Carole W. Agin History and Clinical Presentation
A 50-year-old woman was undergoing magnetic resonance imaging (MRI) with contrast. Intravenous access was started in her right antecubital fossa. As the infusion of gadolinium was started, the patient reported a burning pain in her arm from the antecubital fossa to her fingers. Her forearm and hand swelled. As the swelling increased, she reported numbness and cyanosis. Over the next few days the swelling resolved. Slowly sensation returned to her arm; however, the patient reported a constant burning pain. The patient also noted changes in the color of her hand and pain with movement of her wrist, elbow and shoulder.
There are no radiologic findings that are pathognomonic for complex regional pain syndrome (CRPS) type 1, reflex sympathetic dystrophy (RSD). Radiologic findings are often nonspecific, and many findings are a result of prolonged disuse, which is attributable to the pain associated with the syndrome. However, imaging studies can support a diagnosis of CRPS (RSD).
Fine detail radiography may help to suggest the presence of CRPS. Early radiologic changes seen with sympathetic hyperdysfunction include patchy demineralization of the epiphyses and short bones of the hands and feet. Periarticular osteoporosis in long bones and diffuse osteoporosis in small bones may be seen on plain radiographs. Sub-periosteal resorption, striation, and tunneling of the cortex may occur. Comparison with the unaffected limb is always required. Unfortunately, these findings may be seen whenever there is disuse of a limb. As CRPS advances, patchy osteopenia may be seen.
Triple-phase scintigraphy has also been used to help diagnosis CRPS (RSD). Three-phase bone scanning measures the uptake of a radionucleotide tracer at three different times: arterial phase, measured seconds after the injection of tracer; soft tissue phase, measured after several minutes have passed; and mineral phase, measured hours after the tracer is given. The triple-phase bone scan pattern most consistently seen in a patient with CRPS (RSD) is that of increased flow to the involved extremity and delayed static images that show diffusely increased uptake activity throughout the involved extremity, usually in a periarticular distribution.
MRI studies may show skin thickening and tissue edema. Nuclear bone density measurements have been used to follow the progression of the syndrome.
Peripheral neuropathy disease
Infectious disease Vascular disease Connective tissue disorder Reflex sympathetic dystrophy
CRPS (RSD) is often a diagnosis of exclusion. Other causes of similar pain complaints include peripheral neuropathies, which may also present with neuropathic pain. Traumatic injuries to nerves may present with dysesthesia and hyperpathia, but without the sympathetic component. Inflammatory and infectious causes for pain needed to be ruled out when autonomic dysfunction is the primary presenting symptom. Examples of this would include tenosynovitis and bursitis. Vasculitis and vascular disorders can also manifest with similar findings. In many instances vascular diseases present with bilateral symptoms. Raynaud's disease produces vasospasm that will lead to findings of pallor, cold skin, and potentially cyanosis. Connective tissue disorders also have to be ruled out. Myofascial pain may also present with a nondermatologic distribution of pain. These patients may report burning pain as a symptom and have tender trigger points in the affected muscles. Malingering and psychiatric disorders must also be ruled out as a cause of the patient's unremitting pain, which presents out of proportion to the inciting event.
Complex Regional Pain Syndrome, Type 1 (Reflex Sympathetic Dystrophy)
The Committee on Taxonomy of the International Association for the Study of Pain (IASP) recently renamed reflex sympathetic dystrophy as complex regional pain syndrome type 1. This new taxonomy was promulgated in an attempt to establish uniform diagnostic criteria. This will aid in the development of treatment protocols for the syndrome. Previously many symptom constellations were included within the category of RSD, making treatment pathways and outcome studies difficult. A study done to evaluate the validity of the IASP's CRPS diagnostic criteria to distinguish between CRPS and other neuropathies showed that the new classification did assist in improved accuracy of diagnosis.
To meet criteria for CRPS type 1 a patient must present with regional pain outside of the distribution of a single peripheral nerve and out of proportion to the inciting event. CRPS has been reported to develop after compression/crush injuries, lacerations, fractures, sprains, burns, or surgery. Allodynia and hyperalgesia are typically present. Abnormalities in skin blood flow (causing changes in skin temperature and color), abnormal sudomotor activity, and edema are also present. Dystonia and weakness, although not necessary for the diagnosis, may also be present. Trophic changes and personality changes may develop as the disease progresses.
CRPS type 2 has all of the same signs and symptoms; however, it follows injury of a major peripheral nerve.
As the pathophysiology of CRPS type 1 (RSD) is not well understood, multiple treatment protocols have been described. The consensus is that these patients do best with a multidisciplinary treatment plan (Table 19-1). This includes regional blockade (Fig. 19-1), physical therapy, pharmacologic therapy, and psychological
Interventional Technique Physical Modalities Psychological Interventions
Antidepressants, TCAs, SSRIs
Membrane stabilizers Anticonvulsants Local anesthesia Antiarrhythmic
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