it to worsen.

When studying neuropathic itch, or itch that follows a nerve pathway, it was found that the neuropathic itch was similar to neuropathic pain. This meant the itching also involved a burning and/or stinging sensation, as well as a prickly type of feeling. This is seen in 40 percent of patients who have had shingles and developed post herpetic neuralgia, a burning pain that continues along the rash area of shingles after the shingles lesions have healed.

Chronic itching could also be caused by interruptions in the transmissions between the body and the brain. People who take opioids, controlled medications usually prescribed for pain, or other medications for pain, could experience a chronic itch as a side effect.

Unfortunately, by not clearly understanding what causes chronic itching, treatment may not be effective. Right now, there are no medications that are specifically for treating itching, but there are medications that can help some people with certain types of itching. For example, some people get relief from anti-depressants and/or anti-seizure medications. Others get some relief from topical (creams or ointments) medications, which could be local anesthetics or anti-inflammatories. Interestingly, aspirin in a topical form may provide relief, but not aspirin in a pill form. Some research is being done with a type of medication that can work against the itching caused by the opioid medications, called opioid-antagonists. This research is showing some promise for people with severe untreatable itching.

Anger management styles vary among people but generally fall into two groups. There’s the anger-in style: holding anger in without expressing it (hiding emotion). And there’s the anger-out style: verbally or physically showing anger.

In this study, researchers look to see if anger management style affects endogenous opioid levels in response to pain. Endogenous opioids refer to narcotic-like chemicals released naturally by the body in response to pain.

Two groups of subjects were included. One group included healthy adults without back pain. They were between the ages of 18 and 55. The second group was matched by age and gender but had chronic low back pain (LBP). LBP was defined as pain lasting at least three months. The pain was rated at least a three on a scale from zero (no pain) to 10 (worst pain).

Blood levels of beta-endorphin (BE) were measured before and after three trials of pain. Pain was delivered by pressure to the index finger, cutting off blood supply to the forearm, and applying heat to the underside of the forearm. Everyone also filled out several surveys on pain, anxiety, depression, and anger.

They analyzed the blood samples and correlated them with the results of the surveys. They found that:

Complex regional pain syndrome (CRPS) and dystonia often occur together after a traumatic event. Does one cause the other? Or is it a coincident that they develop around the same time? In this review article, Dr. Schott from the National Hospital for Neurology and Neurosurgery in London, England looks at the data so far to find an answer.

CRPS is a collection of signs and symptoms including pain, skin temperature changes, and other sensory changes usually affecting the arm and/or hand. Loss of motion and function are common. The condition occurs after a traumatic injury.

Dystonia is a movement disorder. Weakness, stiffness, and clumsiness are the main features for some patients. In other cases, tremors, jerks, or twisting of the body part occur.

Not all patients with CRPS develop dystonia but many do. And the timing can be anywhere from a week to five years before the dystonia starts to show up. There are a few cases where dystonia occurs first, and then CRPS develops, but it’s usually the other way around.

The symptoms of CRPS may even get better as the dystonia comes on. This suggests that separate mechanisms are at play. Scientists generally agree that both problems stem from a dysregulation of the central nervous system. But exactly what happens in each condition is still a mystery.

Doctors are looking for predisposing factors for the onset of dystonia. Does it only occur when there’s a bone fracture? Or is it more likely to develop when the limb has been in a cast? Does surgery trigger it? Perhaps there are genetic or environmental factors.

Right now there are more questions than answers. The complex interaction of the nervous system with the immune system and the motor system are part of the picture. What are the biologic and mechanical pathways? This remains unknown and is still the focus of many studies.

The world is becoming more of a single research community. As this happens, scientists are looking for ways to measure and report outcomes so they can be compared from study to study. The World Health Organization (WHO) is helping foster this kind of communication.

They have developed a three-part tool called the International Classification of Functioning Disability and Health (ICF). The ICF will help health care professionals study and discuss any health problem. This includes chronic pain. The ICF uses three main outcomes. These include: impairment, activity limitations, and participation restrictions.

In this study, researchers match a survey called the Chronic Pain Grade Questionnaire (CPG) against the ICF to see if items measured in the CPG match the three categories of the ICF.

They asked 12 health professionals (doctors and researchers) to read each of the seven items on the CPG survey. Then they identified which of the three ICF outcomes each item was measuring.

They found that all three ICF outcomes were measured by the CPG. Some items were easily classified as a single outcome measure. But some of the survey questions could be put in more than one of the three ICF outcomes.

Mixed items like this can lead to conflation. Conflation is the error of treating two distinct concepts or results as if they were one. This means that according to the ICF model, the CPG combines results to come to one conclusion.

The authors say the CPG can still be used but extra analysis may be needed. It will be important to measure the three ICF outcomes independently without overlap. In this way, scientists can separate out how often impairment, activity limitations, and participation restrictions occur with each painful condition.

This information will help public health organizations like the WHO to find ways to reduce disability. Future studies should be designed to measure each ICF item individually.

Scientists are working hard to understand how nerve pain works. The hope is to find a way to stop chronic nerve pain or even prevent it from occurring after a nerve injury.

In this animal study, rats were used to examine crushed nerve cells. The EphB/ephrinB system was the focus. This system is known to be part of the signaling mechanism for nerve pain.

Three groups of rats were included. One (experimental) group had a specific lumbar nerve root (L5) crushed. The second (sham) group had surgery to expose the nerve but nothing was done to it (no crush injury). The third (naive) group did not have any surgery done.

Nerve tissue was removed from all three groups and analyzed. The researchers were able to trace the levels of each protein and its receptor in the EphB/ephrinB system. They recorded the levels each day up to day 28 after surgery.

They found that ephrinB2 increased in the neurons (nerve cells) after nerve injury. It reached a maximum level on day seven and gradually decreased until day 28. Its receptor (EphB1) was increased in the spinal cord up to day 28.

In a second step of this experiment, a substance called small interference RNA (siRNA) was found to decrease pain levels. It does this by knocking out the ephrinB2.

The authors concluded that the ephrin system does play a role in nerve pain. It appears that there are specific receptors for ephrinB2 in the neurons of the spinal cord. These receptors are waiting for ephrinB2 to come along. If this signaling pathway can be interrupted, then scientists might be able to develop a drug using siRNA to block nerve pain.

Complex regional pain syndrome, or CRPS, can develop after an injury, but the cause isn’t yet understood. Researchers do know that inflammation plays a role and previous studies have suggested that the body’s reaction in CRPS can be similar to that of a burn. Researchers looking into burn treatment have found that giving high doses of vitamin C to burn patients helped reduced the amount of fluid they needed and reduced the swelling. With this in mind, the authors of this study wanted to see if giving vitamin C to patients with a new broken wrist would decrease their chances of developing CRPS.

The study took place at 3 hospitals in the Netherlands and involved 416 women who had a total of 427 wrist fractures. The patients were randomly chosen to receive vitamin C (317 women, 328 fractures) or placebo, a sugar pill, (99 women, 99 fractures). Among the women taking vitamin C, 96 took 200 mg, 114 took 500 mg and 118 took 1500 mg, per day. The patients did not know if they were taking the vitamin or the placebo. They were evaluated 1 week after the injury, when the cast was removed (at 4 or 5 weeks), again at 6 or 7 week, 12 weeks, and 26 weeks. They were evaluated one more time at 1 year by phone or by mail.

The researchers made a diagnosis of CRPS if the patient showed 4 of the following 5 symptoms at the affected wrist: unexplained pain out of proportion to the injury, skin color difference between the affected hand and the other hand, skin temperature difference between the affected hand and the other hand, swelling, and limited range of motion unrelated to the fracture.

The researchers found that 2.4 percent of the women in the vitamin C group developed CRPS while 10.1 percent in the placebo group did. When the researchers looked at the amount of vitamin C taken by the women, there wasn’t much of a difference between the women who took the lowest dose vitamin C (200 mg) and the women who took the placebo. But, there was a significant difference between the women who took the higher doses of the vitamin.

The average time for development of CRPS was 76 days (ranging from 30 to 166 days). One patient who had fractured both wrists developed CRPS in one, but not the other. She was taking 1500 mg of vitamin C. The researchers also found that when patients complained of discomfort from their casts, this could predict the development of CRPS. This was similar to findings from previous studies, according to the authors.

The authors point out some limitations in the study, including the number of patients and verification of patient compliance. Nonetheless, they conclude that administration of 500 mg of vitamin C following a wrist fracture, for 50 days, may prevent CRPS.