Complex regional pain syndrome is an uncommon neurologic condition that can have devastating effects on athletes. It has been recognized since the U.S. Civil War era in adults, but rarely was mentioned in the pediatric populations until the 1970s. It is at least four times more common in females than males and is seen primarily in the Caucasian population (12).
LD is a 10-yr-old female gymnast. Seven weeks prior to presentation, she "landed short" on vault and sustained an injury to her right knee while attending a gymnastics camp. The magnetic resonance imaging (MRI) at that time showed a partial tear of the anterior cruciate ligament. She was treated by her orthopedist with a knee immobilizer for 6 wk. She was noted to have significant pain and disability at the end of 6 wk, so she was referred to physical therapy for "quad strengthening." The evaluating therapist noted an inability to bear weight, skin color changes, and marked hyperalgesia and allodynia. Her parents brought her to us for further evaluation.
Her past medical history is significant for migraine headaches that required extensive evaluation and a brief hospitalization 18 months previously for treatment. The migraines currently are not requiring any treatment. She lives with both parents and is very successful in school and gymnastics.
On physical exam, she is a pleasant, smiling 10-yr-old girl who presented on crutches. She was noted to have marked allodynia on the posterior part of the right leg extending from the gluteus muscle to the ankle. There was some intermittent mottling of the skin of the leg below the knee. She was unable to bear weight and had very poor muscle control of the right leg.
A tentative diagnosis of complex regional pain syndrome was made and she was begun on desensitizing physical therapy. Her symptoms worsened, and she was referred for inpatient therapy with an indwelling epidural catheter 4 wk after initial presentation. She did improve, but regressed quickly after discharge. She became wheelchair-bound and showed total neglect of the right leg. Trials of gabapentin and baclofen were of no benefit.
She continued with physical therapy 2-4 h·d−1, 5 d·wk−1 for 8 wk. She underwent cognitive behavioral therapy with a sport psychologist and slowly progressed back to full function. She returned to gymnastics and has returned to competition at her normal level of functioning.
Complex regional pain syndrome (CRPS) was first described in 1872 in U.S. Civil War union veterans who developed burning pain after partial traumatic peripheral nerve injury (15). In 1996, the International Association for the Study of Pain (IASP) published diagnostic criteria to help standardize the diagnosis. These criteria were further defined by the Budapest consensus conference of 2004 (2). The Budapest conference defined CRPS as a condition characterized by a continuing (spontaneous and/or evoked) regional pain that is seemingly disproportionate in time or degree to the usual course of any known trauma or other lesion. The pain is regional (not in a specific nerve territory or dermatome) and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic findings. The syndrome shows variable progression over time. It is broken down into CRPS I (without obvious nerve damage) and CRPS II (with obvious nerve damage). The Table shows the clinical diagnostic criteria for CRPS. CRPS also may be subdivided into sympathetically maintained pain (SMP) and sympathetically independent pain (SIP). SMP is defined by pain that responds dramatically to epidural, intrathecal, or lumbar plexus blocks or peripheral nerve blocks (13). SIP implies a more central process and has a poorer prognosis.
In the past, CRPS was divided into three phases: the acute phase, lasting up to 3 months, the subacute or dystrophic phase lasting from 3 months to 12 months, and the chronic phase, which encompasses symptoms lasting longer than 12 months. A recent article has called this classification into question (1), and the International Association for the Study of Pain (IASP) does not use this distinction in diagnosis. In one article, the average time from onset of symptoms to diagnosis was 14 wk (5). The physician should consider the diagnosis whenever a patient presents with pain out of proportion to physical findings in an extremity, especially after there has been a period of immobilization. The history should focus on the development, time course, and distribution of the pain. Note any swelling, temperature, and motor changes in the involved area. There are no diagnostic tests required for the diagnosis, but often plain radiographs, bone scan, and MRI should be obtained to look for other causes of the symptoms, especially in children. In the subacute phase, bone scan will show increased tracer uptake in the distal joints of the involved extremity (15). Plain radiographs may show disuse osteoporosis in patients with chronic CRPS.
Treatment of CRPS requires a multidisciplinary approach. No single therapy has been shown to be effective for the majority of patients. Most recent trials report use of physical therapy along with one or more other modalities, including cognitive behavioral therapy, pharmacotherapy, and interventional techniques (4,5,12). Very few randomized controlled trials have been performed to evaluate the efficacy of any single or combination of therapies. Treatment should be individualized and may encompass some or all of the interventions mentioned here.
The goal of physical therapy is first to accomplish desensitization, reestablish range of motion, and then return to functional activity. Massage, whirlpool, pool therapy with progressive weight bearing, and fluidotherapy are used to desensitize and restore the ability to bear weight. A review of published studies did show that graded motor imagery has strong evidence of effectiveness in adults (4). In the adolescent athlete, play therapy can be used to improve functional ability while providing distraction from pain. Frequent, aggressive therapy up to 5 d·wk−1 has been advocated by many (8,12). Some protocols recommend pain-relieving medications prior to therapy, while others do not (5,11,13). It is important that during therapy the patient does not let discomfort limit what he or she can accomplish.
COGNITIVE BEHAVIORAL THERAPY
While it is now accepted that this is not a psychological problem, the use of cognitive behavioral therapy is a mainstay of the multidisciplinary approach to managing CRPS (2). Therapy focused on guided imagery, coping mechanisms, and biofeedback have all been used. Combining relaxation exercises and cognitive interventions designed to increase perceived control over pain as part of a physical therapy program improved pain relief over standard physical therapy in one study (7). No randomized controlled trials have been performed to evaluate the efficacy of psychological intervention, but a large number of case reports and expert opinion support this intervention (2). Psychosocial factors are thought to play a greater role in children (12).
Multiple medications have been used in the treatment of CRPS with varying success (2). Very few double-blind studies have been described. Nonsteroidal antiinflammatory medications have not shown benefit in the treatment of CRPS but commonly are used to treat mild to moderate pain. Medications with some evidence for efficacy include the tricyclic antidepressants, gabapentin, carbamazepine, opiods, clonidine, nifedipine, calcitonin, bisphosphonates, alpha adrenergic antagonists, the 5% lidocaine patch, and topical capsaicin (5). Oral glucocorticoids given early in the disease process, when inflammation is felt to play a more important role, have shown benefit over placebo (2). One randomized controlled trial of gabapentin in the treatment of CRPS I showed no pain relief over placebo but an improvement in sensory deficits (14). Of note, the largest published series of pediatric patients with CRPS showed a 92% success rate without the use of medications (11).
Interventions that interrupt the sympathetic nervous system historically were used to diagnose and treat CRPS. As our understanding of the disease has progressed, this procedure has been called into question (2). Many patients with CRPS have sympathetically independent pain and will not respond to sympathetic blockade. If the block is performed and is successful, then the patient is believed to have sympathetically mediated pain and is a candidate for a short series of blocks in conjunction with physical therapy (2). Intravenous regional anesthetic blocks also have been used for years, but a recent meta-analysis showed no proven effect for this therapy (10).
Continuous lumbar epidural analgesia is used for pain control during intense physical therapy and has shown some benefit (3). Sympathetic ablation by phenol injection, surgery, or radiofrequency ablation is used to treat sympathetically mediated pain, but there are no high-level evidence studies evaluating the efficacy of these interventions (2).
Finally, spinal cord stimulation and transcutaneous electrical nerve stimulation (TENS) have been used to treat CRPS (2). The TENS unit can be used early, but the spinal cord stimulator is reserved for refractory cases. In adults, spinal cord stimulators have shown good results early on, but the pain-relieving effects diminish over time, to show no statistically significant benefit at 5 yr (6). A small case series report showed excellent results from spinal cord stimulators in adolescent girls for 1-8 yr post-procedure (9).
The prognosis for patients with CRPS is quite variable and unpredictable. Case reports and series show excellent results from exercise-based therapy in the pediatric and adolescent patient (11). The recurrence rate in children is quite high, however. One study showed a 36% recurrence in CRPS symptoms during a 12-month follow-up period after initial success (4). It is unknown whether repeat treatment leads to better long-term disease-free intervals.
Complex regional pain syndrome should be included in the differential diagnosis whenever an athlete presents with pain greatly in excess of what would be expected after an injury. It is more common in females and more common in the lower extremity in the pediatric population. The syndrome involves changes in both the peripheral and central nervous system. Imaging and laboratory tests are not needed to make the diagnosis but may be necessary to rule out other pathology. All treatment regimens should include physical therapy to include desensitization, passive and active range of motion, isometric exercises, and proprioceptive training. Medications, cognitive behavioral therapy, and interventional procedures to induce a regional sympathectomy are all used in selected patients. The overall prognosis is good, but recurrence is common.
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