Diagnosing Reflexive Sympathetic Dystrophy: Have Scans Been Panned?

December 31, 2006

I see patients with reflex sympathetic dystrophy (RSD) after industrial accidentsand for independent medical examinations.

I see patients with reflex sympathetic dystrophy (RSD) after industrial accidentsand for independent medical examinations. Often, little objective evidence ofinjury is present, but the patient reports a great deal of pain and disability. What isthe role of bone scanning in diagnosing RSD and in determining the prognosis foraffected patients? How well do the findings correlate with the patient's use of theextremity involved?
-- Sarita Salzberg, MD
   Columbus, Ohio

RSD is a controversial topic. Some experts do not consider it a disease atall.1 Others believe RSD arises from psychological phenomena,2 whilestill others consider it a disease of unknown origin.3Consequently, use of the triple-phase bone scan to diagnose RSD isalso controversial. According to some authorities, a bone scan is necessaryto properly diagnose RSD.4 For a scan to be considered positive for RSD,the first phase should show a diminished flow to the involved extremity andthe third phase, periarticular uptake. In patients with a positive scan, plain radiographswould show periarticular osteoporosis (rather than generalizedosteoporosis), as seen in disuse of a limb. However, it has been reported thatuse of a tourniquet on a limb can produce bone scan findings identical tothose considered diagnostic of RSD.5 Other authorities dispute the usefulnessof bone scanning in the diagnosis of RSD.6My own experience is that patients with the classic presentation of RSD(burning pain, allodynia, hyperpathia, hyperhidrosis, discoloration, edema ofskin and subcutaneous tissue, and cold skin) also demonstrate the bone scanfindings described above. In such patients, the bone scan indicates lack of useof the limb as well. Absence of typical bone scan findings strongly suggeststhat the diagnosis of RSD is not appropriate and that the patient is using thelimb in a normal manner.
-- Ronald P. Pawl, MD
   Associate Professor of Neurosurgery
   University of Illinois
   Lake Forest

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