Reflex sympathetic dystrophy syndrome and neuromediators

Adult Complex Regional Pain Syndrome Type I: A Narrative Review

Complex regional pain syndrome type I (CRPS I) is a multifactorial painful disorder with a complex pathogenesis. Both peripheral and central mechanisms are involved. Acute CRPS I is considered to be an exaggerated inflammatory disorder; however, over time, because of altered function of the sympathetic nervous system and maladaptive neuroplasticity, CRPS I evolves into a neurological disorder. This review thoroughly describes the pathophysiological aspects of CRPS I and summarizes the potential therapeutic options. The mechanisms and targets of the treatment are different in the early and late stages of the disease. This current review builds on a previous review by this author group by deepening the role of the peripheral classic and neuronal inflammatory component in the acute stage of this painful disorder.

LEVEL OF EVIDENCE

Not applicable.

Complex regional pain syndrome type I: a comprehensive review

BACKGROUND

Complex regional pain syndrome type I (CRPS I), formerly known as reflex sympathetic dystrophy (RSD), is a chronic painful disorder that usually develops after a minor injury to a limb. This topical review gives a synopsis of CRPS I and discusses the current concepts of our understanding of CRPS I in adults, the diagnosis, and treatment options based on the limited evidence found in medical literature. CRPS I is a multifactorial disorder. Possible pathophysiological mechanisms of CRPS I are classic and neurogenic inflammation, and maladaptive neuroplasticity. At the level of the central nervous system, it has been suggested that an increased input from peripheral nociceptors alters the central processing mechanisms.

METHODS

A literature search was conducted using, as electronic bibliographic database, Medline from 1980 until 2014.

RESULTS

An early diagnosis and multidisciplinary treatment are necessary to prevent permanent disability.

CONCLUSIONS

The pharmacological treatment of CRPS I is empirical and insufficiently effective. Further research is needed regarding the therapeutic modalities discussed in the guidelines. Physical therapy is widely recommended as a first-line treatment. The efficacy of local anesthetic sympathetic blockade as treatment for CRPS I is questionable.

SBOTE study: extracorporeal shock wave therapy versus electrical stimulation after botulinum toxin type a injection for post-stroke spasticity-a prospective randomized trial

Research is on-going to identify new methods of biostimulation to increase the effect of botulinum toxin type A (BTX-A) in the treatment of spasticity. The Spasticity treated by Botulinum Toxin and ESWT (SBOTE) study is a prospective, randomized controlled trial assessing the effectiveness of extracorporeal shock wave therapy (ESWT) given immediately after BTX-A injections compared with electrical stimulation (ES) given immediately after BTX-A therapy for the management of focal upper limb spasticity in stroke patients. ES was given for 30 min twice a day for 5 days starting at 5 Hz; ESWT was given once a day for 5 days. At study follow-up, patients treated with BTX-A injections and ESWT showed a statistically greater significance and continuous decrease of spasticity measure (modified Ashworth scale [MAS]: 1.37, 1.75 and 1.58 at 15, 30 and 90 days post-treatment, respectively), of spasms (spasm frequency scale [SFS]: 0.8 and 0.25 at 30 and 90 days post-treatment, respectively) and of pain (visual analogue scale [VAS]: 1.94 and 1.87 at 30 and 90 days, respectively) compared with patients treated with BTX-A injections and ES (MAS: 2.37, 2.18 and 2.18, respectively) (p < 0.05) (SFS: 1.5 and 1.06, respectively) (p < 0.05) (VAS: 2.44 and 2.69 respectively) (p < 0.05). ESWT enhances the effect of BTX-A to a greater extent than ES, probably by modulating rheology of the muscle and neurotransmission at the neuromuscular junction.

Surgical treatment of complex regional pain syndrome type II with regional subcutaneous venous sympathectomy

BACKGROUND

The effectiveness of a new surgical technique for the treatment of severe chronic pain stages was evaluated. For the last 140 years, the treatment of complex regional pain syndrome type II (CRPS II) has been an unsolved problem. Therapeutic approaches have included conventional pain medication, physical therapy, sympathetic blocks, transcutaneous or spinal cord stimulation, injections or infusion therapies, and sympathectomy. When used alone or in combination, these therapies often yield unfavorable results. The majority of physicians who treat patients with CRPS are convinced that a surgical treatment of the affected extremity only exacerbates the symptoms, especially its hallmark excruciating pain.

METHODS

Sixteen patients with a CRPS type II of the upper or lower limb were included in the study after ineffective pain therapy for more than 6 months. The most proximal region of pain associated with CRPS was localized, and 2% lidocaine was injected into that area. Once the sympathetic, deep, burning pain had been blocked, the subcutaneous veins in the previously determined area were surgically removed. A visual analog scale, the Nottingham Health Profile, and physical examinations were used to evaluate the outcome of the operation.

RESULTS

Twelve (75%) surgically treated patients showed significant improvement in limb function, the visual analog scale, and the Nottingham Health Profile.

CONCLUSIONS

These data and recent findings in animal models conclude that CRPS type II is maintained by a coupling of newly sprouted sympathetic and sensible fibers. These fibers can be resected with a regional subcutaneous venous sympathectomy.

LEVEL OF EVIDENCE

Therapeutic study, level III.

Dysautonomia, fibromyalgia and reflex dystrophy

Autonomic nervous system dysfunction observed in fibromyalgia, characterized without exception by a sympathetic hyperactivity and hyporeactivity, has been reported. However, several studies demonstrated reduced levels of norepinephrine and neuropeptide Y at rest and after tilt table in some patients, which was improved by beta-stimulating agents. These findings support heterogeneity in fibromyalgia-associated dysautonomia. Fibromyalgia could be a generalized sympathetic dystrophy since both conditions are activated by trauma and partly linked to sympathetic mechanisms. Yet they differ on several points: hormonal and neurochemical abnormalities are observed in fibromyalgia whereas activation by peripheral trauma and hyperosteolysis are observed in reflex sympathetic dystrophy.

Applied information retrieval and multidisciplinary research: new mechanistic hypotheses in complex regional pain syndrome

Background

Collaborative efforts of physicians and basic scientists are often necessary in the investigation of complex disorders. Difficulties can arise, however, when large amounts of information need to reviewed. Advanced information retrieval can be beneficial in combining and reviewing data obtained from the various scientific fields. In this paper, a team of investigators with varying backgrounds has applied advanced information retrieval methods, in the form of text mining and entity relationship tools, to review the current literature, with the intention to generate new insights into the molecular mechanisms underlying a complex disorder. As an example of such a disorder the Complex Regional Pain Syndrome (CRPS) was chosen. CRPS is a painful and debilitating syndrome with a complex etiology that is still unraveled for a considerable part, resulting in suboptimal diagnosis and treatment.

Results

A text mining based approach combined with a simple network analysis identified Nuclear Factor kappa B (NFκB) as a possible central mediator in both the initiation and progression of CRPS.

Conclusion

The result shows the added value of a multidisciplinary approach combined with information retrieval in hypothesis discovery in biomedical research. The new hypothesis, which was derived in silico, provides a framework for further mechanistic studies into the underlying molecular mechanisms of CRPS and requires evaluation in clinical and epidemiological studies.

Current management of reflex sympathetic dystrophy syndrome (complex regional pain syndrome type I)

Although no major advances have occurred in the curative treatment of reflex sympathetic dystrophy syndrome (RSDS), new pathogenic insights may soon lead to innovative approaches, which may also prove effective in alleviating some forms of neuropathic pain. Preventing nerve compression and ischemia-reperfusion injury constitute valuable measures for preventing RSDS. Vitamin C administration can also prevent RSDS, together with clonidine in high-risk patients. Short-term glucocorticoid therapy has been found effective in preventing RSDS after stroke but has not been evaluated in other situations. Beneficial effects of bisphosphonates have been documented in several placebo-controlled trials. Placebo-controlled trials of ketamine and spinal cord stimulation are in order to confirm or refute the promising results obtained in open-label studies. Mirror visual feedback was introduced recently for the rehabilitation of patients with RSDS but needs to be evaluated in randomized controlled trials.

The Inhibitory Effects of Local Anesthetics on Primary Sensory Nerve and Parasympathetic Nerve in Rabbit Eye

Primary sensory nerves transmit information to both the periphery and central nervous systems, and they mediate neurogenic inflammation by release of neurotransmitters, such as tachykinins, in the periphery. Because the effect of local anesthetics on neurogenic inflammation is a subject of controversy, we investigated the direct effect of local anesthetics on tachykininergic neurotransmission, comparing it with cholinergic neurotransmission in the rabbit iris sphincter muscle. Rabbit iris sphincter muscle is innervated by trigeminal tachykininergic and parasympathetic cholinergic nerves, and the electrical transmural stimulation produces tachykininergic and cholinergic contractions. Cocaine and lidocaine (1-300 microM) attenuated tachykininergic and cholinergic contractions induced by electrical transmural stimulation in concentration- and stimulus frequency-dependent manner. However, the sensitivity to both local anesthetics was slightly, but significantly, higher in tachykininergic than in cholinergic responses. Exogenous neurokinin A and carbachol produced contractions that were not inhibited by 100 microM of cocaine and lidocaine. These results show that local anesthetics have a direct inhibitory effect on tachykininergic neurotransmission of the trigeminal sensory nerve, and the effect on this nerve is more potent than on the parasympathetic nerve and suggests that local anesthetics may have antineurogenic inflammatory effects via the inhibitory effects on the peripheral transmission of primary sensory nerve.

Role of radionuclide imaging in the orthopedic patient

Since its introduction more than 40 years ago, nuclear medicine has played an important role in the diagnosis and detection of soft tissue and skeletal disorders. Skeletal scintigraphy or bone scanning is a diagnostic study used to evaluate the distribution of osteoblastic activity or active bone formation within the body. Because no single imaging technique is ideal in all clinical situations, selecting an appropriate imaging test depends on understanding the pathophysiology of the suspected condition and limitations of each technique. This article provides a brief overview of bone scintigraphy, infection imaging, and positron emission tomography in the context of current, adult orthopedic practice.

Determination of inflammation of reflex sympathetic dystrophy at early stages with Tc-99m HIG scintigraphy: preliminary results

The pathogenesis of reflex sympathetic dystrophy (RSD) is not completely understood. However, an excessive regional inflammation, sensitization of primary somatosensory afferents, and sensitization of spinal neurons are considered to have a role in the pathogenesis of RSD. The underlying pathophysiology relating the clinical picture may help to determine the pharmacotherapeutic approach for an individual patient. Scintigraphy using radiolabelled human polyclonal non-specific immunoglobulin (HIG) has been recognized as a useful tool for the localization of inflammatory disorders. Thirty-six consecutive RSD patients associated with hemiplegia were included in this study. All the patients in this study had three phases bone scan and Tc-99m HIG scintigraphy. On admission, of 36 patients with positive bone scan, 30 had positive Tc-99m HIG scan. All the patients were symptomatic at the time of bone scanning. On the contrary, 24 out of 36 patients subsequently became asymptomatic at an 8-month re-evaluation period. Tc-99m HIG scintigraphy is a non-invasive complementary method for the determination of ongoing inflammatory reactions which also aids the clinicians to predict the response to anti-inflammatory therapy at the very early phase of RSD associated with hemiplegia. This preliminary study may be a source of inspiration for further studies with larger series and longer follow-up .

The Role of Nuclear Medicine in the Evaluation of Complex Regional Pain Syndrome Type I

Chronic pain resulting from complex regional pain syndrome type I (CRPS I), formerly referred to as the reflex sympathetic dystrophy syndrome (RSDS), is a diagnostic challenge to the clinician. It involves multiple organ systems, namely peripheral as well as central nervous, vascular, soft tissue, and skeletal. It usually develops as a consequence of trauma, without nerve injury. Signs and symptoms vary depending on the time since the initiating event, and there is no confirmatory histopathologic diagnosis. This article summarizes the current consensus on the classification, pathophysiology, and diagnostic approaches, emphasizing the role of scintigraphy in the management of this multisystem disorder.

Neuropeptide Y as a far-reaching neuromediator: from energy balance and cardiovascular regulation to central integration of weight and bone mass control mechanisms. Implications for human diseases

PURPOSE OF REVIEW

I review recent knowledge on the interference of neuropeptide Y with energy balance and cardiovascular and renal disease and on the central regulation of bone mass.

RECENT FINDINGS

Although neuropeptide Y is mainly seen as a vasoconstrictor, rats overexpressing the neuropeptide Y gene show reduced blood pressure and longer life span in comparison with control rats. Due to its strong mitogenic effects on vascular smooth muscle cells, neuropeptide Y induces occlusive lesions in a rat model of atherosclerosis induced by balloon angioplasty. The involvement of neuropeptide Y in experimental atherosclerosis is complex and may include also favourable, compensatory, mechanisms because, at physiological concentrations, it also activates a potent neoangiogenic response to ischemia. Subjects with a common genotype in the neuropeptide Y gene, which underlies increased intracellular neuropeptide Y storage, display slightly raised blood pressure, high serum cholesterol and increased carotid intima media thickness. In patients with end-stage renal disease high neuropeptide Y in plasma has been associated consistently with concentric left-ventricular hypertrophy and cardiovascular mortality. Finally, recent studies have shown that neuropeptide Y constitutes an important central regulator of bone mass and that it may be involved in inflammation and immune regulation.

SUMMARY

Evidence has accrued in experimental animals that altered neuropeptide Y is involved in obesity and the attendant metabolic complications. Recent data also suggest that this peptide may play a role in atherosclerosis and related cardiovascular complications.