Reflex sympathetic dystrophy syndrome

As discussed in the article by Pittman and Belgrade,[1] the term "reflex sympathetic dystrophy" has been used for most of this century to describe complaints of pain associated with subjective motor or sensory symptoms and erratic objective vascular changes in color and temperature of the symptomatic body part often with enigmatic onset and chronic deterioration. Such complaints undoubtedly exist.[2,3] Although the term is descriptive, it implies that the condition is a scientifically established medical entity, with known' and discrete pathophysiology. However, this concept has recently been challenged.

By description, reflex sympathetic dystrophy is a neurologic complex.[4,5] The term has connotations of neurophysiology (reflex), of the autonomic system (sympathetic) and of tissue decay (dystrophy), and yet a noted neurologist remarked that the condition is "neither reflex nor sympathetic nor dystrophy."[6] Until recently, a vast majority of physicians believed that reflex sympathetic dystrophy is a specific disease in which the pain and the "autonomic" dysfunction are determined by the sympathetic system. Criteria have relied on (1) the common presence of local vasomotor imbalance in the absence of primary vascular disease, and (2) the subjective relief of pain in response to sympathetic nerve blocks. Sporadic attempts have been made to explain the sensory phenomena that often accompany the pain and vasomotor disturbance but without success.

In fact, the ubiquitous clinical profile of reflex sympathetic dystrophy amounts to a nonspecific symptom complex. It may be the consequence of various organic or psychiatric disorders of the nervous system or, in some cases, may amount to malingering. In response to this awareness,[2] taxonomists at the International Association for the Study of Pain put the term reflex sympathetic dystrophy to rest and came up with a substitute -- complex regional pain syndrome type I and II.[7] Type H complex regional pain syndrome is caused by demonstrable nerve injury. In contrast, the term type I complex regional pain syndrome is used when the patient reports pain associated with sensory, motor or vasomotor dysfunction, and the physician does not find an objectively testable explanation. Although the concepts of types I and II complex regional pain syndrome relegate the sympathetic system to a low profile, they allow it to be a circumstantial mechanism. Indeed, in theory patients with complex regional pain syndrome may or may not harbor "sympathetically maintained pain," defined as "all pain syndromes that can be relieved by sympathetic blockade."[18]

The concept of reflex sympathetic dystrophy would not have persisted through much of our century were it not for its legitimization by an apparent diagnostic test, namely the sympathetic block.[4] Such "blocks" are regarded as positive if the patient reports subjective improvement. However, when this test is controlled for the placebo effect, it appears to be no more than a placebo effect.[9-12] That is why sympathectomy does not "cure" reflex sympathetic dystrophy. This is something that the father of this procedure acknowledged in the mid-30s. "Quite a considerable number of surgeons, especially in the United States ... do far too many useless sympathetic) ganglionectomies....When there is neither vascular lesion nor lesion of a nerve, it is not at all likely that an operation on the ganglia will achieve any greater success."[13]

The objective change in color and in temperature, complaints of swelling and increased activity of sweat glands can be deceptive. One might ask how a primary psychologic disturbance could be the cause. Yet studies of positron emission tomography scans are beginning to reveal how, through limbic connections, the emotional brain may modify brain processing of somatic functions.[14] Three-phase bone scan has revealed how bone metabolism may be nonspecifically modified by neuropathy or sympathectomy.[15] Disuse by itself affects both cutaneous and bone blood flow. Usefulness of the quantitative sweat autonomic response test in the diagnosis of "reflex sympathetic dystrophy" has been controversial.[16-18]

Many patients with reflex sympathetic dystrophy those who neither have organic neurologic damage nor malinger, harbor a primary psychiatric disorder in the realm of what used to be called "psychosomatic disease," as updated today under one of the somatoform disorders, such as conversion disorder or somatization disorder.[19-23] This condition has also been called pseudoneurologic illness.[23] Many physicians are unaware of the prevalence and the multiple faces of somatization. Yet it is somatoform disorder that physicians should keep m mind when considering the diagnosis of reflex sympathetic dystrophy/ complex regional pain syndrome. Otherwise, they may either perform unnecessary tests or procedures on affected patients or fail to diagnose the true underlying cause of the patient's problem. Until we have more research on this challenging syndrome, it will continue to be difficult to separate fact from fiction in the management of patients with the vague symptoms of reflex sympathetic dystrophy/ complex regional pain syndrome.

REFERENCES

[1.] Pittman DM, Belgrade MI. Complex regional pain syndrome. Am Fam Physician 1997,56:2265-70.

[2.] Ochoa JL. Essence, investigation and management of "neuropathic" pains: hopes from acknowledgement of chaos [Editorial]. Muscle Nerve 1993;16: 997-1008.

[3.] Ochoa J. Issues and opinions of neuropathic pain [Replies to Drs. Day, Teasell, Shapiro and Merskey]. Muscle Nerve 1995;18:45"2.

[4.] Ochoa J, Verdugo R. Reflex sympathetic dystrophy. Definitions and history of the ideas. A critical review of human studies. hi: Low PA, ed. Clinical autonomic disorders. Boston: Little Brown, 1993:473-92.

[5.] Janig W The puzzle of "reflex sympathetic dystrophy": mechanisms, hypotheses, open questions. In: Janig W, Stanton-Hicks M, eds. Reflex sympathetic dystrophy: a reappraisal. Seattle: IASP, 1996:1-24.

[6.] Landau W. Reflex sympathetic dystrophy [Letter]. Mayo Clin Proc 1996;71:524-5.

[7.] Merskey H, Bogduk N, eds. Classification of chronic pain: descriptions of chronic pain syndromes and definition of pain terms. 2d ed. Seattle: IASP, 1994:40-3.

[8.] Treede RD, Raja SN, Davis KD, Meyer RA, Campbell JN. Evidence that peripheral alpha-adrenergic receptors mediate sympathetically maintained pain. In: Bond MR, Charlton JE, Woolf CJ, eds. Proceeding of the VIth World Congress on Pain. Amsterdam, New York: Elsevier Science, 1991:377-82.

[9.] Verdugo RJ, Ochoa J. Sympathetically maintained pain. I. Phentolamine block questions the concept. Neurology 1994;44:1003-10.

[10.] Jadad AR, Carroll D, Glynn CJ, McQuay HJ. Intravenous regional sympathetic blockade for pain relief in reflex sympathetic dystrophy: a systematic review and a randomized, double-blind crossover study. J Pain Sympt Manage 1995;10:13-20.

[11.] Ramamurthy S, Hoffman J. Intravenous regional guanethidine in the treatment of reflex sympathetic dystrophy/causalgia: a randomized double-blind study. Guanethidine Study Group. Anesth Analg 1995;81:718-23.

[12.] Valentin N. Reflex sympathetic dystrophy treated with guanethidine. Time for a change of name and strategy [Editorial]. Acta Anaesthesiol Scand 1996;40:1171-2.

[13.] Leriche R. The surgery of pain [translated and edited by Young Al. Baltimore: Williams Wilkins, 1939.

[14.] Derbyshire SW, Jones AK, Devani P, Friston KJ, Feinmann C, Harris M, et al. Cerebral responses to pain in patients with atypical facial pain measured by positron emission tomography. J Neurol Neurosurg Psychiat 1994;57:1166-72.

[15.] Mailis A, Meindok H, Papagapiou M, Pham D. Alterations of the three-phase bone scan after sympathectomy. Clin J Pain 1994;10:146-55.

[16.] Ochoa JL. Reflex? Sympathetic? Dystrophy? Triple questioned again [Editorial]. Mayo Clin Proc 1995;70:1124-6.

[17.] Chelimsky TC, Low PA, Naessens JM, Wilson PR, Amadio PC, O'Brien PC. Reflex sympathetic dystrophy [Letter]. Mayo Clin Proc 1996;71:524.

[18.] Ochoa J. Reponse to letter on reflex sympathetic dystrophy [Letter]. Mayo Clin Proc 1996:71:524-5.

[19.] Quill TE. Somatization disorder. One of medicine's blind spots. JAMA 1985;254:3075-9.

[20.] Lipowski ZJ. Somatization: the concept and its clinical application. Am J Psychiatry 1988;145:1358-68.

[21.] Ron MA. Somatisation in neurological practice [Editorial]. J Neurol Neurosurg Psychiatry 1994; 57:1161-4.

[22.] Ford CV. Dimensions of somatization and hypochondriasis. Neurol Clin 1995;13:241-53.

[23.] Shorter E. The borderland between neurology and history. Neurol Clin 1995;13:229-39.

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