Reflex Sympathetic Dystrophy: Causes, Symptoms, Diagnosis

Reflex Sympathetic Dystrophy

Reflex Sympathetic Dystrophy (RSD) is a neuro-inflammatory, chronic condition.  RSD, also known as Complex Regional Pain Syndrome (CRPS), is characterized by a severe burning pain sensation in the extremities (e.g., arms, legs, hands, or feet) caused by damage to the central nervous system (Complex, 2017).  In 1994, the term complex regional pain syndrome was coined during the American Civil War to describe individuals whose pain was out of proportion to their injury (Chang, McDonnell, & Gershwin, 2018).  At the time, CRPS mainly referred to patients with sensitivity and inflammatory symptoms, which developed from periods of immobilization.  In 2003, the May Clinic found CRPS extremely rare (6.28 per 100,000-people per year) (Goh, Chidambaram, & Ma, 2017).  This condition reportedly occurs three times more in women (ages 25 to 40), with an increasing rate of children and adolescents (10 years or older) diagnosed each year (Chang, McDonnell, & Gershwin, 2018).  Also, Chang, McDonnell, and Gershwin (2018) found that 1.16 per 100,000 children between the ages 5 to 15 diagnosed with CRPS recovered 100% through aggressive physical therapy, forced movements of the affected limb, and cognitive behavioral therapy.  RSD remains to be classified as a rare condition in the United States with no cure, but multiple interventions.

Causes of RSD

RSD is categorized into two subdivisions: (1) type I, and (2) type II.  Type I is a form of RSD where the pain is not the result of any nerve injuries or lesions.  Some non-nerve causes for Type I may include infection, blood vessel problem, or entrapment of nerves through an internal injury.  Type I is described as “reflex sympathetic dystrophy,” which comprise of approximately 90 percent (5.46 per 100,000 persons-per-year) of all cases (Goh, Chidambaram, & Ma, 2017).  On the other hand, type II, or causalgia, is diagnosed when severe nerve damage is detected through brain scans (Chang, McDonnell, & Gershwin, 2018).  Nerve damage can occur from a history of trauma or injury (e.g., fractures, sprains/strains, burns, cuts, bruises, limb immobilization, minor medical procedures, or surgery).  Type II occurs at about 0.82 per 100,000 persons-per-year (Goh, Chidambaram, & Ma, 2017).  RSD can arise from a musculoskeletal injury, nerve injury, invasive surgery, or immobilization.  Other precipitating factors of RSD may include certain heart diseases (e.g., myocardial infarction), cervical spine or spinal cord disorders, brain lesions, or repetitive motion disorders that may lead to ailments (e.g., carpal tunnel syndrome) (Reflex, 2019).  Reuben (2004) reviewed a Mayo Clinic study, which found that of the 140 cases of CRPS or RSD, 16.4 percent developed this condition after surgery. The surgeries in this study included 2.3% for arthroscopic knee surgery, 2.1–5% after carpal tunnel surgery, 13.6% after ankle surgery, 0.8–13% after total knee arthroplasty, and 7–37% from wrist fractures (Reuben, 2004).  These surgeries only account for a portion of reasons or causes for RSD in individuals. 

Reflex Sympathetic Dystrophy arises when the nervous system and immune system malfunction as a result of tissue damage from a past traumatic event.  In RSD or CRPS (Complex Regional Pain Syndrome), the affected sensory nerve fibers, or axons, could be unmyelinated or be thinly myelinated, which carry pain messages and signals to the blood vessels (Complex, 2017).  Myelin is a combination of proteins and fat-like substances that insulate the nerve fibers allowing the communication messages to send directly from the brain to the blood vessels (Complex, 2017).  When the nerve fibers experience damage, molecules will secrete out of the hyperactive nerve fibers contributing to inflammation and blood vessel abnormalities, which ultimately contribute to abnormal neurological function in the spinal cord and brain (Pleger et al., 2014; Schott, 2001).  During this process, the nerves misfire, which sends messages and constant pain signals from the brain to the affected area resulting in a tremendous experience of pain.

In addition to nerve damage, the researchers found changes in the central nervous system and brain structures.  Pleger and his colleagues (2014) studied the effects of Type I CRPS or RSD on the brain structure in the prefrontal and motor cortex.  In his study, Pleger and his colleagues (2014) used a magnetic resonance imaging (MRI) machine to find that individuals with chronic RSD demonstrated affected structures in the brain relating to emotional, autonomic, and pain perception regions (Pelger et al., 2014).  Also, Grachev, Thomas, and Ramachandran (2002) conducted a positron emission tomography (PET) study of individuals with chronic pain to explore the effects on the regions of the brain.  They implanted electrodes in the left ventroposterior medial thalamus, which is a large mass of gray matter on the dorsal side of the brain, which relaying sensory signals such as motor signal, and consciousness and sleep regulation (Pelger et al., 2014).  In this region, the researchers found a significant increase in blood flow in the prefrontal cortex after stimulation. This finding suggests that there is a differentiation of the neuronal network for chronic pain versus acute pain (Grachev, Thomas, & Ramachandran, 2002).  These researchers also found that individuals with CRPS or RSD experienced prefrontal hyperactivity through an fMRI.  This region is mainly responsible for the pathophysiology of mood and anxiety.  Grachev, Thomas, and Ramachandran (2002) also explored the involvement of the prefrontal cortex as a stress-related affective response to perceive negative emotions.  The effects on the prefrontal cortex in the brain may explain the intense experience of pain reported by individuals with CRPS or RSD.

Individuals with RSD experience persistent pain, mainly in their extremities, which results in decreased daily functioning. In 1997, Melzack and Torgerson invented a questionnaire to identify common language to describe the experience of pain, as well as a standard rating scale for the level of intensity of the pain they were current experiencing (Melzack, 2005). The McGill Pain Questionnaire (MPQ) is a multidimensional 84-item self-report questionnaire intended to assess pain symptoms (Melzack, 1975). The MPQ contains approximately 20 subcategories of verbal pain descriptors based on sensory (e.g., skin color, temperature changes, pressure, sensitivity), affective (e.g., tension, fear, autonomic properties), and evaluative domains, as well as pain intensity levels (McGill, 2017). The average testing time for the MPQ is 15 to 20 minutes for the initial assessment and 5 to 10 minutes when the individual gets re-evaluated.  This questionnaire and index scale are the preferred pain assessments according to the Reflex Sympathetic Dystrophy Syndrome Association (RSDSA) (McGill, 2017). Currently, the MPQ is the most frequently used pain assessment instrument around the world.

One of the significant traits of RSD is that the pain appears to be constant and more significant than the event that initially caused it. The individual’s level of pain can be rated on a McGill University Pain Index. In addition to the McGill Scale Questionnaire, McGill University created a pain index that measured the intensity and level of pain across several medial conditions. Some of the other medical conditions include a fracture, phantom limb pain, non-terminal cancer, childbirth, and finger amputation. On the scale, CRPS or RSD is labeled as Causalgia, which is Latin for “burning pain” (). Typically, RSD pain level measures about a 45 out of 50 on the McGill Pain Scale, which measures above all of the previously listed conditions. This index is a valuable assessment tool that can be used in many languages by various health professionals across the world.  The McGill Pain Questionnaire and Index allow individuals to have a common language to describe their pain and intensity.

Signs and Symptoms

Every sign and symptom of CRPS can vary from person to person, depending on their type of CRPS.  RSD can affect multiple parts of one’s body but mainly focus on an individual’s extremities (e.g., shoulders, arms, hands, fingers, hips, legs, knees, feet, and toes) (Luo, 2017).  Some of the signs or symptoms of RSD that occur in the extremities include skin color changes, skin temperature, hair or nail growth, swelling or sweating in the affected area, and limited range of motion (Luo, 2017).  Additionally, the symptoms may become detrimental as one’s hair and nails might change, as well as experiencing deterioration or atrophy in their muscles or bones (Reflex, 2019).  Many of these symptoms can intensify the level of pain experienced by the patient.  The individual may experience pain in several ways.  One experience of pain is described as deep, aching, cold, burning, or increased skin sensitivity (Telltale, 2019).  Another aspect of pain symptom is hyperalgesia or allodynia.  Hyperalgesia is a heightened sensitivity to pain stimulation, whereas, allodynia is pain from a non-painful stimulus (e.g., shower, or touch of clothing) (Telltale, 2019).  The pain experienced by the patient is typically described as ‘out of proportion to the initial injury.’  Even though an individual may experience a variety of symptoms, chronic pain is the main symptom of RSD.  Every individual with RSD/CRPS may or may not experience all of the typical signs or symptoms.

Symptoms may occur all at once or through three stages.  There are three stages of symptom development.  Stage One typically lasts one to three months.  During stage one, or acute stage, the individual may develop the following symptoms changes in skin temperature, switching between warm or cold, faster growth of nails and hair, muscle spasms and joint pain, severe burning, and aching pain that worsens with even the slightest touch or breeze (Reflex, n.d.; Shiel, 2018).  Continually, skin can become blotchy, purple, pale or red, swollen, or sweaty based on the changes in the body.  Stage two, or dystrophic, lasts from three to six months include changes in the skin, cracked or easily breakable nails, slow hair growth, stiff joints, and weak muscles resulting in an increased intensity of the pain (Reflex, n.d.; Shiel, 2018).  Finally, stage three, or atrophic, involves more severe symptoms including tightened muscles and tendons (contracture), muscle wasting, and pain in the entire extremity resulting in limited movement or mobility (Reflex, n.d.; Shiel, 2018).  Once an individual reaches stage three, the symptoms become irreversible.  Additionally, an individual may experience depression or anxiety if they experience severe or long-lasting pain.  Early diagnosis and treatment are critical to slow the progression of symptoms for individuals with RSD.

Diagnostic Criteria

As there are no single diagnostic tools for RSD/CRPS, there are a variety of scans or tests that can detect irregularities in the body.  A doctor should rule out other medical conditions that may cause similar symptoms (e.g., blood clots, or a spreading cancer tumor which can cause pain and swelling) (Reflex, 2019).  Once a doctor rules out other causes or conditions, the McGill Pain Index can measure pain intensity as a diagnostic tool.  A diagnosis of RSD/CRPS is made after an evaluation to establish any trauma, recent injury, disproportionate pain, and other symptoms (i.e., swelling, impaired movement, changes in tissue growth, and abnormal function of the sympathetic nervous system) (Reflex, 2019).  The International Classification of Disease (ICD-10) characterizes the RSD diagnostic criteria based on Type I or Type II CRPS and the location of the pain.  The ICD-10 codes for RSD include (G90.5 Complex Regional Pain Syndrome Type I (CRPS I); G90.50 Complex Regional Pain Syndrome Type I, unspecified; G56.4 Complex Regional Pain Syndrome II of the upper limb; G57.70 Complex Regional Pain Syndrome II of the unspecified lower limb) (ICD-10, 2018).  There are varying ICD-10 diagnoses and methods to detect irregularities representative of an RSD or CRPS diagnosis.

Some types of brain scans utilized to detect nerve damage include bone scans, MRI, and X-ray scans.  A bone scan would be used to identify wear or deterioration on the bones or accumulation of calcium in the bloodstream (de Vaugelade, 2016).  As a symptom of RSD, the bones can begin to deteriorate the affected area.  During this bone scan, a radioactive substance would be injected into the veins of the affected limb, allowing a specialized camera to view the bone tissue and potential damage (de Vaugelade, 2016).  Another method to diagnose is through thermography, a sympathetic nervous system test.  This test measures skin temperature, and blood flow identifies the difference between healthy and unhealthy limbs (Jeong, Yu, & Chung, 2013).  MRI scans and X-rays are additional tests that can detect irregularities within the body. An MRI scan can display tissue irregularities near the affected body parts.  Also, an X-ray detects abnormalities or mineral loss in the bones of the affected areas.  No injection of radioactive materials is necessary as X-rays utilize strong radioactive waves, and an MRI utilizes strong magnetism (Christo, 2015).  The final test that could determine an RSD diagnosis is an electrodiagnostic test.  Electrodiagnostic tests are used to determine the presence of nerve damage (Reflex, 2017).  For example, some electrodiagnostic tests inject a small needle into the muscle groups to send mild electric shocks to assess damage or deterioration (Tamburello, 1992).  This method would detect damaged nerves; however, it may cause more severe pain throughout the process.  Some individuals experience the symptoms of pain with a technique for relief.

Interventions

Early intervention is crucial for those with Reflex Sympathetic Dystrophy (RSD).  As RSD displays mainly as a physical disorder, studies have shown that people exaggerate their pain or symptoms for psychological reasons.  The progress of undiagnosed RSD signs and symptoms may result in atrophy, tissue wasting, or contracture, muscle tightening.  Atrophy is the deterioration or weakening of an individual’s skin, bones, and muscles resulting from immobility or stiffness in one’s arms or legs due to pain (Complex, 2018).  On the other hand, contracture is the experience of one’s muscles, especially hands, fingers, feet, or toes contract into a fixed position (Complex, 2018).  There is a high probability of remission through early diagnosis and quick implementation of appropriate treatment.

As there is no definitive cure for RSD, there are treatment options to lessen the perception and level of pain for the individual.  One method is rehabilitation or physical therapy.  Physical therapy implements an exercise program for the affected limb to increase blood flow and lessen circulatory symptoms (Complex, 2017).  Exercise is also noted for improving flexibility, strength, and function of the affected limb, as those with pain may tend to inhibit or restrict movement in that area until the pain subsides.  These rehabilitating methods work with the brain changes to prevent or reverse chronic pain progression (Barnhoorn et al., 2015).  Moreover, occupational therapy teaches specific techniques and new ways of performing daily tasks to improve overall functioning.  In addition to physical treatment, psychotherapy can be used to help people learn cognitive techniques to decrease their perception of pain.  In therapy, the individual can learn methods like progressive muscle relaxation, guided imagery, and mindfulness as a way to help minimize the perception of pain during a painful episode.  As a treatment option, there are a variety of medications available to inhibit the experience of pain. For example, a non-steroidal anti-inflammatory drug (e.g., aspirin, ibuprofen, and naproxen) can treat moderate pain (Complex, 2017).  Some medications used were once focused on the treatment of seizures or depression but may have a substantial effect on neuropathic pain as in RSD (e.g., gabapentin, pregabalin, amitriptyline, nortriptyline, and duloxetine) (van de Vusse, Stomp-van den Berg, Kessels, & Weber, 2004).  Gabapentin, also known as Neurontin, has displayed advances in treating individuals with RSD with no fatal overdose or organ failure (van de Vusse, Stomp-van den Berg, Kessels, & Weber, 2004).  Gabapentin is one medication that was previously used for seizures but now serves to normalize overactive pain conditions to reduce pain (Taylor et al., 1998).  Medicine is not the only method to normalizing or reducing pain for patients with RSD.

There are alternative intervention methods for nerve stimulation and pain reduction.  One option is a sympathetic nerve block, which involves the injection of an anesthetic near the spinal cord to block the activity of the sympathetic nerves and increase the flow of blood in that area (Complex, 2017).  Even though patients have reported temporary relief from pain, but there is no evidence of long-term relief.  Another option is a spinal cord stimulation that uses needles to stimulate electrodes near the spinal cord to provide a tingling sensation in the affected or painful region of the body (Visnjevac et al., 2017).  These electrodes may be placed temporarily or for a few days to assess the effectiveness of the individual.   Through this method, the electrodes are implanted through minor surgery.  The implant would include the stimulator, battery, and electrodes under the skin on the torso region (Complex, 2017).  An external controller can be used to turn the stimulator on and off once it is implanted in the body.  Studies report that approximately 25 percent of individuals require additional surgery due to equipment malfunctions (Complex, 2017).  As this method may be invasive, there are other non-invasive interventions.  With every advance in technology and knowledge about RSD, researchers are exploring new treatment options.

Conclusion

Reflex Sympathetic Dystrophy (RSD) is still considered a rare, chronic neuro-inflammatory condition that is characterized by a burning pain in the individual’s extremities.  RSD mainly affects more women than men ages 25 to 40 years-old and is becoming increasing more prevalent in children and adolescents (ages 10 years or older).  Individuals with RSD experience more intense pain that the initial injury.  There is no current cure for RSD or Complex Regional Pain Syndrome (CRPS), but there are a variety of interventions that may reduce the intensity of pain, stimulate the damaged nerves, or increase blood flow to the affected extremities.  Every patient will respond to different interventions based on their symptoms and intensity of pain.  As some patients may respond well to psychotherapy session, other patients may require more invasive interventions such as spinal cord stimulation.  It is most important that every patient receives early diagnosis and intervention to slow the progression of symptoms.  The Reflex Sympathetic Dystrophy Syndrome Association (RSDSA) and the National Institute of Neurological Disorders and Stroke (NINDS) are continually researching new methods to treat individuals with RSD or CRPS.  Current research is exploring the benefits of biofeedback therapy, intravenous immunoglobulin (IVIG), and graded imagery for symptom reduction in individuals with RSD (Abbott-Fleming, 2019; Lofland, 2019).  For example, through graded motor imagery, the individuals would perform mental exercises by having the individual identify pain regions on contralateral sides of the body which looking in a mirror and visual moving these extremities mentally, not physically (Abbott-Fleming, 2019).  All of these interventions are methods to stimulate the nerves, increase blood flow, and decrease pain for the individual.  Early intervention can increase the probability that the symptoms may go into remission.  There is no cure for Reflex Sympathetic Dystrophy (RSD), but there are methods to help individuals continue to live a functioning and healthy life. 

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