Correspondence

More on Reflex Sympathetic Dystrophy Syndrome Following Air-Bag Inflation

N Engl J Med 1998; 338:334-335January 29, 1998

Article

To the Editor:

Reflex sympathetic dystrophy is an outdated term that tends to be used to describe pain that persists when the patient does not respond to therapy. The term implies that the sympathetic nervous system is somehow involved in the pain state; this is not always true. The only way to determine the involvement of the sympathetic nervous system in a pain state is to inhibit the sympathetic nerves supplying the area and to see whether the pain is relieved. What Shah and Weinstein describe as reflex sympathetic dystrophy syndrome following air-bag inflation (Aug. 21 issue)1 has recently been termed the complex regional pain syndrome.2-4

Shah and Weinstein state that continuous pain can result from the tonic effects of the sympathetic nervous system on wide-dynamic-range neurons in the spinal cord. This is wrong. Sympathetically mediated pain derives from the altered sensitivities of receptors on the afferent neurons in the periphery.4-6

A.H. Guarino, M.D.
Washington University, St. Louis, MO 63110

6 References

1. 1

   Shah N, Weinstein A. Reflex sympathetic dystrophy syndrome following air-bag inflation. N Engl J Med 1997;337:574-574
   Full Text | Web of Science | Medline

2. 2

   Campbell JN. Complex regional pain syndrome and the sympathetic nervous system. In: Pain 1996 — an updated review. Seattle: International Association for the Study of Pain, 1996:89-96.
   

3. 3

   Stanton-Hicks M, Janig W, Hassenbusch S, Haddox JD, Boas R, Wilson P. Reflex sympathetic dystrophy: changing concepts and taxonomy. Pain 1995;63:127-133
   CrossRef | Web of Science | Medline

4. 4

   Wesselmann U, Raja SN. Reflex sympathetic dystrophy and causalgia. Anesth Clin North Am 1997;15:407-427
   CrossRef

5. 5

   Campbell JN, Raja SN, Selig DK, Belzberg AJ, Meyer RA. Diagnosis and management of sympathetically maintained pain. In: Fields HL, Liebeskind JC, eds. Pharmacological approaches to the treatment of chronic pain: new concepts and critical issues. Progress in pain research and management. Vol. 1. Seattle: International Association for the Study of Pain, 1994:85-100.
   

6. 6

   Davis KD, Treede RD, Raja SN, Meyer RA, Campbell JN. Topical application of clonidine relieves hyperalgesia in patients with sympathetically maintained pain. Pain 1991;47:309-317
   CrossRef | Web of Science | Medline

Author/Editor Response

Dr. Weinstein replies:

To the Editor: I agree that the term “reflex sympathetic dystrophy syndrome” is outmoded and implies a pathophysiology that may not be correct. The classification Guarino prefers is complex regional pain syndrome types I (reflex sympathetic dystrophy syndrome) and II (causalgia) with sympathetically maintained pain or sympathetically independent pain.1 These may be more accurate descriptors; however, they are cumbersome and create distinct subdivisions for clinical entities in which the lines of distinction in diagnosis and treatment are often blurred. Perhaps we would be better served by the approach followed in Europe, where nonspecific nomenclature such as “algodystrophy” or “Sudeck–Leriche syndrome” is used.2

The mechanism by which the sympathetic nervous system may contribute to the maintenance of chronic pain in patients with this condition is uncertain. Hypotheses have included both sensitization of peripheral adrenergic receptors and modulation of central (spinal) pain-signaling neurons by the sympathetic nervous system.3,4 Despite the putative role of the sympathetic nervous system in some patients, the approach to treatment varies more according to medical specialty than according to postulated pathogenesis. It is common practice for rheumatologists to treat severe cases with a course of systemic corticosteroids or calcitonin and to try sympathetic blockade only when patients are unresponsive to these measures.2 Guarino's approach is to determine the effect of sympathetic blockade as an initial step to guide subsequent therapy. Conceivably, both approaches could have reasonable success rates. Only when the pathogenesis of this group of clinical conditions is more clearly delineated are we likely to reach taxonomic and therapeutic agreement.

Arthur Weinstein, M.D.
George Washington University Medical Center, Washington, DC 20037

4 References

1. 1

   Stanton-Hicks M, Janig W, Hassenbusch S, Haddox JD, Boas R, Wilson P. Reflex sympathetic dystrophy: changing concepts and taxonomy. Pain 1995;63:127-133
   CrossRef | Web of Science | Medline

2. 2

   Doury P, Dequeker J. Algodystrophy/reflex sympathetic dystrophy syndrome. In: Klippel JH, Dieppe PA, eds. Rheumatology. 2nd ed. Vol. 2. London: Mosby, 1998:44.1–44.8.
   

3. 3

   Davis KD, Treede RD, Raja SN, Meyer RA, Campbell JN. Topical application of clonidine relieves hyperalgesia in patients with sympathetically maintained pain. Pain 1991;47:309-317
   CrossRef | Web of Science | Medline

4. 4

   Wesselmann U, Raja SN. Reflex sympathetic dystrophy and causalgia. Anesth Clin North Am 1997;15:407-427
   CrossRef

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