Reflex sympathetic dystrophy (RSD) is a condition that is often described under various synonyms that point to its incompletely understood etiology. In 1864, Weir Mitchell coined the term causalgia to designate severe pain following nerve injury. In 1900, Sudeck described regional demineralization accompanying posttraumatic pain. In 1923, Leriche described vasomotor disequilibrium. In 1947, Evans introduced the term reflex sympathetic dystrophy.
In 1993, the International Association for the Study of Pain (IASP) renamed algodystrophy complex regional pain syndrome (CRPS; also known as chronic regional pain syndrome). RSD is type 1 CRPS. It can be considered an excessive sympathetic reaction of joints and periarticular soft tissues to any insult, traumatic or unknown.[1] This is quite different from causalgia (type 2 CRPS), in which the etiology is a partial nerve injury.
RSD is characterized by pain, regional edema, joint stiffness, muscular atrophy, vasomotor disturbances (including temperature changes), trophic skin changes, and regional skeletal demineralization seen on radiographs. These changes are aggravated by activity and extend over a larger area than the primary injury or surgery, including the area distal to this focus.[2, 3]
Because pathognomonic criteria are lacking for RSD, a taxonomic system based on clear definitions and objective quantification is desirable. Therefore, the current terminology of CRPS is increasingly being used as an umbrella to replace the myriad empirical descriptions used previously. No apparent relation exists between the degree of initial trauma and the severity of RSD, but RSD generally is more frequent following minor trauma or operations.
RSD usually follows minor trauma or surgery. It also has been associated with various clinical conditions (eg, diabetes, parkinsonism). It begins with spontaneous pain associated with vasomotor and sudomotor disturbances.
Bonica described the progress of severe cases of RSD in three stages, as follows[4] :
Iatrogenic causes of RSD following surgery, such as carpal tunnel decompression or Dupuytren release, can be diagnosed easily.[5] No clear etiology (including trauma) can be identified in 25-35% of cases. A detailed history can be useful to pinpoint uncommon causes of RSD.
Potential causes of RSD include the following:
Reflex sympathetic dystrophy following surgery for Dupuytren contracture.
Possible contributory causes include the following:
Statistically significant associations include the following:
According to various researchers, the incidence of RSD may be 2-17% following minor trauma or surgery. If causalgia is included in the broad definition, the incidence can be as high as 32-35%. In the past, many subtle forms of RSD were missed, but with increased awareness of the condition, actual incidence may be much higher than initially thought.
Worldwide, no regions or population groups have been demonstrated to have a predilection for RSD.
Most patients with RSD are aged 30-55 years; the mean age is 45 years. With increasing awareness, RSD is being diagnosed in children more often; however, no studies exist pointing to a particular age distribution.
RSD is more common in women than in men; the male-to-female ratio is approximately 3:7. The ratio of upper-extremity to lower-extremity involvement is approximately 2:1. Even in children, girls are affected more frequently than boys, but peculiarly, the lower extremity is involved more frequently than the upper extremity.[10]
No particular race has a predilection for RSD.
Mortality associated with RSD is negligible, though morbidity is extremely high. About 80% of patients with RSD diagnosed within 1 year of injury improve significantly. However, 50% of patients with untreated symptoms lasting more than 1 year have profound residual impairment. Timely diagnosis is important for minimizing the risk of progression toward chronic disease.[11]
Despite good results following intravenous sympathetic blockade and intensive mobilization techniques, weakness of the extremity resulting from RSD is seen in almost 50-65% of patients, even 18-24 months after the initial diagnosis. Full range of movement accompanying the above aggressive therapies is seen in 60-74% of patients. Prolonged morbidity is observed in about 50% of patients with psychiatric diathesis, workers' compensation claims, and lawsuits.[12]
Emphasize to all patients the importance of early and supervised mobilization of the affected part. Give patients a list of plaster instructions and a list of realistic goals to be achieved within a specified time interval. Any lag in achieving these objectives due to pain, swelling, or other causes should inspire concern leading to early diagnosis and institution of treatment.
Patients with reflex sympathetic dystrophy (RSD; also referred to as complex regional pain syndrome [CRPS] type 1) have a history of trauma, minor rather than major (eg, Colles fracture), in about 50-65% of cases.[13] The condition may also follow a surgical procedure (see the image below).
Reflex sympathetic dystrophy following surgery for Dupuytren contracture.
Symptoms and signs of RSD include the following:
Trophic changes (occurring within 10 days of onset of RSD in 30% of the extremities affected) include the following:
Changes in autonomic function[14] include the following:
The Budapest criteria are commonly used to diagnose CRPS (other criteria are also used). According to these criteria, a diagnosis of CRPS requires that a patient report at least one symptom in three of the following four categories:
In addition, on clinical examination, at least one sign must be present in two or more of the following categories:
Finally, it must be the case that no other condition is present that can explain the signs and symptoms observed.
No screening tests exist for complex regional pain syndrome (CRPS); accordingly, all inviduals with suspected CRPS should undergo diagnostic assessment by a clinician.[15] Diagnostic tools validated for use in adults include the Veldman criteria, the Internation Association for the Study of Pain (IASP) criteria, the Budapest criteria, and the Budapest research criteria; no diagnostic tools have yet been identified for pediatric patients.[15]
Other problems to be considered in the differential diagnosis include the following:
Soft-tissue swelling and regional osteopenia may be present in patients with reflex sympathetic dystrophy (RSD; also referred to as complex regional pain syndrome [CRPS] type 1). Regional osteopenia is evident on plain films in 80% of extremities (see the image below).
Radiograph of affected extremity, depicting regional osteopenia contrasted with normal radiographic appearance of the opposite extremity.
The following five radiographic patterns were described by Genant et al[16] :
Three-phase technetium-99m scanning is commonly used. Scan findings are considered positive if flow is asymmetric in phases 1, 2, and/or 3. Bone scans do not correlate with symptoms or provide prognostic information.
In a study by Im et al, diffusion tensor imaging was used to assess the structural integrity of prefrontal white matter in CRPS patients and patients without CRPS, and the degree of pain catastrophizing was assessed in the CRPS patients.[17] The CRPS patients had lower structural integrity in the prefrontal cortext, and lower structural integrity was correlated with a higher degree of pain catastrophizing.
Other tests to be considered include the following:
Tests under investigation include the following:
Questionnaires used for subjective complaints of pain include the following:
CRPS patients may exhibit visuomotor impairments during pointing tasks.[19]
The quantitative sensory axon reflex test (QSART) is sometimes used for evaluation of sudomotor function in the diagnosis of CRPS, but a study by Lee et al found it to be of low diagnostic value for either screening or confirmation.[20]
The tourniquet ischemia test has not been frequently used for the workup of suspected CRPS but may be useful for confirmation in patients who meet the clinical criteria for the diagnosis.[21]
Because RSD is a condition that seldom is treated surgically, histopathologic descriptions are rare.
Pathologic findings from osteonecrotic femoral head specimens have been studied extensively on the basis of intramedullary pressures (IMP) and intraosseous phlebography.
The gross appearance is as follows:
The microscopic appearance is as follows:
The triphasic course of vasomotor instability has been used to stage RSD, as follows:
The goals of treatment of reflex sympathetic dystrophy (RSD; also referred to as complex regional pain syndrome [CRPS] type 1) are as follows[22, 23, 24, 13] :
Management approaches include the following:
Prophylactic oral administration of vitamin C may reduce the incidence of CRPS after wrist fractures. Zollinger et al recommended a daily dose of 500 mg for 50 days.[28] Alimian et al found that giving vitamin C 500 mg for 6 weeks significantly reduced the incidence of CRPS after distal radius fractures.[29] Prophylactic vitamin C may prove useful in other settings as well. Jacques et al found that vitamin C 1 g for 40 days reduced the risk of CRPS after total knee arthroplasty.[30]
Pharmacologic agents used are classified as follows:
Various routes of administration for pharmacologic interventions include the following:
In using sympathetic blockade, the presence of allodynia and hypoesthesia are negative predictors for success. The use of sympathetic blocks as treatment for RSD (CRPS 1) should be considered carefully between potential success and possible adverse effects. The procedure is as likely to cause a transient increase in pain as a decrease in pain. Patients should be warned about this symptomatology.[32]
The following nonpharmacologic and nonsurgical therapies may be useful[33, 27] :
Other interventions include the following:
Surgical/ablative therapies include the following[25] :
Some evidence suggests that interventional techniques (eg, radiofrequency [RF] treatment) may prove useful for alleviating pain in sympathetically mediated pain conditions such as CRPS,[38] though additional data from randomized controlled studies are needed to determining the place of such techniques in clinical practice.
Intensive physical therapy following a successful sympathetic blockade is key to faster rehabilitation in patients with RSD.
IV blocks with rigorous mobilization techniques must be implemented early in the treatment process for RSD.
Active and passive mobilization and heat and cold modalities all have been used with good effect in RSD, acting via the gate theory. The gate theory suggests that a finite amount of information can be received at the spinal cord or at the cortical level. The gate is the dorsal horn of the spinal cord. Therefore, painful stimuli, if displaced or modified by less noxious stimuli, cannot be processed through the gate.
Most cases of RSD in orthopedic practice can be prevented through early detection and early treatment. In most cases, a possible cause can be identified, such as overly tight bandages or plasters, a limb improperly splinted, or neglect of active movement of the part. The treating physician should be aware of and alert for compression syndromes of the underlying nerve or for swelling and pain resulting from a displaced bone fragment. The mainstay of treatment is mobilization of the affected part.
In patients with reflex sympathetic dystrophy, the goals of pharmacotherapy are to reduce morbidity and prevent complications.
Suppress sympathetic nerve function / noradrenaline inhibitor.
Inhibits vesicular uptake of noradrenaline and thus stops excitation of sympathetic nervous system; inhibits beta-hydroxylation of dopamine to noradrenaline.
Lewis et al reported good results in 90% of patients at 18 months, with 93% of patients experiencing pain relief.
May exert effect by causing blockade of postganglionic synapses.
May have effect through long-lasting noncompetitive alpha-adrenergic blockade of the postganglionic synapses in smooth muscle.
Alpha-1 and alpha-2 adrenergic blocking agent that blocks circulating epinephrine and norepinephrine action.
May act to decrease muscle tone.
Stimulates alpha2-adrenoreceptors in brain stem, activating an inhibitory neuron, which in turn results in reduced sympathetic outflow.
Acts on postganglionic fibers at the presynaptic level, releasing noradrenaline and inhibiting reuptake and rerelease. Fiscat et al reported good results in 63% of cases; Bensigner et al reported good results in 58.6% of cases.
For administration, IV access is gained as close as possible to the involved part. A BP cuff is tied well above the site of pain and inflated above the systolic pressure; a second BP cuff is tied below the first cuff as in a Bier block. Pressure is maintained for 20 min, the limb manipulated, and pressure is reduced while alternating between the 2 cuffs.
Six blocks are performed on alternate days with rigorous rehabilitation; repeated blocks even if the first block fails.
Inhibit calcium ions from entering slow channels; select voltage-sensitive areas, or vascular smooth muscle.
May have a relaxant effect on certain muscles. Inhibits transmembrane influx of calcium ions into smooth muscle, which, in turn, inhibits contraction of the muscle fibers.
May have a relaxant effect on certain muscles. Inhibits transmembrane influx of calcium ions into smooth muscle, which, in turn, inhibits contraction of the muscle fibers.
Have anti-inflammatory properties and cause profound and varied metabolic effects. Corticosteroids modify the body's immune response to diverse stimuli.
Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reducing capillary permeability.
Local anesthetics stabilize the neuronal membrane and prevent the initiation and transmission of nerve impulses.
Decreases permeability to sodium ions in neuronal membranes. This results in the inhibition of depolarization, blocking the transmission of nerve impulses.
A complex group of drugs that have central and peripheral anticholinergic effects and sedative effects. They have central effects on pain transmission. They block the active reuptake of norepinephrine and serotonin.
Analgesic for certain chronic and neuropathic pain.
Pain control is essential to quality patient care. Analgesics ensure patient comfort, promote pulmonary toilet, and have sedating properties, which are beneficial for patients who experience pain.
Binds to opiate receptors in CNS, causing inhibition of ascending pain pathways, altering perception and response to pain.