Prevalence of chronic pain after traumatic brain injury: a systematic review

CONTEXT

The Centers for Disease Control and Prevention estimates that approximately 1.4 million US individuals sustain traumatic brain injuries (TBIs) per year. Previous reports suggest an association between TBI and chronic pain syndromes (eg, headache) thought to be more common in patients with mild TBI and in those who have sustained brain injury from violent rather than unintentional trauma. Comorbid psychiatric disorders such as posttraumatic stress disorder (PTSD) may also mediate chronic pain symptoms.

OBJECTIVES

To determine the prevalence of chronic pain as an underdiagnosed consequence of TBI and to review the interaction between chronic pain and severity of TBI as well as the characteristics of pain after TBI among civilians and combatants.

EVIDENCE ACQUISITION

The Ovid/MEDLINE database was searched for articles published between 1951 and February 2008 using any combination of the terms brain injury, pain, headache, blast injury, and combat (combat disorders, war, military medicine, wounds and injuries, military personnel, veterans). The PubMed and MD Consult databases were searched in a similar fashion. The Cochrane Collaboration, National Institutes of Health Clinical Trials Database, Meta-Register of Current Controlled Trials, and CRISP databases were searched using the keyword brain injury. All articles in peer-reviewed journals reporting original data on pain syndromes in adult patients with TBI with regard to pain prevalence, pain category, risk factors, pathogenesis, and clinical course were selected, and manual searches were performed of their reference lists. The data were pooled and prevalence rates calculated.

EVIDENCE SYNTHESIS

Twenty-three studies (15 cross-sectional, 5 prospective, and 3 retrospective) including 4206 patients were identified. Twelve studies assessed headache pain in 1670 patients. Of these, 966 complained of chronic headache, yielding a prevalence of 57.8% (95% confidence interval [CI], 55.5%-60.2%). Among civilians, the prevalence of chronic pain was greater in patients with mild TBI (75.3% [95% CI, 72.7%-77.9%]) compared with moderate or severe TBI (32.1% [95% CI, 29.3%-34.9%]). Twenty studies including 3289 civilian patients with TBI yielded a chronic pain prevalence of 51.5% (95% CI, 49.8%-53.2%). Three studies assessed TBI among 917 veterans and yielded a pain prevalence of 43.1% (95% CI, 39.9%-46.3%). PTSD may mediate chronic pain, but brain injury appears to have an independent correlation with chronic pain.

CONCLUSIONS

Chronic pain is a common complication of TBI. It is independent of psychologic disorders such as PTSD and depression and is common even among patients with apparently minor injuries to the brain.

Cortical reorganization during recovery from complex regional pain syndrome

OBJECTIVE

To characterize reorganization of the primary somatosensory cortex (S1) during healing process in complex regional pain syndrome (CRPS).

BACKGROUND

Recently, the authors showed extensive reorganization of the S1 cortex contralateral to the CRPS affected side. Predictors for these plastic changes were CRPS pain and the extent of mechanical hyperalgesia. It is unclear how these S1 changes develop following successful therapy.

METHODS

The authors used magnetic source imaging to explore changes in the cortical representation of digits (D) 1 and 5 in relation to the lower lip on the unaffected and affected CRPS side in 10 patients during a year or more of follow-up.

RESULTS

Cortical reorganization reversed coincident with clinical improvement. A reduction of CRPS pain correlated with recovery from cortical reorganization.

CONCLUSIONS

Changes of the somatotopic map within the S1 cortex may depend on CRPS pain and its recovery.

Complex regional pain syndrome

Complex regional pain syndrome is a chronic pain condition characterized by autonomic and inflammatory features. It occurs acutely in about 7% of patients who have limb fractures, limb surgery, or other injuries. Many cases resolve within the first year, with a smaller subset progressing to the chronic form. This transition is often paralleled by a change from "warm complex regional pain syndrome," with inflammatory characteristics dominant, to "cold complex regional pain syndrome" in which autonomic features dominate. Multiple peripheral and central mechanisms seem to be involved, the relative contributions of which may differ between individuals and over time. Possible contributors include peripheral and central sensitization, autonomic changes and sympatho-afferent coupling, inflammatory and immune alterations, brain changes, and genetic and psychological factors. The syndrome is diagnosed purely on the basis of clinical signs and symptoms. Effective management of the chronic form of the syndrome is often challenging. Few high quality randomized controlled trials are available to support the efficacy of the most commonly used interventions. Reviews of available randomized trials suggest that physical and occupational therapy (including graded motor imagery and mirror therapy), bisphosphonates, calcitonin, subanesthetic intravenous ketamine, free radical scavengers, oral corticosteroids, and spinal cord stimulation may be effective treatments. Multidisciplinary clinical care, which centers around functionally focused therapies is recommended. Other interventions are used to facilitate engagement in functional therapies and to improve quality of life.

Complex regional pain syndrome: are the IASP diagnostic criteria valid and sufficiently comprehensive?

This is a multisite study examining the internal validity and comprehensiveness of the International Association for the Study of Pain (IASP) diagnostic criteria for Complex Regional Pain Syndrome (CRPS). A standardized sign/symptom checklist was used in patient evaluations to obtain data on CRPS-related signs and symptoms in a series of 123 patients meeting IASP criteria for CRPS. Principal components factor analysis (PCA) was used to detect statistical groupings of signs/symptoms (factors). CRPS signs and symptoms grouped together statistically in a manner somewhat different than in current IASP/CRPS criteria. As in current criteria, a separate pain/sensation criterion was supported. However, unlike in current criteria, PCA indicated that vasomotor symptoms form a factor distinct from a sudomotor/edema factor. Changes in range of motion, motor dysfunction, and trophic changes, which are not included in the IASP criteria, formed a distinct fourth factor. Scores on the pain/sensation factor correlated positively with pain duration (P<0. 001), but there was a negative correlation between the sudomotor/edema factor scores and pain duration (P<0.05). The motor/trophic factor predicted positive responses to sympathetic block (P<0.05). These results suggest that the internal validity of the IASP/CRPS criteria could be improved by separating vasomotor signs/symptoms (e.g. temperature and skin color asymmetry) from those reflecting sudomotor dysfunction (e.g. sweating changes) and edema. Results also indicate motor and trophic changes may be an important and distinct component of CRPS which is not currently incorporated in the IASP criteria. An experimental revision of CRPS diagnostic criteria for research purposes is proposed. Implications for diagnostic sensitivity and specificity are discussed.

Relation between sympathetic vasoconstrictor activity and pain and hyperalgesia in complex regional pain syndromes: a case-control study

BACKGROUND

Complex regional pain syndromes can be relieved by sympathetic blockage. The mechanisms of sympathetically maintained pain (SMP) are unclear. We aimed to establish the effect of physiological sympathetic cutaneous vasoconstrictor activity on pain and hyperalgesia in patients with complex regional pain syndromes.

METHODS

High and low cutaneous vasoconstrictor activity was produced by whole-body cooling and warming (thermal suit) in 13 patients with type I disease and in ten controls. The degree of cutaneous vasoconstrictor discharge was monitored by measurement of skin blood flow and temperature at the arm and leg. Local skin temperature at the affected region was fixed at 35 degrees C. Pain was quantified during high and low cutaneous vasoconstrictor activity (intensity of spontaneous pain, area of mechanical hyperalgesias, heat-pain thresholds). Furthermore, pain was measured before and after diagnostic sympathetic blockage to identify patients with SMP and sympathetically independent pain.

FINDINGS

In patients with SMP, intensity of spontaneous pain significantly increased, by 22%, and spatial distribution of mechanical dynamic and punctate hyperalgesia increased by 42% and 27%, respectively, during high sympathetic activity compared with low activity. Heat-pain thresholds did not differ during high and low cutaneous vasoconstrictor activity (cold and warm state, 43.6 degrees C vs 44.6 degrees C). Pain relief after sympathetic blockage correlated with augmentation of spontaneous pain after experimental stimulation of cutaneous vasoconstrictor activity (r=0.6, p=0.0244).

INTERPRETATION

We have shown that in complex regional pain syndromes with SMP, physiological activation of cutaneous vasoconstrictor neurons projecting to the painful arm or leg enhances spontaneous pain and hyperalgesia. We postulate that there is a pathological interaction between sympathetic and afferent neurons within the skin.

Concentration-effect relationship of intravenous lidocaine on the allodynia of complex regional pain syndrome types I and II

BACKGROUND

Several lines of evidence suggest that neuropathic pain (including Complex Regional Pain Syndrome [CRPS] I and CRPS II) is mediated in part by an increase in the density of voltage-sensitive sodium channels in injured axons and the dorsal root ganglion of injured axons. This study sought to characterize the effects of intravenous lidocaine (a sodium channel blocker) on acute sensory thresholds within the painful area and the size of the painful area in patients suffering from CRPS I and II.

METHODS

This study used a randomized, double-blind, placebo-controlled design in 16 subjects suffering from CRPS I and II with a prominent allodynia. Each subject received an intravenous infusion of lidocaine and diphenhydramine separated by 1 week. A computer-controlled infusion pump targeted stair-step increases in plasma levels of lidocaine of 1, 2, and 3 microg/ml. At baseline and at each plasma level, spontaneous and evoked pain scores and neurosensory testing within the painful area were measured. The neurosensory testing consisted of thermal thresholds, tactile thresholds and the area of allodynia to punctate, and stroking and thermal stimuli.

RESULTS

Intravenous lidocaine and diphenhydramine had no significant effect on the cool, warm, or cold pain thresholds. However, lidocaine caused a significant elevation of the hot pain thresholds in the painful area. Intravenous lidocaine caused a significantly decreased response to stroking and cool stimuli in the allodynic area. There was also a significant decrease in pain scores to cool stimuli at all plasma levels and the spontaneous pain at the highest plasma level.

CONCLUSIONS

This study demonstrates that intravenous lidocaine affects pain in response to cool stimuli more than mechanical pain in subjects with neuropathic pain. There is a lesser effect on spontaneous pain and pain induced by stroking stimuli and no effect on the pain induced by punctate stimuli.

Laminectomy versus percutaneous electrode placement for spinal cord stimulation

OBJECTIVE

The purpose of this study was to compare the long-term effectiveness of spinal cord stimulation using laminectomy-style electrodes versus that using percutaneously implanted electrodes.

METHODS

Forty-one patients underwent an initial trial period of spinal cord stimulation with temporary electrodes at Duke Medical Center between December 1992 and January 1998. A permanent system was implanted if trial stimulation reduced the patient's pain by more than 50%. Median long-term follow-up after permanent electrode placement was 34 months (range, 6-66 mo). Severity of pain was determined postoperatively by a disinterested third party using a visual analog scale and a modified outcome scale.

RESULTS

Twenty-seven (66%) of the 41 patients participating in the trial had permanent electrodes placed. Visual analog scores decreased an average of 4.6 among patients in whom electrodes were placed via laminectomy in the thoracic region (two-tailed t test, P < 0.0001). Patients who underwent percutaneous placement of thoracic electrodes had an average decrease of 3.1 in their visual analog scores (two-tailed t test, P < 0.001). Electrodes placed through laminectomy furnished significantly greater long-term pain relief than did those placed percutaneously, as measured by a four-tier outcome grading scale (P = 0.02).

CONCLUSION

Spinal cord stimulation is an effective treatment for chronic pain in the lower back and lower extremities that is refractory to conservative therapy. Electrodes placed via laminectomy in the thoracic region appear to be associated with significantly better long-term effectiveness than are electrodes placed percutaneously.

Comparison of prednisolone with piroxicam in complex regional pain syndrome following stroke: a randomized controlled trial

BACKGROUND

Complex regional pain syndrome (CRPS) following stroke aggravates morbidity. CRPS is categorized as CRPSI when no clear nerve injury is defined, and CRPSII when associated with clear nerve injury.

AIM

To compare the effect of prednisolone with that of piroxicam in patients with CRPSI following stroke.

DESIGN

Randomized controlled trial.

METHODS

Patients with CRPSI fulfilling the inclusion criteria (n = 60) underwent a detailed neurological examination, cranial CT scan, radiograph of chest and shoulder joint, blood counts and serum chemistry. Severity of stroke was assessed by the Canadian Neurological Scale (CNS), CRPS by scoring sensory, autonomic and motor symptoms, and activity of daily living by Barthel index (BI) score. Patients were randomly assigned prednisolone 40 mg or piroxicam 20 mg daily, and outcome was assessed at 1 month on the basis of CRPS and BI score.

RESULTS

Mean patient age was 56 years and 20 were female. Baseline clinical and radiological parameters were comparable between the two groups. In the prednisolone group, 83.3% patients showed significant improvement, compared to 16.7% in the piroxicam group. The mean change in CRPS score in prednisolone group was 6.47 (95%CI 4.37-7.36), whereas in piroxicam group it was only 0.47. The mean change in BI score was 7.9 (95%CI 0.82-5.98) in the prednisolone group, and 4.5 in the piroxicam group.

DISCUSSION

In this patient group, prednisolone resulted in significant improvement in the symptoms and signs of CRPSI following stroke, compared to piroxicam. Both drugs produced an improvement in the BI score.

Signs and Symptoms in 1,043 Patients with Complex Regional Pain Syndrome

Complex regional pain syndrome (CRPS) is a complex pain disorder that can emerge after limb trauma or a lesion in the peripheral nervous system. Typical features include continuing pain, sensory, vasomotor, sudomotor, motor, and trophic changes as well as edema. These signs provide the basis of CRPS diagnosis. A detailed description of the signs, symptoms, and medical history of CRPS could potentially facilitate an earlier and more accurate diagnosis. The aim of this study was to provide such a description, on the basis of epidemiological measures, clinical presentation, and a thorough description of pain sensations. Some signs (eg, differences of skin temperature >1°C), which have been thought to be crucial for diagnosis, were less common than assumed. We identified 11 distinct etiological triggers, which cover more than 99% of the study participants. We developed a weighted score on the basis of the most decisive data, which achieved a sensitivity of .869 and a specificity of .829, compared with .819 and .679 for the Budapest criteria. The weighted diagnostic criteria may help to better aid in distinguishing CRPS from other pain disorders.

PERSPECTIVE

This article provides a retrospective epidemiological analysis of 1,043 CRPS patients compared with 421 patients with other pain disorders. The findings could potentially facilitate a more reliable and earlier diagnosis of CRPS, a better differentiation from other pain disorders, and ultimately in a more targeted and effective therapy.

Chronic neuropathic pain. Mechanisms, diagnosis, and treatment

BACKGROUND

The management of chronic pain represents a significant public health issue in the United States. It is both costly to our health care system and devastating to the patient's quality of life. The need to improve pain outcomes is reflected by the congressional declaration of the present decade as the "Decade of Pain Control and Research," and the acknowledgment in January 2001 of pain as the "fifth vital sign" by the Joint Commission of Healthcare Organizations.

REVIEW SUMMARY

At present, therapeutic options are largely limited to drugs approved for other conditions, including anticonvulsants, antidepressants, antiarrhythmics, and opioids. However, treatment based on the underlying disease state (eg, postherpetic neuralgia, diabetic neuropathy) may be less than optimal, in that 2 patients with the same neuropathic pain syndrome may have different symptomatology and thus respond differently to the same treatment. Increases in our understanding of the function of the neurologic system over the last few years have led to new insights into the mechanisms underlying pain symptoms, especially chronic and neuropathic pain.

CONCLUSIONS

The rapidly evolving symptom- and mechanism-based approach to the treatment of neuropathic pain holds promise for improving the quality of life of our patients with neuropathic pain.

Demystifying Poststroke Pain: From Etiology to Treatment

Pain after stroke is commonly reported but often incompletely managed, which prevents optimal recovery. This situation occurs in part because of the esoteric nature of poststroke pain and its limited presence in current discussions of stroke management. The major specific afflictions that affect patients with stroke who experience pain include central poststroke pain, complex regional pain syndrome, and pain associated with spasticity and shoulder subluxation. Each disorder carries its own intricacies that require specific approaches to treatment and understanding. This review aims to present and clarify the major pain syndromes that affect patients who have experienced a stroke in order to aid in their diagnosis and treatment.

Changes resembling complex regional pain syndrome following surgery and immobilization

The study of complex regional pain syndrome (CRPS) in humans is complicated by inhomogeneities in available study cohorts. We hoped to characterize early CRPS-like features in patients undergoing hand surgery. Forty-three patients were recruited from a hand surgery clinic that had elective surgeries followed by cast immobilization. On the day of cast removal, patients were assessed for vasomotor, sudomotor, and trophic changes, and edema and pain sensitization using quantitative sensory testing. Pain intensity was assessed at the time of cast removal and after 1 additional month, as was the nature of the pain using the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS). Skin biopsies were harvested for the analysis of expression of inflammatory mediators. We identified vascular and trophic changes in the surgical hands of most patients. Increased sensitivity to punctate, pressure, and cold stimuli were observed commonly as well. Moreover, levels of IL-6, TNF-alpha, and the mast cell marker tryptase were elevated in the skin of hands ipsilateral to surgery. Moderate-to-severe pain persisted in the surgical hands for up to 1 month after cast removal. Exploratory analyses suggested interrelationships between the physical, quantitative sensory testing, and gene expression changes and pain-related outcomes.

PERSPECTIVE

This study has identified CPRS-like features in the limbs of patients undergoing surgery followed by immobilization. Further studies using this population may be useful in refining our understanding of CRPS mechanisms and treatments for this condition.

Complex regional pain syndrome complicating total knee arthroplasty

PURPOSE

To compare the long-term outcome of patients diagnosed with complex regional pain syndrome-type 1 (CRPS-1) after total knee arthroplasty (TKA) with those of uncomplicated TKA knees and preoperative osteoarthritic knees.

METHODS

Medical records of 1280 patients who underwent TKA for osteoarthritis were retrospectively reviewed; 8 were diagnosed as having symptoms and signs consistent with CRPS after TKA. Patients with primary inflammatory arthritis, signs of component loosening, malpositioning, or of infected arthroplasty were excluded. No patient had signs of CRPS prior to operative intervention. The 8 patients were compared with 2 groups of age- and sex-matched controls: uncomplicated TKA knees and preoperative osteoarthritic knees. Patients were followed up for a mean of 54 (range, 13-111) months and their range of movement, Western Ontario and McMaster Universities Osteoarthritis Index, SF-36 questionnaire scores, and Knee Society scores were assessed and compared.

RESULTS

After appropriate treatment, most CRPS complicated patients had similar scores on SF-36, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society scores when compared with uncomplicated TKA patients. Scores for CRPS complicated patients were significantly improved when compared with preoperative osteoarthritic patients. The incidence of CRPS after TKA was 0.7%.

CONCLUSION

When managed early, patients complicated with CRPS after TKA have a similar prognosis to patients with uncomplicated TKA.

Evidence for a mismatch between the brain’s movement control system and sensory system as an explanation for some pain-related disorders

The motor-control system usually operates below our conscious level, and we only become aware of the complex interaction between desired movements and actual movements when an irregularity in the system occurs. Recently, it has been proposed that such discordances in sensorimotor function may generate pain and other somaesthetic disturbances. This article describes this model of pain and determines how it may be applied to a range of chronic pain conditions in which there is a lack of obvious causal pathology, including complex regional pain syndrome. In addition, we discuss the clinical implications of such a theory and examine how enhancing sensory feedback may reduce chronic pain.

Complete recovery from intractable complex regional pain syndrome, CRPS-type I, following anesthetic ketamine and midazolam

OBJECTIVE

To describe the treatment of an intractable complex regional pain syndrome I (CRPS-I) patient with anesthetic doses of ketamine supplemented with midazolam.

METHODS

A patient presented with a rapidly progressing contiguous spread of CRPS from a severe ligamentous wrist injury. Standard pharmacological and interventional therapy successively failed to halt the spread of CRPS from the wrist to the entire right arm. Her pain was unmanageable with all standard therapy. As a last treatment option, the patient was transferred to the intensive care unit and treated on a compassionate care basis with anesthetic doses of ketamine in gradually increasing (3-5 mg/kg/h) doses in conjunction with midazolam over a period of 5 days.

RESULTS

On the second day of the ketamine and midazolam infusion, edema, and discoloration began to resolve and increased spontaneous movement was noted. On day 6, symptoms completely resolved and infusions were tapered. The patient emerged from anesthesia completely free of pain and associated CRPS signs and symptoms. The patient has maintained this complete remission from CRPS for 8 years now.

CONCLUSIONS

In a patient with severe spreading and refractory CRPS, a complete and long-term remission from CRPS has been obtained utilizing ketamine and midazolam in anesthetic doses. This intensive care procedure has very serious risks but no severe complications occurred. The psychiatric side effects of ketamine were successfully managed with the concomitant use of midazolam and resolved within 1 month of treatment. This case report illustrates the effectiveness and safety of high-dose ketamine in a patient with generalized, refractory CRPS.

Neonatal Chronic Hind Paw Inflammation Alters Sensitization to Intradermal Capsaicin in Adult Rats: A Behavioral and Immunocytochemical Study

The present studies were conducted to examine functional consequences of postnatal chronic inflammation, initiated during a critical developmental period, on capsaicin-evoked hyperalgesia and neuronal activation in adulthood. Rats received a unilateral intraplantar injection of complete Freund's adjuvant (CFA; diluted 2:1 in saline) on postnatal day 0 (P0-CFA) or 14 (P14-CFA). Separate groups received an equivalent volume of saline on P0 (P0-vehicle) or were untreated (P0-untreated). Increases in capsaicin-evoked thermal and mechanical hyperalgesia and allodynia were observed in adult P0-CFA-treated rats relative to control conditions. By contrast, this enhancement was absent in P14-CFA-treated rats, suggesting that the developmental period differentially affects the appearance of the observed behavioral phenotype. Capsaicin-evoked nocifensive behavior was also lower in P14-CFA-treated rats relative to P0-CFA-treated rats. Capsaicin-evoked Fos protein expression was increased in the superficial and neck regions of the dorsal horn of adult P0-CFA-treated rats relative to P0-vehicle-treated rats. These changes were absent in the nucleus proprius and ventral horn. The present data are consistent with the hypothesis that neonatal chronic inflammation permanently alters sensitivity to pain in adulthood, consistent with modulation of primary afferent activation and central sensitization in response to a subsequent nociceptive challenge in adulthood.

PERSPECTIVE

Chronic inflammation during development can induce profound alterations in sensory processing later in life. Here we show that long-term inflammation initiated at critical developmental stages sensitizes both behavioral and neuronal responses to nociceptor stimulation in adulthood. An ongoing sensitization of the spinal cord is induced by the postnatal inflammatory insult.

Musculoskeletal manifestations of diabetes mellitus

The prevalence of Type 1 and Type 2 diabetes are increasing significantly worldwide. Whilst vascular complications of diabetes are well recognized, and account for principle mortality and morbidity from the condition, musculoskeletal manifestations of diabetes are common and whilst not life threatening, are an important cause of morbidity, pain and disability. Joints affected by diabetes include peripheral joints and the axial skeleton. Charcot neuroarthropathy is an important cause of deformity and amputation associated with peripheral neuropathy. A number of fibrosing conditions of the hands and shoulder are recognized, including carpal tunnel syndrome, adhesive capsulitis, tenosynovitis and limited joint mobility. People with diabetes are more prone to gout and osteoporosis. Management of these conditions requires early recognition and close liaison between diabetes and rheumatology specialists.

Clinical expression profiles of complex regional pain syndrome, fibromyalgia and a-specific repetitive strain injury: More common denominators than pain?

PURPOSE

To systematically evaluate and compare the clinical manifestations, disease course, risk factors and demographic characteristics of Complex Regional Pain Syndrome type 1 (CRPS), fibromyalgia (FM) and a-specific Repetitive Strain Injury (RSI).

METHOD

A literature search was performed using terms related to the aforementioned topics and diseases. Only original clinical studies that included at least 20 subjects were eligible.

RESULTS

Fifty-nine studies on CRPS, 73 on FM and 7 on a-specific RSI were identified. The diseases show similarities in age distribution, male-female ratio, pain characteristics and sensory signs and symptoms. Motor, autonomic and trophic changes are frequently reported in CRPS, but only occasionally in FM and RSI. Systemic symptoms are found in patients with CRPS and FM, and in a subgroup of patients with RSI. In all three disorders, symptoms usually start locally, but may spread to other body regions later, which, in the case of FM, is a prerequisite for diagnosis. Disease onset is always, usually, or occasionally of traumatic origin in RSI, CRPS and FM, respectively. Anxiety and depression are more frequent in patients compared to controls, but probably not very different from patients with other pain conditions or chronic diseases.

CONCLUSIONS

Apart from some obvious differences between CRPS, FM and RSI, the similarities are conspicuous. The common features of CRPS, FM and a-specific RSI may suggest that a common pathway is involved, but until patients with these type of symptoms are assessed with a uniform assessment procedure, a thorough comparison cannot be made. A systematic evaluation of patients with a suspected diagnosis of CRPS, FM or RSI, may lead to a better appreciation of the differences and similarities in these diseases and help to unravel the underlying mechanisms.

The Incidence of Complex Regional Pain Syndrome After Fasciectomy for Dupuytren’s Contracture: A Prospective Observational Study of Four Anesthetic Techniques: Retracted

The development of complex regional pain syndrome (CRPS) is not an uncommon complication after Dupuytren's surgery. Despite increasing research interest, little is known regarding which patients are at increased risk for developing CRPS and what is the optimal perioperative treatment strategy for preventing the occurrence of this disease after surgery. We prospectively evaluated the use of four anesthetic techniques (general anesthesia, axillary block, and IV regional anesthesia [IVRA] with lidocaine with or without clonidine) for patients undergoing fasciectomy for Dupuytren's contracture. All patients were followed in the Pain Management Center at 1, 3, and 12 mo postoperatively by a blinded physician to evaluate the presence of CRPS. Significantly (P < 0.01) more patients developed postoperative CRPS in the general anesthesia group (n = 25; 24%) and the IVRA lidocaine group (n = 12; 25%) compared with either the axillary block group (n = 5; 5%) or the IVRA lidocaine and clonidine group (n = 3; 6%). We conclude that axillary block or IVRA with clonidine offers a significant advantage for decreasing the incidence of CRPS compared with either IVRA with lidocaine alone or general anesthesia for patients undergoing Dupuytren's surgery.

Pain in central and peripheral demyelinating disorders

Moderate to severe pain is a common feature of central and peripheral demyelinating disorders. Pain in multiple sclerosis tends to occur when the disease is well-established and usually lingers infinitely. Pain in Guillain-Barré syndrome tends to be particularly severe at the time of initial presentation and usually resolves over 8 to 12 weeks. Pain in both conditions is generally caused by either the direct effects of nerve injury or the result of paralysis and prolonged immobilization. Pain syndromes are well-defined in each disorder based on the underlying pathophysiology. Treatment involves a variety of pharmacologic and nonpharmacologic approaches individualized for each specific pain syndrome.

Complex regional pain syndrome as a stress response

A man in his 50's with a prior traumatic brain injury and multiple psychiatric disorders developed acute pain and swelling in his left leg distal to the mid shin. These symptoms arose during an exacerbation of his post-traumatic stress disorder (PTSD). Among his traumatic memories, he reported having witnessed the combat injury and death of a friend who had lost his left leg distal to the mid shin. A diagnosis of conversion disorder was technically excluded because the findings met criteria for Complex Regional Pain Syndrome (CRPS) type I. Based on recent research into the neurobiology of CRPS, PTSD and conversion disorder, we propose a supraspinal mechanism which could explain how emotional stress can produce both symptoms and signs.

Patients with Ehlers Danlos syndrome and CRPS: a possible association?

Rare patients are left with chronic pain, vasodysregulation, and other symptoms that define complex regional pain syndrome (CRPS), after limb traumas. The predisposing factors are unknown. Genetic factors undoubtedly contribute, but have not yet been identified. We report four CRPS patients also diagnosed with the classical or hypermobility forms of Ehlers Danlos syndrome (EDS), inherited disorders of connective tissue. These patients had been diagnosed using standard diagnostic criteria for CRPS and for EDS. All had sustained joint injury; in three this had been surgically treated. The association of these two diagnoses leads us to hypothesize that EDS might contribute to the development of CRPS in one or more of the following ways: via stretch injury to nerves traversing hypermobile joints, increased fragility of nerve connective tissue, or nerve trauma from more frequent surgery. We review the clinical presentation of the different Ehlers Danlos syndromes and provide clinical criteria that can be used to screen CRPS patients for EDS for clinical or research purposes.