CRPS (Complex Regional Pain Syndrome)

Complex Regional Pain Syndrome.

Lorraine M. Taylor, MSN, CFNP

Complex regional pain syndrome (CRPS) has been reported and studied in adults for many years. It is a less acknowledged disorder in children, probably due to underdiagnosis. The presentation and response to treatment of CRPS differs in the adolescent as compared with the adult form. In both the adolescent and adult with CRPS, the single best prognostic indicator is early recognition and treatment. The purpose of this paper is to highlight these differences and educate healthcare providers in an attempt to positively affect the outcome of this potentially devastating disease. An illustrative case is reported.



CRPS, formerly known as reflex sympathetic dystrophy (RSD), refers to a debilitating neuropathic pain disorder. Continuous severe burning pain and vasomotor instability that has been attributed to autonomic nervous system dysfunction are the primary manifestations of the syndrome. CRPS usually affects an extremity, but can affect any part of the body.[1] It has been recognized and reported in adults since the days of the American Civil War, but it was not until the 1970s that it was acknowledged as an entity in children.[2,3] Currently, CRPS is defined as a syndrome because it may include more than 1 disease entity.[4] The diagnostic criteria and treatment modalities of CRPS have long been a matter of controversy and debate due to the poorly understood pathophysiology. It has, however, been recognized that this syndrome differs significantly in adolescents in its presentation and its response to treatment as compared with adults.[3,5-12] Although uncommon in the pediatric population, CRPS is not rare. Left untreated, the symptoms can become chronic, spread to other parts of the body, and persist for years.The earlier it is recognized and treated, the better the prognosis.[1]



The purpose of this paper is to highlight some known differences between the adult and childhood forms of CRPS in an attempt to educate healthcare providers who often see these cases early in the course of the disease. Nurse practitioners and other advanced practice nurses are in an ideal position to affect the outcome of this disease by early diagnosis and proper treatment. CRPS may even be prevented by early recognition of key signs and symptoms and appropriate early intervention.

Pain is essential to the function and protection of our health. It warns us to withdraw a hand from a hot stove or alerts us when we are ill. In CRPS, the pain signals are an aberrant alteration of this vital sign. In this condition, the pain signal to the brain is exaggerated and inappropriate. A way to explain the process in concrete terms might be to think of pronouncing a newly learned word incorrectly. Each time you draw on your memory, when reading the word in the future, you remember the incorrect pronunciation. In other words, your brain remembers the error. This happens with the pain signals in CRPS. Further exaggeration of this incorrect signal is caused by disuse of the limb. Inactivity serves to complicate the pain stimulus by reducing the proprioceptive input and its inhibitory effect of pain at the level of the spinal cord, resulting in unopposed hyperactivity of the sympathetic nervous system, causing further vasoconstriction, spasticity, and inactivity. This is known as Livingston's vicious circle.[13] Why and exactly how all this happens and whether dysfunction of the sympathetic nervous system is the primary cause of this disorder have been a major source of controversy in the medical literature.

History

CRPS can present with a wide range of symptoms, but the hallmark is pain out of proportion to the inciting event. It usually occurs in the hands or feet, which are rich in nerve innervation, but can present anywhere on the body. The initial injury may be a sprain, dislocation, fracture, laceration, stroke, myocardial infarction, surgery, or it may even follow an intramuscular injection.[1] Pain is generally described as constant, burning, aching, and/or throbbing. Different types of pain are described, including spontaneous, stimulus evoked, and spontaneous paroxysms of pain.[4] Symptoms can consist of allodynia (pain evoked by a mechanical or thermal stimulus that usually does not cause pain, such as light touch), hyperalgesia (exaggerated response to a normally nonpainful stimulus), and hyperpathia (abnormal painful reaction to a stimulus). The pain can start within hours to weeks of the inciting event and lasts well beyond the expected time to recover.[15] It can be exacerbated by immobilization, as with a splint or cast.[5] The pain does not necessarily remain in the area of a specific dermatome or peripheral nerve. A classic feature of CRPS is its tendency to spread proximally to involve the entire extremity or ipsilateral quadrant of the body, the contralateral extremity, or even to other body parts. There are rare cases, usually those that are not diagnosed or treated until very late in the course of the disease, that can become systemic or involve the entire body.[5,13,16]

The history of the adolescent who presents with CRPS often differs from the adult in many respects. First, adolescents are much less likely to have a major trauma preceding the condition. Only about half clearly recall the inciting event or time that the symptoms started, whereas most adults do recall the inciting event and first symptoms. CRPS is more likely to affect girls (80%) with a mean age of 13 years old. It is considered rare in children younger than age 7 years. In the adolescent with CRPS, the lower limb is much more likely to be involved, while upper extremity involvement is more common in adults.[5]

Physical Findings

Adult patients may present with overt autonomic signs involving skin color and temperature changes in the affected limb. The color can be purple, blue, gray, red, or mottled. The temperature can be hot or cold. Edema is usually present at some time in the course of the disease. Swelling can progress to the point that the overlying skin may be tight, shiny, and may even desquamate. Muscle spasm, atrophy, weakness, and limited mobility can occur. Hyperhidrosis (increased perspiration) has also been seen in the affected extremity. Accelerated hair and nail growth may be found initially but with time may become sparse and brittle. Other patients may present without overt autonomic signs, but may have identical history and symptoms. These patients tend to be harder to diagnose and have a poorer prognosis, possibly related to delayed treatment. Their exams may appear mostly normal apart from the characteristic of consistent, disproportional pain.[5,16]

The signs and symptoms of CRPS vary widely in the adolescent; however, clinical signs tend to be more impressive than in adults -- adult presentation is more subtle (Figure 1).[13] When there are overt autonomic signs in adolescents, they more often present with a cold extremity, as opposed to the initial presentation of heat and redness in the adult. Hyperhidrosis is less often present in adolescents. Some researchers have suggested that adolescents are less likely to develop trophic changes, yet some studies show that these changes can be seen in children.[3,7,8] Adolescents without overt autonomic signs are more likely to have multiple sites of pain

Psychosocial Factors Associated With CRPS

Psychosocial factors associated with CRPS have long been a cause of disagreement. The fact that these patients are often labeled as having a psychiatric illness rather than a physiologic one is quite often a great source of suffering. There have been several extensive literature reviews that have shown that psychological symptoms related to CRPS are a result and not a cause of the disorder.[4,8] Because pain is subjective, it lends itself to allegation that the origin is not organic. This is especially true when overt signs of CRPS are not present. Depression and anxiety are common results of chronic pain and must be addressed. In addition, the healthcare provider's attitude toward the patient can also be a source of distress. It is of utmost importance that the patient's pain is accepted, so as not to intensify the psychological sequelae of chronic pain.



Some studies report that psychosocial factors or certain personality traits are frequently found in adolescents with CRPS, suggesting that it may be a stress-related disorder.[10] However, adolescence is a time of great physical and psychological growth. It is also often a time of psychological turbulence, even without the additional issue of illness. Thus, it is possible that the psychosocial factors identified are inherent to the developmental stage of this population.

Cognitive, emotional, and social stages must be evaluated and dealt with individually. Factors that affect the adolescent's ability to deal with chronic pain include real and imagined losses and fears, differences in pain thresholds, differences in coping strategies, and dependency levels. Children in pain respond very differently to pain than adults.[5,17,18] Children and adolescents will often respond to pain within the context of the family. It has also been documented that many children with chronic pain may have incongruent affects.[5] In other words, they may say that their pain is 10/10 yet still have an expressionless face. All of these issues are important to understand when dealing with the child or adolescent with chronic pain. Working with these children poses great challenges to help them learn positive coping strategies and avoid maladaptive behaviors.

DiagnosisCRPS is considered a clinical diagnosis. Specific defining criteria for the disorder have been established and, therefore, it is not a diagnosis of exclusion, as outlined earlier in Table 1. CRPS is a symptom complex, and not all patients will present with all of the signs and symptoms of the syndrome. Patients may present with only 1 or 2 signs and symptoms, which makes diagnosis more difficult.[15] Because of the complexity of the disorder, the average time to diagnose CRPS has been between 9 and 12 months after the initial presentation.[2,8,12] There are 3 proposed stages of CRPS: acute inflammatory, dystrophy, and atrophy. Progression through these stages is variable and signs and symptoms may change from one stage to another.[6,13,19] There are no tests or procedures that conclusively confirm or rule out the presence of CRPS. Tests should only be done to rule out other potential causes with similar presentations. The differential diagnoses that need to be considered are contained in Table 2.[15]

Diagnostic tests such as, radiographs, 3-phase bone scan, magnetic resonance imaging (MRI), thermography, and electromyograms have been used in an attempt to diagnose CRPS and may be helpful when clinical signs are not present.[1,6,20] However, these are not usually necessary and it is important to keep in mind that negative tests do not exclude the presence of CRPS. Sympathetic nerve blocks are often used as a diagnostic test as well as treatment of the disorder, by temporarily blocking the sympathetic activity to the affected extremity.[1] Some practitioners believe that a positive response, with complete or partial remission of signs and symptoms, is felt to be diagnostic of CRPS. Other practitioners believe that a placebo effect may play a role in some cases. Unfortunately, many practitioners still feel that a negative response rules out CRPS. Yet studies of sympathetic nerve blocks show a success rate that varies between 0% and 95%.[21,22] In addition, unnecessary testing that yields abnormal results can be a cause of distraction, further complicating an already difficult diagnosis.[5]

Radiographs may show generalized osteoporosis after prolonged disuse in adolescents, but spotty osteoporosis, the late feature seen in adults, has not been reported in adolescents.[7] Bone scans sometimes show a characteristic spotty increased uptake in adults. A decreased uptake in the affected limb, or a decrease in blood flow on the blood pool phase of the bone scan has been reported in adolescents with CRPS.

Treatment

Due to poorly understood pathophysiology, treatment for CRPS has relied on several unproven therapies. Many are supported only by favorable outcomes in many diverse cases. There is not a single therapy or management program that will work for every case. What has been concluded by most specialists is that the earlier treatment is instituted, the better the outcome. The main goals of therapy are pain relief and restoration of function. A multidisciplinary approach has been found to be the most successful.[7,8] Medications commonly used to treat CRPS are noted in Table 3. Additional therapies include transcutaneous electrical nerve stimulation (TENS), physical and occupational therapy, cognitive-behavioral therapy, psychotherapy, spinal cord stimulation, sympathetic nerve block, and sympathectomy (not recommended because of the high rate of pain recurrence of symptoms after 6-12 months).[15]

Effective treatments of adolescents with CRPS have shown to be much different than those successful in adults. In adults, aggressive pharmacologic intervention has been the standard. In adolescents and children, it appears that the more conservative approach is often adequate. Physical therapy tends to be the primary mode of treatment in children, with the vast majority recovering and managing relapses with this treatment modality. It is thought that exercise works by inhibiting the sympathetic stimulation, increasing circulation, and releasing endorphins.[6,13] Psychological treatment including biofeedback, relaxation methods, self-hypnosis, and distraction techniques have been found to be very beneficial and even a necessary part of management for this age group. Individual and family psychotherapy can be helpful in individual cases.[5,7,10,23] TENS has also been reported to be more effective in children than in adults.[7,23] The use of corticosteroids in children has shown very little benefit and, because of the potential side effects, should be avoided in this population.[7] Sympathetic blocks should be reserved for those refractive to conservative therapies. Some studies report that they are rarely effective in children, while others have found that they can be very successful. An epidural block to break the cycle of pain and allow for initiation of physiotherapy is sometimes required in severe cases.[3,7]

The most successful treatment of CRPS in adolescents and children has been intensive physical and occupational therapy combined with cognitive-behavioral modalities.[5-8,11,23] Providing therapy for 1 to 2 hours a day is not effective. Aggressive, multidisciplinary therapy, for 5 to 6 hours a day, is often required. First, reassure the patient that the pain is real, but that use of the limb is not harmful and is in fact beneficial. There is generally an increase in pain at the initiation of the program but this is offset by distraction and other techniques to help the patient deal with the discomfort.[6]

Techniques such as playing board games on a tall table while encouraging the patient to stand on the affected extremity is an example of a successful distraction method. Races and competition games tend to divert attention away from pain and motivate patients to become more active in their own care. Desensitization can be very effective. Contrast baths, consisting of repeatedly placing the affected limb in lukewarm water for 2 to 3 minutes and then in cold water for 2 to 3 minutes, appear to affect the autonomic dysfunction and calm the allodynia. Lotion or towel rubs to the affected limb are also helpful.

Timidness on the part of the therapist must be avoided because it perpetuates fear that the action is harmful. A critical component of the therapy for this age group is that the pain needs to be acknowledged but ignored. Pool and hydrotherapy are also modalities that distract and promote nonweight-bearing movement of the extremity. Weight-bearing, aerobic, and strengthening exercises are increased as tolerated. This type of program has met with very rewarding results. One report indicated that 90% to 95% of their adolescent patients have regained full function within 1 to 2 weeks of their program. About 15% of these children have had relapses, but have been successfully retreated. At 5 years, they found 90% of their patients were fully functioning and pain free.

Case Report

A 14-year-old female dropped school textbooks on the dorsum of her left foot.(not me) The next morning, she complained of burning pain on the plantar aspect. She continued weight bearing until 7 days later, when her left foot became edematous, erythematous, and developed a distinctly colder skin temperature compared with the contralateral limb. She complained of constant burning pain over the site of injury. She presented to her family physician with an edematous, purple, cold left foot, decreased range of motion, and an inability to bear weight without severe pain. Pulses were 2+ and equal bilaterally, with brisk capillary refill. An x-ray was negative and a 3-phase bone scan was normal except for decreased blood flow of the affected foot. The patient was then referred to a neurologist who diagnosed CRPS and started her on carbamazepine and verapamil.

The patient's past medical history was significant for type-1 diabetes of 7 years duration. She had been using an insulin pump for 4 years and her diabetes was well controlled. At age 11 years, she had a 1-week episode of bilateral hand erythema, swelling, and burning pain that was exacerbated by cold. The symptoms spontaneously resolved and never recurred. Since the episode coincided with menarche, it was presumed to have been Raynaud's phenomenon. All rheumatologic blood work at that time was negative. There was no family history of muscle or nerve disease. Social history was negative for smoking or recreational drug use. She had no emotional or psychiatric symptoms or disorders and appeared to be well adjusted to her type-1 diabetes.

During the week following medication induction, the patient's pain increased. Pain was reported at 8-9 out of a scale of 10 the majority of the time. She described excruciating pain with any elevation of the limb, the slightest touch of a sheet, even a breeze of air on her skin. The edema and burning had now spread to encompass her entire foot and ankle. Lidocaine transdermal 5% patches provided some relief, and physical therapy for desensitization was initiated for 1 hour 3 times a week, but was unsuccessful due to the severity of the pain.

The patient was then referred to a pain management team. The diagnosis of CRPS was questioned due to the aggressiveness of the signs and symptoms when compared with cases that this practitioner had seen in the past. Over the next week, 2 sympathetic nerve blocks were attempted but were unsuccessful in relieving her symptoms. The diagnosis of CRPS was again uncertain. A Doppler study was done but showed no sign of vascular disease. The patient was then released from care of the pain management team under the assumption that the diagnosis was diabetic neuropathy.

Hydrotherapy was tried with a home whirlpool and provided some comfort. A short course of steroids was given without significant benefit and a physiatrist was consulted. Nortriptyline was initiated and the carbamazepine was switched to gabapentin. In spite of treatment, the pain was reported as overwhelming and the patient was unable to take her foot out of warm water for several hours. She was hospitalized and an epidural block was placed to break the cycle of pain. The epidural was effective in decreasing the pain to 0-2/10. The patient was able to elevate her foot and the skin temperature normalized. After 4 days of continuous epidural, the patient was discharged with pain at 4-5/10 and crutches. Within 4 days of her release she became pain free and was able to bear weight. This persisted for 2 days and then symptoms returned.

The patient was readmitted and a second epidural placed. Although 4 epidurals were attempted, the left leg never became anesthetized. The pain continued to spread up the limb, involving the entire left leg to the groin. There was measurable edema and a dramatic decreased skin temperature up the thigh to the groin (Figure 1). In addition, the patient was now unable to stand on the right leg due to pain as a result of the many attempted epidurals. The diagnosis was again in doubt. An MRI was done to look for possible spinal pathology. There was none found. The patient was now confined to a wheelchair and needed assistance to be transferred.

The patient's pain continued to be unrelenting and narcotic painkillers were initiated, but were unsuccessful in alleviating the pain. The gabapentin was increased to 3600 mg per day. The patient became depressed and afraid of sleep. This was secondary to an increase in night pain, development of painful myoclonic movements of the affected extremity while sleeping, and nightmares (Figure 2). The patient's parents, out of frustration, then took the patient to a pediatric tertiary care center, Boston's Children's Hospital, for further evaluation.

PAIN

Burning coldness
crushing,
Numb and hot
Help me someone,
Make it stop!
It started out so innocently
When three books fell upon me
My foot began with a twinge
Then relentlessly,
Crept up my limb
It became unbearable
Moments passed like years
Looking for a miracle
A never-ending nightmare
Guillotines, power saws
Alligators and lion's jaws
Nightmares of horror
Terrified to close my eyes
Fearing more awaits inside
Branded by the endless pain
Am I going to go insane?
You don't know just how I feel
Does that mean it isn't real?
is my world just not true?
Don't I see and feel -- like you?
Please don't stop trying
I can't help my crying
I feel so maimed
Help me, Help me
I'm in pain!

Figure 2. Poem written by Brittney, 14-year-old female with CRPS. Reprinted with permission from the author.


The diagnosis of adolescent CRPS was confirmed. The patient was then transferred and hospitalized in a rehabilitation facility for children, A.I. duPont's Hospital for Children, in Wilmington, Delaware, where she underwent desensitization therapy, distraction, self-hypnosis, and 5 to 6 hours a day of intensive physical and occupational therapy for 1 month. Within 3 days of entering the program, she was walking. By the end of the first week, musculoskeletal pain due to disuse of the limb over the 2 and a half-month course of illness replaced the neuropathic pain. The patient was weaned from all medication and, on follow up, remains medication free. Symptoms have recurred periodically since discharge, but have been aborted quickly with the use of the treatment modalities learned from the rehab program.

Discussion

This case demonstrates how adolescents are not "little adults" with CRPS. They present and respond differently from adults with a similar disorder. Understanding this will avoid unneeded tests, treatments, and suffering. This case fortunately had a positive outcome. However, the medical personnel involved initially did not have the information that adolescents with this disorder respond differently from adults to treatment. Adults with CRPS tend to have a poorer prognosis, with a course that is typically chronic. Growth hormones appear to have a healing effect on the nerves and therefore the outcome tends to be less chronic in the younger population.[6] However, in both adults and children, the pain of CRPS is reported to become irreversible if not treated adequately and early in the course of the disease. The longer the patient suffers, the more complex the pain becomes. After several months, in addition to neuropathic pain, there is also the pain of contractures and atrophy of disuse.



Summary



When treating limb trauma, there are preventive measures that can help avoid the development of CRPS. These consist of avoiding unnecessary surgeries on nerve-rich limbs, avoiding immobilization, initiating early remobilization for minor injuries, and early, effective analgesia.[8] CRPS is not a self-limiting disease. Recognition and treatment of this disorder within the first 3 to 6 months of the onset is the single best prognostic indicator. CRPS should always be considered when limb pain is out of proportion to the inciting event, or lasts beyond the expected time for recovery. Treatment response for CRPS varies widely; however, in adolescents, the most proven effective therapy is intensive physical, occupational, and cognitive-behavioral therapy. An attitude of acceptance that the patient is experiencing real pain is an integral part of successful management. Further studies need to be done in the area of CRPS, especially in adolescents and children, to help identify effective ways to diagnose and treat this often devastating disorder.