What is Complex Regional Pain Syndrome?
Complex regional pain syndrome (CRPS) formerly known as Reflex Sympathetic Dystrophy (RSD), is a chronic pain and sensory condition that typically affects the upper and lower extremities (arms and legs). Women are more likely to be affected than men and the disease is most common between the ages of 40-60.
Complex regional pain syndrome (CRPS) is a chronic pain and sensory condition. Over the years, Complex Regional Pain Syndrome has been known by a number of different names including Sudecks atrophy, causalgia, reflex sympathetic dystrophy (RDS), shoulder-hand syndrome, post- traumatic dystrophy, and reflex neurovascular dystrophy.
Complex regional pain syndrome is most frequently seen after trauma to an arm or leg. Other inciting factors include recent surgery, infection, and fractures; all of which can lead to complex regional pain syndrome.
Complex regional pain syndrome can be further characterized as CRPS I and CRPS II. CRPS 1 refers to when pain stems from an initial painful event that did not result in a known nerve injury; whereas CRPS 2 is from an identifiable traumatic event WITH known nerve injury. Each form of Complex Regional Pain Syndrome causes severe, unending pain that cannot be correlated with the extent of the injury.
The two main characteristics seen in patients with CRPS are Allodynia and Hyperalgesia. Other symptoms seen are swelling, skin color changes, change in hair growth, muscle atrophy, and limited range of motion. Allodynia is defined as pain produced by a stimulus that is not usually painful (an example of this would be wind touching your skin and causing pain). In Hyperalgesia, a normally painful stimulus causes much more irritation and pain than would be typically produced. The CRPS effects of allodynia and hyperalgesia are thought to be a development involving both the peripheral nervous system (PNS) and the central nervous system (CNS).
Local tissue injury and inflammation activate the PNS, which sends signals through the spinal cord and to the brain. There is an increase in the excitability of neurons within the CNS, so that normal inputs from the PNS begin to produce abnormal responses. Low-threshold sensory fibers activated by light touch excites neurons in the spinal cord that normally only respond to noxious (painful), or more severe, stimuli. As a result, an input that would normally produce a harmless sensation now produces significant pain. CRPS is most frequently seen after trauma to an arm or leg. Major traumas including car accidents, penetrating wounds, and crush injuries.
Other traumas can include surgery, infection, and fractures; all of which can lead to complex regional pain syndrome. Two types with similar signs and symptoms, but different causes classify complex regional pain syndrome: Type I – CRPS I is a condition of persistent pain and swelling that frequently occurs because of trauma to an area and produces vasomotor disorders (Kandi 2007). This is the most common form. Type II – CRPS II is produced after a direct and specific nerve injury and is much less common.
Women are more likely to be affected than men and the disease is most common between the ages of 40-60. Although the pain can be experiences anywhere in the body, most commonly it affects the distal upper and lower extremities.
Complex Regional Pain Syndrome Symptoms
Prospective studies confirmed an incidence of >10% incidence of CRPS developing in patients after distal radial fractures (Schurmann 2007). Because this disease can be rare, if anyone is suspected of suffering from CRPS it is necessary to be evaluated immediately by a pain physician. Your physician may perform a physical examination demonstrating tenderness over certain areas as well as assessing limitations in movement. The doctor will evaluate the extent of your restricted movements, the amount of pain produced, and the your sensory function. Your physician may also order radiological imaging such as X-Ray, CT scan, MRI, or bone scan depending on their clinical suspicion and the history obtained.
Often beginning in the foot or the hand, Complex Regional Pain Syndrome eventually will begin to cause pain to the related arm or leg. Sometimes, Complex Regional Pain Syndrome will cause pain and spread to the opposite extremity. Some theorize that Complex Regional Pain Syndrome is maintained by the sympathetic nervous system. Others have thought that Complex Regional Pain Syndrome may be linked to an immune response, which would cause the usual inflammatory response of swelling, warmth and a red, rash like representation in the painful area.
With Complex Regional Pain Syndrome, a patient will present two symptoms: allodynia and hyperalgesia. Allodynia can be simply explained as something causing pain that should not, for example, the sensation of your clothing touching your skin causing pain. Most people do not experience pain from that sensation – those with Complex Regional Pain Syndrome would. In hyperalgesia, a patient with Complex Regional Pain Syndrome responds severely to a painful experience, for example, the pulling off of a bandage will cause a momentary sensation of discomfort for those without Complex Regional Pain Syndrome. For a patient with Complex Regional Pain Syndrome, it would cause an excruciating pain sensation.
These abnormal reactions to normal sensations are thought to be caused by accelerated reactivity of neurons within the central nervous system, which in turn causes the normal reactions from the peripheral nervous system to be out of the ordinary. This accelerated reactivity causes an outside stimulus to cause extreme pain in conjunction with what should be a normal stimulus.
Some additional common symptoms include drastic changes in the temperature and color of the skin over the affected limb or body part, accompanied by severe burning pain, skin sensitivity, sweating, and swelling.
Three symptomatic stages have been described in the literature. Staging is not important to clinical management; however it described the disease progression.
Pain is more severe with a burning or aching sensation. The affected area becomes edematous and can have temperature changes.
Edematous tissue becomes indurated. Skin begins to atrophy and occasionally cyanotic. Hair may fall out and the nails become brittle.
Pain spreads proximally. Although it may diminish in intensity, pain remains a prominent feature. Skin further atrophies and becomes friable and shiny without edema. Late in the disease contractures may form.
Complex Regional Pain Syndrome Diagnosis
Complex Regional Pain Syndrome is a very multifaceted pain disorder, which can be very difficult to diagnose and treat. Medical research has not yet determined the single cause of Complex Regional Pain Syndrome, but a number of precipitating factors are linked to the onset of this pain condition. No one specific medical test or tool is currently available to diagnose Complex Regional Pain Syndrome with 100% specificity. Even if a combination of tests is performed, a physician can only state that the symptoms the patient is experiencing are indicative of Complex Regional Pain Syndrome.
The most important key to diagnosing Complex Regional Pain Syndrome is a detailed medical history and physical exam. There are many guidelines and recommendations that describe potential diagnostic criteria. As there is no test to indicate Complex Regional Pain Syndrome, medical tests and exams should still be performed to eliminate other diagnoses. Blood testing can be done to rule out other inflammatory or rheumatologic conditions. Nerve tests should also be performed to be sure the patient does not have peripheral neuropathy or nerve entrapment issues.
Although there is not a solidified diagnostic criteria, common signs and symptoms have been described giving generalized diagnostic parameters for Complex Regional Pain Syndrome. The 3 diagnostic parameters, each with a subcategory, are listed below:
- Motor change
- Range of motion
Although diagnosis is largely done with physical exam and clinical history, other modalities are available in equivocal cases. Standard radiographic findings are normal in as many as 30% of patients. However, they may show osteoporosis as soon as 3-5 weeks of onset.
Complex Regional Pain Syndrome Treatment
Here are a few treatment options for complex regional pain syndrome:
- Sympathetic Nerve Blocks – The procedure involves inserting a small fine needle through the skin to the origins of the sympathetic nervous system. When the nerves are blocked, pain relief can be dramatic for some individuals. Procedures that focus on the face and upper extremities include the Stellate Ganglion Block and Brachial Plexus Nerve Block. Lumbar Sympathetic Nerve Blocks are commonly performed for CRPS in the lower extremities.
- Infusions Techniques- The procedure involves inserting a small catheter through a needle into the epidural space or directly next to affected nerves. Local anesthetic and other medicines are often given through the catheter for extended time periods. When the nerves are blocked continuously with an infusion, pain relief can be dramatic and long lasting.
- Spinal Cord Stimulation – This method involves tiny electrodes being placed within the epidural space close to the spinal cord. The electrodes release a small electrical current to the spinal cord that inhibits pain transmission causing pain relief. In a recent study, ten consecutive active duty United States military personnel with newly diagnosed complex regional pain syndrome underwent early intervention with spinal cord stimulation with favorable results, including decreased pain scores and decreased opioid intake (Verdolin 2007).
- Peripheral Nerve Stimulation – This method involves tiny electrodes being placed close to the affected nerves. The electrodes release a small electrical current that inhibits pain transmission and causes pain relief.
- Medical management – of a patient with CRPS is important and common pharmacologic treatments that are used are membrane stabilizing drugs, NSAIDs, opiate like medications.
- Physical therapy – In order to decrease or prevent functional limitations, physical therapy and occupational therapy are recommended as well as medical treatments (Perez 2007). Physical therapy focuses on exercising the affected limbs, improving range of motion and strength.
- Biofeedback – patients learn to have a better awareness and familiarity with their body. As they learn to relax their body, pain relief is obtained. The psychological component of treatment can work with medical therapies to improve function and decrease the severity of the disease (Breuhl 2006).
- Others – Living with a chronic pain condition can be extremely difficult. People with CRPS have an exceptionally difficult time because others do not understand the amount of pain that they experience. Arizona Pain Specialists are aware of the emotional hardship that you face and can help you relax and de-stress by offering you coping techniques. Some of the methods they offer include therapeutic acupuncture, massage, group therapy, and even prayer.
Dramatic improvements and even remission of complex regional pain syndrome are possible. The sooner treatment is initiated, the more likely dramatic improvements are obtained. Recently, the use of regional anesthetic and nerve stimulating techniques have also been found to be successful in treating CRPS (Perez 2007).
For cases involving an upper extremity, a stellate ganglion block may aid the diagnostic process and may be therapeutic. If a patient sees no results with first-line minimally invasive or conservative treatments, spinal cord stimulation may be indicated.
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Early diagnosis in post-traumatic complex regional pain syndrome Schürmann M, Gradl G, Rommel O. Orthopedics. 2007 Jun;30(6):450-6 PMID: 17598489
Clinical presentation of cutaneous manifestations in complex regional pain syndrome (type 1). Kandi B, Kaya A, Turgut D, Ozgocmen S, Cicek D. Skinmed. 2007 May-Jun;6(3):118-21 PMID: 17478989
Ten consecutive cases of complex regional pain syndrome of less than 12 months duration in active duty United States military personnel treated with spinal cord stimulation. Verdolin MH, Stedje-Larsen ET, Hickey AH. Anesth Analg. 2007 Jun; 104(6):1557-60, table of contents PMID: 17513657
Psychological and behavioral aspects of complex regional pain syndrome management. Bruehl S, Chung OY. Clin J Pain. 2006 Jun;22(5):430-7 PMID: 16772797