Does failed natural opioid modulation in regional sympathetic ganglia cause reflex sympathetic dystrophy?

Effect and mechanisms of exercise for complex regional pain syndrome

Complex regional pain syndrome characterized by severe pain and dysfunction seriously affects patients' quality of life. Exercise therapy is gaining attention because it can effectively relieve pain and improve physical function. Based on the previous studies, this article summarized the effectiveness and underlying mechanisms of exercise interventions for complex regional pain syndrome, and described the gradual multistage exercise program. Exercises suitable for patients with complex regional pain syndrome mainly include graded motor imagery, mirror therapy, progressive stress loading training, and progressive aerobic training. In general, exercise training for patients with complex regional pain syndrome not only alleviates pain but also improves physical function and positive mental status. The underlying mechanisms of exercise interventions for complex regional pain syndrome include the remodeling of abnormal central and peripheral nervous system, the regulation of vasodilation and adrenaline levels, the release of endogenous opioids, and the increased anti-inflammatory cytokines. This article provided a clear explanation and summary of the research on exercise for complex regional pain syndrome. In the future, more high-quality studies with sufficient sample sizes may provide more exercise regimens and better evidence of efficacy.

Buprenorphine injection to the stellate ganglion in the treatment of upper body chronic pain syndromes

BACKGROUND

The injection of low dose buprenorphine to the sympathetic ganglia, termed "GLOA", Ganglionide Local Opioid Analgesia, is used to treat chronic pain in several European centres. It is not known whether the clinically observed GLOA effect in chronic pain syndromes is due to a specific effect of buprenorphine at the ganglia. We assessed whether GLOA, plus intramuscular saline, was more efficacious than the reverse, saline injection to the stellate plus intramuscular buprenorphine, termed SSB.

METHODS

We devised a randomized, double-blinded, controlled crossover trial to treat patients with chronic upper body pain syndromes. Patients first received either GLOA or SSB. Pain was assessed using pain diaries both before injection and over the first 8h and 6days afterwards, and was expressed as relative pain intensity post versus pre-injection pain.

RESULTS

The median relative pain intensity after injections did not differ between GLOA and SSB. Four patients reported a low, <50%, relative pain level over the first 8h after SSB only. Four patients did not complete the trial and were excluded. One patient with cardiomyopathy became acutely diaphoretic and fatigued after GLOA, his vital signs however remained stable.

CONCLUSIONS

We failed to show a superiority of GLOA over SSB. Our results suggest it unlikely that the clinically observed effect after a single GLOA injection is due to a specific action of buprenorphine at the stellate ganglion. The efficacy of GLOA is hereby questioned. The use of GLOA in patients with cardiomyopathy should be cautioned.

TRIAL REGISTRATION

ISRCTN59287260; http://www.controlled-trials.com/

Algodystrophy

Algodystrophy is a clinical syndrome characterized by intense locoregional pain, vasomotor and trophic changes and delayed recovery, mostly occurring after trauma or surgery. The variety of nomenclature reflects the spectrum of clinical presentations and the uncertain pathophysiology. Although most patients recover, it can result in persistent disability in some patients. The diagnosis is based mostly on clinical signs. The specificity and sensitivity of additional technical investigations, such as radionuclide scintigraphy and X-ray, is variable. Algodystrophy progresses in several stages, from an inflammation-like clinical picture to recovery or sequels. The management is mainly supportive and can be difficult in some patients, especially in persistent chronic cases or when recognized at a late stage. Management is based on the results of limited prospective controlled studies. There is a need for a better understanding of the pathophysiology and for prospective clinical studies about the natural course and the effect of treatment.

Complex regional pain syndrome and chiropractic

OBJECTIVE

Complex regional pain syndromes (CRPS) represent curious and difficult syndromes for both patient and clinician. CRPS presents as a triad of signs and symptoms, usually after a seemingly trivial injury to a peripheral joint or appendage. The clinical triad includes severe pain, vasomotor changes in and around the affected area, and trophic changes in the affected limb. Many of the acute symptoms are similar to those seen after many acute injuries, which makes an early diagnosis often times difficult. Current treatment protocols revolve around aggressive physical therapy plus pharmacologic interventions aimed at limiting sympathetic nervous system activity.

OBJECTIVE

To review the literature on CRPS regarding symptoms, diagnosis, treatment, and causal mechanisms and to discuss alternative treatment approaches and the possible role of chiropractic care in patient rehabilitation.

DATA SOURCES

Texts, review articles, and randomized clinical trials investigating treatments, causes, and epidemiology.

CONCLUSIONS

Recent research calls into question the predominant theories that view excessive sympathetic nervous system activity as the cause of CRPS. No evidence of an increase in sympathetic nervous system activity has been found, and new theories suggest that an increase in the sensitivity of neurotransmitter receptors may be the cause of CRPS. Alternatively, other research has suggested that a local inflammatory process may in fact cause CRPS. Although no research has been completed examining the role of chiropractic care in the treatment of CRPS, there is reason to believe that spinal manipulation may be beneficial to patients with CRPS.

Reflex sympathetic dystrophy. Timely diagnosis and treatment can prevent severe contractures

Reflex sympathetic dystrophy is a clinical syndrome consisting of persistent burning pain and varying degrees of vasomotor and trophic changes in an extremity after trauma. Although several mechanisms have been proposed, none have been universally accepted. Historically, treatment has involved sympathetic blockade or sympathectomy to prevent the proposed sympathetic hyperactivity. However, only a limited number of controlled studies have been conducted, and results have been controversial. The cornerstone of treatment is physical therapy to prevent the severe contractures that can result.

Reflex sympathetic dystrophy

Reflex sympathetic dystrophy presents with pain out of proportion to the cause, loss of function, and significant evidence of an autonomic disorder. These findings are often accompanied by psychological disturbances, which can dominate the condition. There are differences in the symptoms and signs during childhood. It is more frequent among girls than boys, and the legs are more often affected than the arms; and trophic changes may be absent. There may be no history of trauma, and the response to treatment is often satisfactory. There are a number of theories on etiology. A disorder of the sympathetic nervous system with increased activity has been suggested, but on the evidence available super-sensitivity to neurotransmitters is more likely. Also there may be a spinal, as well as a peripheral, component to the sensitivity. Other suggestions include the release of a pain substance, a disturbance of natural opioid metabolism, and an exaggerated inflammatory response. The diagnosis is mainly clinical, supported by X-ray examination, bone scans with Technetium 99m labelled diphosphonates, and a characteristic scintograph pattern. Laser Doppler flowmetry can also, be useful. The most effective preventative measure is control of pain and early mobilisation. Many treatments have been tried, but the response is variable. Drugs include analgesics, non-steroid anti-inflammatory drugs, anti-depressants, and steroids. Betablockers, with gradually increasing doses may help; as may vasodilators. Calcitonin, by intramuscular injection has been given a particularly favourable report. Physiotherapy is of prime importance. Some treatments are only likely to be considered in older children. Blocking of sympathetic pathways can be tried with paravertebral or epidural injections of local anesthetics. Regional intravenous injections of alpha adrenergic blocking agents distal to a tourniquet can relieve pain, but usually only transiently; and ketanserin may act favourably as a serotonin antagonist. Surgical sympathectomy can also be considered.

Reflex sympathetic dystrophy of the hand: an excessive inflammatory response?

In 23 patients with reflex sympathetic dystrophy (RSD) of the hand, scintigraphy with indium-111 labeled human non-specific polyclonal immunoglobulin G (In-111-IgG) was performed to investigate whether inflammatory characteristics are present in RSD. Both blood flow and accumulation over 48 h were assessed. Nineteen patients had increased flow to the affected hand, and 3 had decreased flow. One patient had bilateral RSD. Exercise provoked aggravation of complaints and signs in all patients. The affected/non-affected hand ratio (target-to-background, T/B) immediately before and after exercise did not change significantly. The T/B ratios 48 h after In-111-IgG injection were significantly higher in patients with RSD less than 5 months than in patients with RSD existing 5 months or longer. The T/B ratios 24 and 48 h after In-111-IgG injection were not correlated with the flow T/B ratios. In fact, 2 of the 3 patients with a decreased flow showed excess accumulation on the late images. Significantly more patients with early RSD, existing less than 5 months, had a positive In-111-IgG scintigraphy (14 of 17) than the patients with late RSD (1 of 6). Increased vascular permeability for macromolecules, an important characteristic of inflammation, appears to play a role in the development of RSD. This phenomenon is not flow-dependent.

Causalgia--reflex sympathetic dystrophy--sympathetically maintained pain: myth and reality

Causalgia, reflex sympathetic dystrophy, and sympathetically maintained pain (SMP) are a complex group of disorders, with symptoms of spontaneous/stimulus-induced pain and vasomotor, sudomotor or skeletomotor dysfunction of the involved area. Sympatholysis has been recommended for diagnosis/classification and treatment of these patients. Lack of adequate placebo control makes the physiologic response to this intervention unclear. Sensitization of wide dynamic range (WDR) neurons in the central nociceptive pathway has been proposed as a key element in pathophysiologic mechanisms of these disorders. Low threshold mechanoreceptors and nociceptors have been implicated as the primary afferents transmitting signals to or maintaining sensitization of WDR neurons in SMP. Vasomotor disturbances may result from antidromic vasodilatation, vasoparalytic dilatation, normal somatosympathetic reflexes, and denervation supersensitivity. There is conflicting information regarding the use of phentolamine and clonidine in these pain syndromes. Treatment of these patients remains a challenge given the many potential underlying mechanisms.

Morphine injected around the stellate ganglion does not modulate the sympathetic nervous system nor does it provide pain relief

Six patients with a presumptive diagnosis of upper limb reflex sympathetic dystrophy and 1 patient with anaesthesia dolorosa had pain and sympathetic activity assessed before and after injection of bupivacaine and morphine around the stellate ganglion. Sympathetic modulation was assessed by measuring the effect of each injection on the inspiratory gasping response (IGR), a measure of central arousal, the sympathetic skin response (SSR), a measure of peripheral sudomotor activity and the plethsymographic wave (PW), a measure of peripheral vasomotor activity. There were 5 women and 2 men with a mean age of 49 years (range: 41-66 years). The duration of pain varied from 9 months to 7 years. Bupivacaine abolished the IGR and SSR and increased the amplitude of the PW in all patients without any demonstrable sensory or motor blockade in the treated limb, nor did it have any effect on the contralateral IGR or PW. Bupivacaine did provide short-term pain relief in 4 out of 7 patients. Morphine did not produce any demonstrable effect on the sympathetic nervous system nor did it provide pain relief for any patient. Thus these data do not support injection of morphine around the stellate ganglion as it neither modulated sympathetic activity nor provided pain relief.