Frequency, Mortality/Morbidity, and Distribution:

RSD has significant morbidity, so raising awareness of this disease is important. Earlier recognition and appropriate referral is very important, especially in children. Prompt referral can avoid unnecessary investigations and treatments that may worsen the condition.

RSD is reported more commonly in women. In one study, which reviewed of 829 patients, 628 patients were female (76%) and 201 male (24%).

Clinical History:

Pain is reported in more than 90% of patients. Most patients describe worsening of pain or other symptoms after exercising the affected limb.

Vascular abnormalities, often abnormal vasodilation and skin warming in the early phase and vasoconstriction in later stages, are characteristic symptoms of RSD/CRPS I.

Typically, patients with CRPS exhibit a warm and vasodilated affected extremity in the early stages and cold and pale skin in the later stages.

The common physical characteristic features of RSD (CRPS I) are spontaneous pain, hyperalgesia, impairment of motor function, swelling, changes in sweating, and vascular abnormalities in a single extremity. An overt nerve injury is not detectable.

Various sensory symptoms have been observed, including allodynia (mechanical and thermal); hyperalgesia (mechanical and thermal); hyperpathia; hypoesthesia; hypothermesthesia; and proprioception and anesthesia dolorosa (ie, sensibility to touch is absent while severe pain is present in the anesthetic area). On rare occasions, a dissociated sensory pattern may be noted.

Based on the IASP consensus conference, there are 2 types of CRPS, namely CRPS I (RSD) and CRPS II (causalgia). These 2 types are differentiated mainly based upon whether the inciting incident included a definable nerve injury. CRPS I (RSD) - Occurs after initial noxious event other than a nerve injury. CRPS II (causalgia) - Occurs after nerve injury. In most other ways, CRPS I and CRPS II are quite similar. Features common to both CRPS types I and II include the following:

Pain, whether spontaneous or evoked, may include allodynia (painful response to a stimulus that is not usually painful) and/ or hyperalgesia (exaggerated response to a stimulus that is usually only mildly painful). Pain that is disproportionate to the inciting event (eg, years of severe pain after an ankle sprain). Regional pain that is not limited to a single peripheral nerve distribution. Evidence of autonomic dysregulation (eg, edema, alteration in blood flow, hyperhidrosis). Diagnosis is excluded if another condition could account for the degree of pain and dysfunction.

Causes: Various insults that may lead to RSD include the following: Trauma (eg, sprain, dislocations, fractures, surgery, burns, crash injury); Neurologic disorders (eg, stroke, tumor, syringomyelia); Herpes zoster infection; Myocardial infarction; Musculoskeletal disorder (shoulder rotator cuff injury); Malignancy; Spontaneous/idiopathic.

One study reported that, in 65% of cases, RSD followed trauma (mostly a fracture); in 19% of cases, it followed an operation; and in 2% of cases, it followed an inflammatory process. In 4% of cases, onset of symptoms followed various other precipitating factors, such as injection, intravenous infusion, or cerebrovascular accident. In 10% of cases, no precipitant could be identified. CRPS II (causalgia) has been reported after automated laser discectomy and cervical epidural injection.

Evaluation and Diagnosis:

X-ray films may show patchy periarticular demineralization within 3-6 weeks. The extent of osteoporosis is more than expected from disuse alone, and it is a common abnormality revealed on radiographs.

A 3-phase bone scan may be helpful both in revealing findings typical for the diagnosis of RSD and also in excluding other conditions that could cause the patient's symptoms. A false negative bone scan is fairly common. This scan is often considered sensitive and specific, particularly in the early phase (less than 20 weeks) of the syndrome, but a study by Warner reports that the 3-phase bone scan has shown a diagnostic sensitivity of only 44%.

Scintigraphic abnormalities were reported in up to 60% of RSD patients and may be useful in arriving at the diagnosis of RSD and in predicting which patients are likely to respond to systemic steroid therapy. Abnormal increased activity must be diffuse, not focal.

Other tests include measuring skin temperatures and noting vascular changes. The measurement is simple, but important, to record during examination of the patient with RSD. Skin temperature is measured by (1) tactile perception, (2) surface thermistors, and (3) hand-held infrared thermometers.

There are a host of other complex tests that are beyond the scope of this paper. These include: Sudomotor function testing, sweat test, Quantitative sudomotor axon reflex test (QSART), Chemical sweat test, Electrodiagnostic studies, Diagnostic sympathetic ganglion block and other testing modalities.

Rehabilitation Program:

Physical therapy (PT), in association with occupational therapy (OT), plays an important role in functional restoration. The goal is to increase strength and flexibility gradually beginning with gentle gliding exercises. Patients usually are reluctant to participate in PT because of intense pain. A self-directed or therapist-directed PT program is important and should be individualized to each patient's needs and goals.

Patients with CRPS also may have myofascial pain syndrome. Myofascial pain may be treated with modalities and techniques such as massage and myofascial release.

Occupational therapists usually are responsible for introducing and maintaining a stress loading program for patients with CRPS.The stress loading program usually is started as a home exercise program. The patient also can use desensitization techniques (eg, rubbing the skin, massage, tapping, vibration) to reduce sensitivity and pain.

Recreational Therapy: Recreational therapy can help the patient with chronic pain take part in pleasurable activities that help decrease pain.

All treatments should focus primarily on functional restoration. Use of drugs, sympathetic blocks, and psychotherapy helps to achieve good pain control during physical therapy.

Early intervention is important. The key to successful treatment of RSD is recognition of symptoms in stage I or early in stage II. Physicians should be alert for signs and symptoms of RSD. When RSD is suspected, the treating physician should ensure that that the patient receives evaluation by a pain specialist or other clinician experienced in treating this condition.

Surgical Intervention: For the upper extremity, a stellate (cervicothoracic) ganglion block is recommended. Bupivacaine is preferred over lidocaine because of its longer half-life. Not all patients experience pain relief after blocks.

Percutaneous lumbar sympathetic plexus catheter placement usually provides short-term pain relief in most patients and may have some long-term effect.

Bier block (intravenous regional block) has been utilized with some positive results bu the Somatic block, consisting of continuous epidural infusion with different variants of brachial plexus blocks, includes an axillary, supraclavicular, or infraclavicular approach that has been more useful.

Dorsal column stimulators have been used successfully to relieve localized extremity pain. A spinal cord stimulator (SCS) can be an effective treatment for the pain of RSD, including recurrent pain after ablative sympathectomy.

Complications of the Disease:

Chronic edema (occasionally chronic lymphoedema); Chronic relapsing infections and ulcers resistant to treatment; Brown- grey scaly pigmentations of the skin; Recurrent unexplained spontaneous hematomas; Dystonia, tremor, and other movement disorders; Clubbing of fingers or toes and hourglass nails; Depression and other psychiatric disorders.

Medical/Legal Pitfalls & Special Concerns:

RSD is rare in childhood, but it has significant morbidity. Therefore, awareness of this disease is important, so that children with this condition can be recognized earlier and referred for appropriate treatment. As noted earlier, awareness may avoid unnecessary investigations and treatments that may worsen the condition.