Reflex sympathetic dystrophy: facts and hypotheses.
|Complex Regional Pain Syndrome Type I (CRPS-I), formerly known as reflex
sympathetic dystrophy, has long been recognized clinically. The purpose of this review was to outline the etiology, signs,
and symptoms of CRPS, and examine the diagnostic tests and therapeutic options currently available. CRPS-I is associated with
a wide variety of precipitating events, including injury to or disease of neural tissue, either centrally or peripherally.
Usually, CRPS-II, formerly referred to as causalgia, is easily diagnosed because the precipitating event is an obvious trauma
to a major nerve trunk, to tissues in close proximity to a major nerve trunk, or to regions rich in nerve endings. CRPS-II
can also be caused by seemingly minor trauma. It has been reported that CRPS-I occurs most frequently in women > 50 y/o.
Speculation exists on whether psychological factors may predispose particular individuals to the development of CRPS-I.
This review refrains from using the traditional separation between CRPS-I and
CRPS-II for various reasons. First, although according to the traditional definition of CRPS-I, evidence of nerve damage is
lacking, no specific clinical or electrodiagnostic criteria have been defined in order to rule out nerve injury. Secondly,
clinical characteristics of CRPS-I patients do not differ from those of CRPS-II patients, which suggests that these two groups
share similar pathophysiological mechanisms.
Signs and symptoms of CRPS can be categorized into autonomic, sensory, motor,
and trophic disturbances. Abnormalities of color and temperature of the skin, sweating, and edema characterize the autonomic
dysfunction. For most CRPS patients, stimulus-independent persistent pain is the most troublesome feature. In addition to
stimulus-independent persistent pain, a wide range of stimulus-induced sensory abnormalities may be present, including hyperalgesia,
allodynia, hyperpathia, and slow temporal summation of mechanical allodynia. Hyperalgesia and allodynia may result from thermal
as well as mechanical stimuli. Hyperesthesia, hypesthesia, and paresthesia have also been reported. All of these sensory abnormalities
may be exacerbated by stress, exercise, or cold. The motor disorder may consist of a limited range of active movement, weakness,
easy fatigability, dystonia, paresis, and altered reflexes. Some patients develop muscle spasms or tremor of a limb. There
may be alterations in growth rate of the hair and nails. The skin may become smooth and glossy, with a decrease or loss of
normal wrinkles and creases. Rarely, skin pigment changes and/or ulcers are observed. Trophic changes of other tissues may
also occur, including atrophic changes of subcutaneous tissues (pencil-point or tapered digits), and muscular wasting. At
end-stages of the syndrome, contractures of tendons often occur and joints may become ankylosed.
The onset of symptoms of CRPS may vary from immediately to several weeks after
injury. When the initiating event is non-traumatic, the onset may be slower and more insidious. The clinical course of CRPS
has been divided into three stages: first (acute or hyperemic), second (dystrophic or ischemic), and third (atrophic). Various
studies have demonstrated skin blood flow abnormalities, not only in the clinically affected, but also in the clinically unaffected
extremity. The blood flow abnormalities are solely of microcirculatory origin. Laser Doppler flowmetry enable non-invasive
evaluation of the skin microcirculation. Another means of studying skin blood flow non-invasively involves capillary (video)
The ability to diagnose CRPS depends primarily on clinical assessment. There are
no consistent routine laboratory findings in these patients. X-ray studies have been used. Sensitivity and specificity of
x-ray in CRPS patients have been reported to be 69 and 71%, respectively. The percentage of CRPS patients demonstrating electromyography
and nerve conduction velocity abnormalities usually ranges from 50-90%. Thermography and three-phase bone scanning may also
be of help in establishing the diagnosis. Histopathological findings have also been reported.
Microcirculatory abnormalities similar to those observed in CRPS patients may
occur in various other diseases. Angiography and Doppler ultrasonography are available in order to exclude the presence of
major artery disease.
The most effective preventative measure is efficient control of pain and early
mobilization. An effective treatment of CRPS is early recognition and treatment since patients with long-standing duration
of disease are less likely to respond well. Physical therapy, corticosteroids, and transcutaneous nerve stimulation have been
used with some success. The only therapy found to be effective for CRPS in large studies is aimed at interruption of the activity
of the sympathetic nervous system (SNS). Methods include Bier block, paravertebral sympathetic ganglion blockade, and alpha-adrenergic
blockade. The pathophysiological mechanisms underlying CRPS are felt to be due to altered (efferent) function of the SNS and
neurogenic inflammation of sensory nerves. It is thought that neuropeptides released by excitation of sensory nerves may induce
vasodilatation, increase vascular permeability, and excite surrounding sensory nerve fibers. At the level of the central nervous
system, it has been suggested that the increased input from peripheral nociceptors alters the central processing mechanisms.
Future therapeutic modalities for CRPS patients include continued research on blockade of adrenoceptors and capsaicin to decrease
neurogenic inflammation. Neuropeptide-receptor blockers may reduce neurogenic inflammation.
Journal: Vasc Med, 3(3):207-214, 1998.
79 References Resident General Surgery, Dept of General Surgery, University Hospital Maastricht, P.O. Box 5800, 6202
AZ Maastricht, The Netherlands (Dr HAJM Kurvers) GM.02 JL9912/192 ©1999
Truths, errors, and lies around “reflex
sympathetic dystrophy” and “complex regional pain syndrome”.
|Many patients complain of chronic “neuropathic” pains, particularly
following acute physical injury. These pains are often associated with positive or negative motor and sensory symptoms and
related psychophysical signs which render the patients neurological. Experimental physical trauma to animals result in predictable
motor, sensory, and vasomotor dysfunction, and even pain behavior, all of which tends to recover within weeks through natural
Patients who display variations or permutations of such general clinical profile
may harbor organic structural neurological damage or a somatoform pseudoneurological disorder, fraudulent malingering, the
bizarre Munchausen’s condition, or a borderline personality with associated self-infliction of physical damage. Unfortunately,
litigation and compensation issues tend to perpetuate both complaints and medical management, as the psychobiosocial scenario
may become contaminated with secondary gain agendas from the patient and tertiary gain from health care providers or lawyers.
Various treatment modalities may dramatically relieve the subjective or psychophysical
reflex sympathetic dystrophy (RSD) symptoms. Unfortunately, recurrence or “metastases” are almost the rule. Placebo
response was never factored into the “diagnostic-therapeutic block” paradigm until the last decade. Iatrogenesis
is inevitably part of the management outcome of RSD/complex regional pain syndrome (CRPS) patients. It is an error to assume
that patients who display the clinical profile of RSD/CRPS have a discrete disease with one common etiology and definable
pathophysiological mechanism leading to neurological manifestations. They merely harbor a nonspecific symptom complex with
any possible variety of abnormal physiological or psychological backgrounds. It is a classic fallacy to assume that behind
these patients’ pains and motor and sensory symptoms, there is a unique abnormal mechanism by which the sympathetic
system causes not only the objective circulatory changes but also, indirectly, the painful neurological dysfunction. Errors
include historical misinterpretation of vasomotor signs in symptomatic body parts and misconstruing symptomatic relief after
“diagnostic” sympathetic blocks, due to lack of consideration of the placebo effect which explains the outcome.
It is also not true that sympatholysis may specifically cure patients with unqualified “RSD.”
As extrapolated from observations in animals with gross experimental nerve injury,
adducing hypothetical, untestable, secondary central neuron sensitization to explain psychophysical sensory-motor complaints
displayed by patients with blatantly absent nerve fiber injury is not an error, but a lie. While conceptual errors are not
only forgivable but natural to inexact medical science, lies, particularly when entrepreneurially inspired, are condemnable
and call for peer intervention.
Journal: J Neurol, 246(10):875-9, 1999. 38 References
Department of Neurology, Good Samaritan Hospital and Oregon Health Sciences University, 1040 NW 22nd Ave N-460, Portland,
OR 97210 (JL Ochoa, MD)
Complex regional pain syndrome.
|Complex regional pain syndrome (CRPS), formally known as reflex sympathetic
dystrophy (RSD), is a regional, post-traumatic, neuropathic pain problem that most often affects one or more limbs. The nosology
and terminology of post-traumatic limb pain have undergone a series of changes that have led to considerable confusion and
controversy regarding the diagnosis and treatment of CRPS. The most common popular contemporary label is RSD, and this terminology
is based on the notion that a pathologic sympathetically maintained reflex arc is involved in the generation and perpetuation
of pain. Recent studies have shown that the sympathetic nervous system is not necessarily involved in every case and that
a "reflex arc" has not been demonstrated. To bring some order and uniformity to this problem, CRPS has been subdivided into
type 1 and type 2. The clinical features of the two types are identical, the distinguishing feature being the presence of
a major peripheral nerve injury in patients with type 2.
Concerning diagnosis, no specific test is available for CRPS, and no pathognomonic
clinical feature identifies this condition. Rather, identifying a constellation of history, clinical examination, and supporting
laboratory findings make the diagnosis. Most patients with CRPS have an identifiable inciting or initiating injury, which
may be trivial or severe. The key features are pain, allodynia and hyperalgesia, abnormal vasomotor activity, and abnormal
sudomotor activity persisting beyond the period of normal healing. Pain usually spreads beyond the area of the initial injury
and, in its most severe form, may involve the entire limb and, rarely, the contralateral limb.
Symptoms of sympathetic dysfunction may be present and may manifest as vasomotor
and/or sudomotor instability. The symptoms typically come and go and, in later stages, may not be present at the time of the
initial examination. The typical signs are color changes, temperature changes, and excessive sweating. Hyperhidrosis is a
common finding early in the course of CRPS. If pain is relieved by sympathetic blockade, it is regarded as sympathetically
maintained. Pain that is not relieved by sympathetic blockade is known as sympathetically independent pain. Sympathetically
maintained pain can convert to sympathetically independent pain and, in the authors' experience, "pure" sympathetically maintained
pain is rare. Patients who have had symptoms for months to years may have severe brawny edema, muscle atrophy and contractures,
and marked cyanosis of the limb. Treatment at this late stage is often unsuccessful.
Although no specific diagnostic test is available for CRPS, several tests can
be supportive in making the diagnosis. The most important role of testing is to help rule out other conditions. Some of the
testing used includes vascular studies, electrodiagnostic studies, radiographic studies, and blood tests. Plain radiographs
can show patchy osteoporosis as early as two weeks after the onset of CRPS.
At present, sympathetic blocks, once considered essential in the diagnosis, are
not required to be positive for a diagnosis of CRPS. Since some patients do not have sympathetic dysfunction, it is important
to identify them because of therapeutic implications. A pharmacological sympathetic block can be performed with an intravenous
infusion of phentolamine; however, this technique has not gained widespread use. The more common and time-tested approach
is to perform a local anesthetic sympathetic trunk block: a lumbar paravertebral sympathetic block for the lower extremity
and a stellate ganglion block or upper thoracic sympathetic block for upper extremity symptoms. Although it is vital to obtain
evidence of satisfactory sympathetic block and to demonstrate the absence of somatic nerve block for diagnosis, occasionally
in treatment sympathetic and somatic block may be necessary for advanced disease.
Successful treatment of CRPS depends on an aggressive and multidisciplinary approach.
Since pain and limb dysfunction are the major clinical problems, physical rehabilitation and pain control are the main treatment
objectives. Comorbidities such as depression, sleep disturbance, anxiety, and generalized physical deconditioning should be
treated. This means that a patient's pain and disability must be treated in a manner that allows rehabilitation to proceed.
Drug therapy, including anti-depressant agents, gabapentin, corticosteroids, topical analgesics, opioids, and other drugs,
has been used successfully. Regional anesthesia techniques, including sympathetic blocks and somatic blocks, are required
in some cases. Neuromodulation, including spinal cord stimulation and intrathecal analgesia, have been used. Intrathecal baclofen
has been shown to decrease the dystonia, improve functioning, and occasionally reduce pain levels.
Like most medical conditions, early diagnosis and treatment of CRPS increase the
likelihood of a successful outcome. Accordingly, patients with clinical signs and symptoms of CRPS after an injury should
be referred as soon as possible to a physician with expertise in evaluating and treating this condition. Mild cases respond
to physical therapy and physical modalities. Mild to moderate cases may require adjuvant analgesia, such as gabapentin and/or
an anti-depressant medication. An opioid should be added to the treatment regimen if these medications do not provide sufficient
analgesia. Patients with moderate to severe pain and/or sympathetic dysfunction require regional anesthetic blocks to participate
in physical therapy. Most patients improve with early treatment. A small percentage of patients develop refractory, chronic
pain and require long-term multidisciplinary treatment, including physical therapy, psychological support, and pain relieving
measures. A suggested treatment algorithm is given.
Journal: Mayo Clin Proc, 77(2):174-180, 2002. 10 References
Reprint: Div of Pain Medicine, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (RH Rho, MD)
PAIN VERSUS RSD
There are many kinds of nerve
fibers. Two that are easy to understand are the motor fibers, which let us move and the sensory fibers that let us feel. Another
important group of fibers that is harder to understand includes the sympathetic nerves. These nerves arise from ganglia, which
are collections of the fibers located outside of the spinal cord.
The ganglia function independently
(automatically) from the rest of the nervous system.
The sympathetic nerves send
branches to many places, including internal organs, coverings of the spinal cord (dura), intervertebral disks, muscles, tendons,
ligamentous structures, and blood vessels. The job of the sympathetic nerve is to tell the brain and spinal cord when something
goes wrong with any of the tissues that it innervates.
The injury may be major or
minor in severity. When you sprain an ankle, first you feel a sharp electric pain, and then you feel a burning pain. The sharp
pain comes from the fast pain fiber, and the second burning pain comes from the sympathetic nerve fiber. Usually, over time,
this burning pain will stop. THIS TYPE OF SYMPATHETIC PAIN IS ENTIRELY NORMAL.
Sometimes the burning will
not stop. When this happens, people often have a hard time describing where their pain begins or ends, but usually can tell
you that the cold or shifts in the weather makes it worse. They may have noticed that since they hurt themselves the painful
part always feels cold. As it becomes more severe their skin can become sweaty, and they won't want to move the painful part
(stage 1). When it is more severe still, they do not want anyone (or anything) to touch them where they hurt.
Unfortunately, most health
care providers are not familiar with the proper diagnosis and treatment of sympathetic pain, however when they hear this kind
of complaint, they should at least begin to think about it. If they do, often a diagnosis of Reflex Sympathetic Dystrophy
(RSD) is made.
In true RSD, there is a decrease
in the local blood flow of the injured part. If allowed to persist, then the cold, sweaty and swollen skin of stage 1 progressively
gets worse until there is loss of range of motion or even loss of muscle mass (stage 2). In even more severe cases, the bones
may thin as well (stage 3).
In RSD, the sympathetic nerve
is felt to be overacting. Liken it to a car engine that is dieseling: the ignition is off, yet the engine is still on. In
this case the sympathetic nerve stays on, even when the injury itself is old and no longer represents a new injury.
In the past, diagnostic studies
were not that helpful for this disorder, so most doctors who knew anything about it at all felt that performing a sympathetic
ganglion block could prove a diagnosis of RSD. This block is supposed to stop the ganglion from dieseling, and therefore decreased
pain and increased blood flow should occur once the block is done.
If the desired response did
not occur, then the patient was frequently said to have psychological factors affecting their perception of pain (this was
also the case if no one thought of the diagnosis to begin with). This approach by in large has been a failure. Many people
still complained of pain, and often were felt to have obvious physical signs of injury, even though they did not respond to
blockade. Others had little or no signs of injury, but persisted with their complaints in a consistently reliable manner over
Fortunately, THERE IS NOW
AWARENESS THAT NOT ALL SYMPATHETIC PAIN REPRESENTS RSD. There is also greater understanding of how to use diagnostic studies
to categorize what type of sympathetic pain exists. The two tests that are used to objectify the presence of sympathetic pain
syndromes are bone scans and thermography.
The bone scan is felt to be
more specific, but the thermogram is far more sensitive. In order for a bone scan to be positive, there must be up to 30%
bone loss. If the three-phase study is used, then there must be vasoconstriction (decreased blood flow) of large enough magnitude
to allow for it to be seen on x-ray.
The thermogram shows skin
temperature changes, but does not tell you the source of those changes. While skin temperature is felt to be under the control
of the sympathetic nerve fibers, the study only tells you if it is present or not: there is no specificity as to the underlying
generator (or injury site) causing the change. Further, up to one third show increased, not decreased blood flow.
Clearly waiting for a positive
bone scan is far too late to treat patients with this disorder, and the characteristics of the thermogram require explanation
in order to provide greater utility. With the classification of different types of sympathetic pain, the objective findings
as well as the clinical presentation and response to treatment are now readily identifiable
Nervous System and RSD
This nervous system goes
to all the body structures such as muscles, tendons, ligaments, etc. and organs. When one of these sites receives an injury
it's the sympathetic nervous system's job to monitor the injury and tell the spinal cord and the brain about it. Sometimes
it forgets to stop monitoring the injury. It keeps on running like a car engine that keeps running after being turned off
Symptoms of RSD
1. Cold Hyperalgesia- cold
hurts. Patients feels excessive pain to cold
2. Mechanical Hyperalgesia-Excessive
pain to movement, Movement
stimulates pain. Pressure
from touch hurts.
3. Vasomotor changes- Color
changes. Red or blue skin color.
4. Sudomotor changes - Sweating
and / or swelling.
5. Scleratomally Mediated
6. Thermogaphic Change
7. Sympathetic fiber Hyperactivity
8. Contrature - Lost of range
of motion, muscles atrophy (waste away)
9. Sudeks Atrophy - Bone
loss or thinning
10. - Visceral somatic convergence
- A coming together of the
symoathetic nerve supply
to muscles, tendons, ligaments, etc. and the internal organs
11. Regional or sclerotomal
The Triple C Syndrome occurs
when the C fiber, by reflex becomes super sensitive to an undrlying injury of the "A delta" nerve fiber. The "A delta" nerve
is sensitive to vibration, and therefore people with this problem complain that driving or operating any machinery that vibrates
makes them worse. Since the C fiber is trying to limit the effect of this injury, it intensely fires, causing vasoconstriction.
People with this problem say that (1) cold is painful, (2) cold burns and (3) have cold skin. Thermographic examination shows
localized or regional vasoconstriction. Sympathetic blockade is fruitless as once the block wears off, the C fiber will remain
hyperactive in response to the underlying A delta injury. Treatment should instead be directed toward restoration of the A
delta nerve to normal through "A delta" nerve block, electroceutical application (electrical treatments to restore normal
nerve firing), vasodilation and nerve membrane stabilizing medicines ( Mexitil, Catapress, Tegretol, Dilantin, etc.) by mouth.
1. Cold Hypesthesia - Patients
don't feel the cold and cannot distinguish cold as cold. The patients feels it as something else.
2.Cold Hyperalgesia - Cold
hurts but the patients cannot tell that it's the cold they are feeling.
3. Cold skin
4. Pain burns
5."A delta" Neuropathy - This
is the nerve fiber that is best suited for feeling or experiencing vibration. It doesn't work anymore, the nerve is acturally
6. Denervation supersensitivity
of sympathetic efferents - The sympathetic nerve that supplies the tissue goes wild or becomes super sensitive as a result.
It causes all the blood vessels to constrict. The sympathetic nerve respond to a sympathetic nerve block because it's not
the nerve that's injected.
7. Arteriolar smooth muscle
- vasoconstriction - Tighten or closure of blood vessels.
8. Localized vasoconstrictive
thermographic changes - Cold temperature change in local area around injury.