CRPS in Children

Overview
Stages of CRPS
Fast Facts
Myths and Misconceptions
How CRPS Occurs
Disease Types
Treatment Options
Psychological Treatment for Pediatric Pain
Conclusions
References
Annotated Bibliography

Overview

Complex regional pain syndrome (CRPS) includes several recognized neuropathic disorders (i.e., disorders that cause changes to nerves and the central nervous system): Before 1993, CRPS type I and CRPS type II were known as reflex sympathetic dystrophy (RSD) and causalgia.¹

Your child's physician may diagnose CRPS if your child experiences the following criteria at some point:

• an injury or trauma
• continuing pain where normal light touch or temperature change leads to pain, called allodynia, or an increased response to pain after the event, called hyperalgesia
• abnormal sweating (sudomotor activity) at some point in the painful region
• no other coexisting conditions or diseases that could explain the cause of the pain

The physician will diagnose CRPS type I if the child experiences spontaneous pain, increased response to pain after the initial event (hyperalgesia) or temperature changes leading to pain (allodynia) plus at least two of the above elements. A CRPS type II diagnosis will be made if the child experiences an injury or trauma, abnormal sweating, and has not other diseases of conditions that could explain the pain.^3,4

The pain a child with CRPS feels does not follow the route of a particular nerve. CRPS typically affects the most distal part of the limb such as the toes and foot or fingers and hand. There are cases where the pain can spread upward affecting the entire limb. If your child is diagnosed with CRPS type I, it means he or she has not suffered a nerve injury and experiences pain out of proportion to the initial injury. Most children with CRPS present with a history of minor trauma or repetitive strain type injury.² A simple trip or fall can lead to the onset of CRPS. In CRPS type II, there is known nerve injury.

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Stages of CRPS

Not all people with CRPS move from stage to stage in an orderly progression, especially not children. Stage one is called the acute stage. The child's onset of CRPS may occur immediately after the initial injury or may not occur until several weeks after the event. Either way, the child experiences pain that is out of proportion to the injury. Your child may have swelling (i.e., edema), redness or inflammation of the skin (i.e., erythema) and increased warmth; however, some children initially may have a cool extremity. Stage two is called the dystrophic stage and typically occurs three to six months after symptoms begin. You may notice skin and nail bed changes in your child during this stage and your child's physician may find bony demineralization by taking radiographic images. The third stage of CRPS is called the atrophic stage where a progressive decline of skin and muscle and osteopenia (i.e., a condition in which bones are not mineralized normally) can occur. Children seldom progress to the atrophic stage although stage three is not unheard of in children.

It is not known how many children have CRPS type II (i.e., causalgia) – researchers estimate that 1% to 5% of the adult population has CRPS type II.⁴ Children may develop CRPS type II from subtle but direct nerve injury as occurs with improper needle injections or catheter placements or trauma caused by heavy machinery accidents (e.g., lawn mower). Children who have CRPS type I more frequently are affected in one of their lower extremities – children's lower extremities are affected about five times more often than upper extremities.² Adults, on the other hand, are twice as likely to be affected in an upper extremity. There are twice as many adult female cases as there are male cases of CRPS type I.5 In children, there is a sharper contrast as the syndrome occurs in girls four times more often than in boys. Average age of onset of the syndrome is 12.5 years.² Most children with CRPS type I are from upper middle class families and are athletic. A typical pediatric patient with CRPS type I is a female who participates in ballet, soccer or gymnastics. Researchers have hypothesized that there may be a genetic predisposition to CRPS type I. Most children who have the syndrome are Caucasian. ^5,6

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Fast Facts

• CRPS type I (reflex sympathetic dystrophy [RSD]) occurs in girls four times more often than in boys.
• A lower extremity (leg, knee, ankle, foot) is more likely to develop CRPS type I than is an upper extremity.
• Most children with CRPS type I are about 12 years of age, but the syndrome can occur in younger children.
• CRPS type II can occur at any age.
• The pain of CRPS type I usually occurs weeks to months after the initial injury; however, immediate onset of neuropathic pain has been documented.
• The pain of CRPS often is described as sharp, shooting, stinging, burning, vibrating, deep, or tingling.
• The distal part of the limb (hand or foot) most often is affected and is cold or hot to the touch when compared to the unaffected side.
• Physical therapy is key to controlling the syndrome.
• Children seem to do equally well with oral medicines as compared to more invasive techniques such as intravenous (IV) local anesthetic and other regional blocks.
• Most children with CRPS type I are active in sports and have mild trauma that they may not even remember. Cases of CRPS type II result from major traumatic accidents and injury to the nerve.

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Myths and Misconceptions

Myth: If a patient does not respond to a local anesthetic regional or sympathetic block, then it must not be CRPS type I.
Fact: It is clear that all children do not experience the disorder in the same way. The sympathetic nervous system may play a larger role in some cases and this is called sympathetically maintained pain (SMP). In cases where there are some autonomic signs but no response to sympathetic challenge, then the pain is described as sympathetically independent pain (SIP).

Myth: CRPS is rare.
Fact: Although the actual prevalence is unknown, CRPS is not a rare disorder. According to the Reflex Sympathetic Dystrophy Syndrome Association of America (RSDSA), CRPS may affect millions of people in the United States. Unfortunately, because symptoms vary so widely many people are not quickly diagnosed with CRPS.

Myth: Doctors know what causes CRPS.
Fact: No one knows what causes CRPS. However, a number of factors have been associated with it, including trauma, heart attack, cervical spine or spinal cord disorders, cerebral lesions, infections, surgery, and chronically painful disorders such as Carpal Tunnel Syndrome.

Myth: CRPS is a newly discovered disorder.
Fact: CRPS-I has been called a variety of names for nearly 140 years. Today, the disorder is most commonly referred to as Reflex Sympathetic Dystrophy Syndrome (officially called CRPS I) or Causalgia (officially called CRPS-II). Lesser known names include Sudeck's Atrophy, Post-Traumatic Dystrophy, Shoulder-Hand Syndrome, and Reflex Neurovascular Dystrophy.

Myth: Minor injuries do not cause CRPS.
Fact: Not true. Even commonplace injuries such as a sprained ankle or a fall can cause CRPS, as can surgery. CRPS can start immediately after the injury or up to weeks later, if there is something – such as an undiagnosed fracture – that is causing persistent pain. There are even reports of "spontaneous" CRPS unrelated to any apparent illness or injury.

Myth: Pain from CRPS is not nearly as bad as patients claim it is.
Fact: Absolutely untrue. Severe, constant, burning pain close to the injured area or in one or more extremities, such as an arm, leg or foot, is among the first CRPS symptoms. What is unusual about CRPS is that the pain people experience is far greater than what normally would be expected after an injury. The pain then spreads beyond the area of the original injury.

Myth: People with CRPS suffer no symptoms except pain, swelling, heat or coldness in the injured area and occasionally a change of skin color.
Fact: Some people with this disorder endure many other aggravating symptoms. These include movement disorders such as muscle spasms, tremors, weakness, fatigue and a variety of emotional problems, including anxiety and depression. Inability to work or play effectively also creates social problems, such as loss of important role functions, and misunderstanding on the part of family members, employers, acquaintances and even health-care providers.

Myth: CRPS cannot spread throughout the body.
Fact: In about 70 percent of people, CRPS does spread, at least locally (in which case it becomes a "regional" disorder). In about 20 percent of cases, pain spreads into other limbs.

Myth: CRPS will disappear within six months.
Fact: Unfortunately, CRPS can become a chronic problem for many people, although spontaneous remissions sometimes occur. Many Pain Medicine specialists believe that early, vigorous treatment within the first six months of diagnosis offers the best chance of controlling or curing the disorder. Such treatment includes aggressive pain control with physical therapy, with emphasis on activation of involved limbs. A delay in treatment or inactivity increases the risk that CRPS will become a long-term, chronic disorder. Normal use of the limb is the best therapy.

Myth: Everyone with CRPS should get the same type of treatment.
Fact: Each CRPS patient needs an individual treatment plan. While some medications and therapies may help one person, they won't necessarily aid another. One "size" does not fit all!

Myth: Any physician can treat CRPS without additional consultation from colleagues.
Fact: Experience in treating a specific disorder is always important. Because CRPS is a complex condition with varying degrees of severity and associated disability, a team approach to treatment is critical. In addition to a physician trained in Pain Medicine, the CRPS treatment team might include a physical therapist, psychologist, social worker and others. Having a qualified physician in charge of the team helps prevent medical duplications, serious medical omissions or contradictory treatment instructions.

Myth: Narcotics do not help relieve CRPS-related pain.
Fact: Narcotic medications can be effective in many patients. Physicians use these medications when non-narcotic pain relievers are not effective and before considering invasive treatment such as surgery or spinal cord stimulation. (See CRPS treatment options.) Narcotics also are used to reduce the level of pain so that other forms of treatment, such as CRPS physical therapy, can be administered without causing additional discomfort. Pain Medicine physicians favor the use of long-acting narcotics taken on a regularly timed, rather than "as-needed," basis. Although narcotics are subject to a great deal of misunderstanding, such drugs can be used for legitimate medical reasons with little fear of addiction. However, tolerance can develop with long-term use and a patient may require increasing doses for pain control. This can lead to undesirable side effects.

Make sure your physician is very familiar with the use of narcotic drugs before taking them for pain management. The bottom line is that narcotics are useful only if they help promote an increase in physical activity along with offering some pain relief.

Myth: CRPS occurs in psychologically unbalanced people.
Fact: Absolutely untrue. People who develop CRPS are psychologically no different than the rest of the population. At times, when someone endures months of constant, undiagnosed pain, he or she can become depressed or suffer other psychological changes. However, when CRPS symptoms are relieved, these problems typically disappear.

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How CRPS Occurs

Researchers and physicians do not fully understand why CRPS occurs; however, there are a number of precipitating factors are linked to the syndrome – in particular, trauma. Biochemical changes at the initial site of injury and then later within nerves, spinal cord and brain may all play a role in the development and continuation of CRPS. Hopefully, continued research will one day identify these mechanisms and lead to more effective CRPS treatments.

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Disease Types

CRPS type I: sometimes is still known as reflex sympathetic dystrophy or RSD. Symptoms of the syndrome include continuing pain that seems disproportionate to the initial cause, extreme skin sensitivity in the painful area, and other symptoms associated with CRPS, such as altered skin blood flow indicated by skin discoloration, and edema or swelling caused by fluid retention.

CRPS type II is also known as causalgia where there is a known cause and evidence of nerve injury. In CRPS type II, there is known nerve injury. Children with CRPS type II generally have experienced a crush trauma as occurs in a motor vehicle accident or in farm and yard equipment accidents. Subtle but direct nerve trauma with needles and direct injection of drugs into a nerve have occurred in the health care system The commonly affected nerves are the median and ulnar of the upper extremity and the sciatic and tibial nerves of the lower extremity.³

The onset of pain is usually immediate in CRPS type II as opposed to CRPS type I, which is often delayed for weeks. Pain may spread proximally and is often described as burning, however other qualities such as tingling, vibrating, and aching have been described in both CRPS type I and type II.^{3, 11}

Clinical signs include temperature changes in the affected area, evidence of other vasomotor (blood flow) changes such as redness, blanching, or a purple-red splotchy pattern of the painful area may be present as well. Other changes include excessive sweating (hyperhydrosis), glossy skin in the affected region and nail bed changes. Motor weakness, may be present although this is not a criterion for diagnosis. Pain must be present to make the diagnosis and may be in the form of mechanical or thermal allodynia or hyperalgesia. Approximately 25% of children with CRPS will not have a temperature differential between the affected and unaffected limb.¹¹

There are no definitive diagnostic tests to diagnose CRPS in children. Immersing the affected area in ice and then mapping temperature changes of the regions of the limb may indicate CRPS but is not specific for the diagnosis. Triple phase bone scans are positive in only 53% of adult patients with CRPS; however, in children, there is increased radionucleotide uptake relative to adults at baseline and is decreased with CRPS type I.¹² The quantitative sudomotor axon reflex test (QSART) examines baseline and evoked sweat production by iontophoresis of carbachol. The quantitative sensory test (QST) examines small fibers transmitting vibration and heat and cold sensation.^7,13,14

Psychological testing is important to establish personality types, traits and possible disorders. Generally in adults, psychological counseling is not indicated in the initial two months of the disorder because the patient expects to get better and is optimistic. At two to six months duration, the patient becomes anxiously concerned that he or she is not getting better. Psychological evaluation may show mild depression and anxiety. At longer than six months duration, sleep disturbance, anxiety and moderately severe depression are often present.¹⁴

Many pediatric patients initially are misdiagnosed. The gravity of the child's pain often is discounted, so referral to a pain specialist often is later than that reported in the adult experience. Most children experience pain for several months before seeing a pain specialist. Consequently, anxiety and mild depression can be seen at the initial presentation. It is the belief of some pediatric pain experts that there is a greater psychological component in pediatric cases of CRPS; however, the literature does not support that belief.¹¹ Given the time course of psychological progression with chronic illness and the late referral of children to specialists, it would appear that the presenting psychological signs and symptoms are not disproportionate in children.

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Treatment Options

Physical therapy remains the cornerstone of care in children with CRPS.¹⁵ The goal of treatment is progressive functional restoration. Treatment focuses on three domains: active movement from gentle range of motion to aerobics; weight bearing via isometrics and increasing to stress loading; and desensitization where the patient is repeatedly stroked with a smooth material such as silk and is progressed to tolerate a rub from a textured material such as terry cloth.

Invasive Procedures

Children are generally more responsive to conservative therapy than adults. Invasive therapy including neuraxial sympathetic ganglion blocks can be performed on children. These nerve blocks involve injecting an anesthetic (numbing) agent close to the nerves. Systemic administration of ketanserin has been used for cases of prolonged duration.¹⁶ Generally, indirect sympathetic blockade is obtained via an epidural block. In-patient hospitalization for pain management and epidural analgesics with opioids, clonidine and/or local anesthetics have been used for severe cases of CRPS. Adrenoreceptor Bier blocks are reserved for cases in which the patient is unable to tolerant of physical therapy despite the use of pain medications.

The use of implantation devices in the growing neuraxial spine of a child is controversial. Tunneled or closed system intraspinal infusions are reserved for more recalcitrant, debilitating cases and neuromodulation or the use of radiofrequency ablation has not been reported in the treatment of CRPS in children.¹⁷ Unlike the adult population where procedures are performed with conscious sedation, the pediatric population generally requires profound unawareness during the procedure. Using the above invasive techniques often requires heavy sedation or general anesthesia in pediatric cases.

Medications

The child's physician may prescribe a variety of medications to control the various aspects of the child's pain. Tricyclic antidepressants have been the cornerstone of care for children. Amitriptyline is the preferred medication if the child's sleep is disturbed; however, desipramine may be required for children who cannot tolerate the side effects of amitriptyline. Serotonin selective reuptake inhibitors (e.g., Zoloft, Paxil, Prozac) have been tried with variable success. Membrane stabilizers, such as the antiepileptics carbamazepine and phenytoin, may be used for tearing and burning pain, respectively.¹⁶ Gabapentin (Neurontin), a GABA analog has been used in conjunction or alone with some promise. Non-steroidal anti-inflammatory drugs, such as ibuprofen (e.g., Advil) and opioids may offer some relief. The NMDA antagonist activity of methadone has been advocated. Steroids are used when all other systemic agents have failed.

Topical agents such as capsaicin are poorly tolerated however, 5% topical lidoderm patches offer some relief. Clonidine transdermal systems have been placed on the site of pain with only anecdotal reports of efficacy. Systemic pre- and post-synaptic adrenoreceptor antagonists such as phenoxybenzamine are currently under investigation.

Other Therapies

Your child's physician may recommend several different therapies that can be used simultaneously. A non-pharmacological therapy that frequently is tried in children is transcutaneous electrical nerve stimulation (TENS). Some researchers report TENS is effective in more than 60% of cases; however, some children will complain of a worsening of the pain with TENS. Children may become tolerant of TENS and decreased efficacy does seem to occur over time in a significant number of cases.¹⁵

Cognitive behavioral techniques help with coping while distraction, relaxation and vivid imagery may temporarily decrease the pain intensity the child feels. Thermal or electromyographic biofeedback is used in a few centers.

The multidisciplinary approach to pain management is vital and should be instituted early in pediatric CRPS cases that are not adequately responsive to physical therapy. Children often need a pain specialist to manage their care. Pediatricians should actively seek out pain specialist consultative and referral services when challenged with patients who present with unremitting or disproportionate pain. Communication between the referring physician and the pain specialist is key. Changes to mediations should be under the direction of the pain specialist. The care plan must be consistent and clear to all caregivers involved in the treatment of the child.

Researchers are continuing to learn about CRPS, and more information is being found to help understand this neuropathic pain syndrome. The syndrome needs to be further researched on the cause of and predilection for the development of CRPS in childhood.

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Conclusions

• Complex regional pain syndrome (CRPS) is a neuropathic disorder that causes changes to the nerves and the central nervous system.
• There are two types of CRPS – CRPS type I (formerly know as reflex sympathetic dystrophy) and CRPS type II (formerly known as causalgia).
• CRPS typically affects the most distal part of the limb such as the toes and foot or fingers and hand.
• Most children with CRPS type I are about 12 years of age, but the syndrome can occur in younger children.
• CRPS type II can occur at any age
• Most children with CRPS present with a history of minor trauma or repetitive strain type injury.² A simple trip or fall can lead to the onset of CRPS. In CRPS type II, there is known nerve injury.
• The onset of pain is usually immediate in CRPS type II as opposed to CRPS type I, which is often delayed for weeks.
• Symptoms of CRPS type I include continuing pain that seems disproportionate to the initial cause, extreme skin sensitivity in the painful area, and other symptoms such as altered skin blood flow indicated by skin discoloration, and edema or swelling caused by fluid retention.
• The most common treatment option for children with CRPS is physical therapy. The goal of physical therapy is return of the child's function.
• Other treatments include medications for pain, transcutaneous electrical nerve stimulation, and in rare cases, invasive procedures.

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References

1. Janig W, Stanton-Hicks M. Reflex sympathetic dystrophy: a reappraisal. In: Janig W, Stanton-Hicks M. editors. Progress in pain research and management, vol 6. Seattle: IASP Press:1996.
2. Dangel T. Chronic pain management in children, Part II: reflex sympathetic dystrophy. Paedtiatr Anaesth. 8(2):105-112, 1998.
3. Racz GB et al. Complex regional pain syndrome. Seminars in Anesthesia, 15(1):70-87, 1996.
4. Bryant PR. The rehabilitation of causalgia (complex regional pain syndrome- type II). Phys med Rehab Clin N Am 13(1):137-157, 2002.
5. Allen G, Galer BS, Schwartz L. Epidemiology of complex regional pain syndrome: a retrospective chart review of 134 patients. Pain. 80:539-544, 1999.
6. Ciccone DS, Bandilla EB, Wu W. Psychological dysfunction in patients with reflex sympathetic dystrophy. Pain. 71:323-333, 1997.
7. Satterthwaite JR. Clinical examination for reflex sympathetic dystrophy and causalgia. Phys Med Rehab. 10(2):217-227, 1996.
8. Raja SN, Davis KD, Campbell JN. The adrenergic pharmacology of sympathetically maintained pain. J Reconstructive Microsurg. 8:63-69, 1992.
9. Raja SN. Sympathetically maintained pain in Slide Atlas of Anesthesia. S.E. Abram volume editor. R.D. Miller series editor. Current Medicine, Inc. Philadelphia. Chap. 6, 1998.
10. Lagas HM. Reflex sympathetic dystrophy. The Pain Clinic. 8(1):29-30, 1995.
11. Wilder RT. RSD in Children and Adolescents in Reflex sympathetic dystrophy. In: . Reflex sympathetic dystrophy: a reappraisal. In: Janig W, Stanton-Hicks M. editors. Progress in pain research and management, vol 6. Seattle: IASP Press:1996. pp 67-78.
12. Harden RN. A clinical approach to complex regional pain syndrome. Clin J Pain, 16(2 Suppl):S26-32, 2000.
13. Birklein F, Riedl B, Claus D, Neundorfer B. Pattern of autonomic dysfunction in time course of complex regional pain syndrome. Clin Auton res, 8(2):79-85, 1998.
14. Stanton-Hicks M. Complex regional pain syndrome (Type I, RSD: Type II, causalgia): Controversies. Clin J Pain. 16:S33-S40, 2000.
15. Wilder RT, Wolohan M, Vieyra MA, et al. Reflex sympathetic dystrophy in children. J Bone Joint Surg. 74:910-19, 1992.
16. Moesker A. Treatment of hyerpathia/ allodinia in CRPS, earlier called RSDS, a metabolic approach. The Pain Clinic 10(4):261-274, 1998.
17. Stanton-Hicks M, Baron R, Boas R, Gordh T, et al. Complex regional pain syndromes: Guidelines for therapy. Clin J Pain.14(2):155-166, 1998.

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Annotated Bibliography

Wilder RT. RSD in Children and Adolescents in Reflex sympathetic dystrophy. In: . Reflex sympathetic dystrophy: a reappraisal. In: Janig W, Stanton-Hicks M. editors. Progress in pain research and management, vol 6. Seattle: IASP Press:1996. pp 67-78.

A concise, well-organized discussion of the current pediatric experience with CRPS. The paper discusses the prevalence of signs and symptoms in children. This review addresses the epidemiological profiles and treatment strategies of one of the largest reviews of pediatric patient groups ever reported.

Stanton-Hicks M, Baron R, Boas R, Gordh T, et al. Complex regional pain syndromes: Guidelines for therapy. Clin J Pain.14(2):155-166, 1998.

This manuscript reviews the pathophysiology and clinical presentation of patients with CRPS. Treatment regimens given by drug class are discussed. A clear and concise review and guide to the treatment of these syndromes.