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Reflex Sympathetic Dystrophy Syndrome (RSD) Complex Regional Syndrome (CRPS) |
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Reflex sympathetic dystrophy syndrome is a disease that is poorly understood by patients, their families and health care professionals. In some cases the disease is mild, in some it is moderate and others it is a severe condition. |
REFLEX
SYMPATHETIC DYSTROPHY SYNDROME
(RSD/CRPS)
Reflex Sympathetic Dystrophy Syndrome (RSD) is also known as Complex
Regional Pain Syndrome (CRPS). RSD/CRPS is a multi-symptom, multi-system,
syndrome usually affecting one or more extremities, but may affect virtually
any part of the body. Although it was clearly described 125 years ago by Drs.
Mitchell, Moorehouse and Keen, RSD/CRPS remains
poorly understood and is often unrecognized.
The best way to describe RSD/CRPS is in terms of an injury to a
nerve or soft tissue (e.g. broken bone) that does not follow the normal healing
path. The development of RSD/CRPS does not appear to depend on the magnitude of
the injury. In fact, the injury may be so slight that the patient may not
recall ever having received an injury. For reasons we do not understand, the
sympathetic nervous system seems to assume an abnormal function after an
injury. There is no single laboratory test to diagnose RSD/CRPS. Therefore, the
physician must assess and document both subjective complaints (medical history)
and, if present, objective findings (physical examination), in order to support
the diagnosis. There is a natural tendency to rush to the diagnosis of RSD/CRPS
with minimal objective findings because early diagnosis is critical. If
undiagnosed and untreated, RSD/CRPS may spread, making the rehabilitation
process a much more difficult one. If diagnosed early,
physicians can use mobilization of the affected extremity (physical therapy)
and sympathetic nerve blocks to cure or mitigate the disease. If untreated, RSD/CRPS can become extremely expensive due to
permanent deformities and chronic pain. There are no studies showing
that RSD/CRPS affects the patientís life span. The potential exists for
long-term financial consequences. At an advanced state of the illness, patients
may have significant psychosocial and psychiatric problems,
they may have dependency on narcotics and may be completely incapacitated by
the disease. The treatment of patients with advanced RSD is a challenging and
time-consuming task.
DIAGNOSIS
If one can demonstrate major nerve damage associated with the
development of RSD/CRPS symptoms, the condition is called complex regional pain
syndrome (CRPS) type II or causalgia. Generally, causalgia provides more objective evidence of disease due
to neurological changes (numbness and weakness).
The terms complex regional pain syndrome (CRPS) type I and type II
have been used since 1995, when the International Association for the Study of
Pain (IASP) felt the respective names reflex sympathetic dystrophy and causalgia were inadequate to represent the full spectrum of
signs and symptoms. The term "Complex" was added to convey the
reality that RSD and Causalgia express varied signs and symptoms.İ Many publications, particularly older one,
still use the names RSD and Causalgia. To facilitate communication and
understanding the designation RSD/CRPS is generally used throughout this
document. The principles applicable to the diagnosis and management of RSD are
similar to those principles applicable to the diagnosis and management of
Causalgia.
To make the early diagnosis of RSD/CRPS, the practitioner must
recognize that some features/manifestations of RSD/CRPS are more characteristic
of the syndrome than others, and that the clinical diagnosis is established by
piecing each bit of the puzzle together until a clear picture of the disorder
emerges. Often the physician needs to rule out other potentially
life-threatening disorders that may have clinical features similar to RSD/CRPS,
e.g. a blood clot in a leg vein or a breast tumor spreading to lymph glands can
cause a swollen, painful extremity. Indeed, RSD/CRPS may be a component part of
another disease, (e.g. a herniated disc of the spine, carpal tunnel syndrome of
the hand, heart attack). Thus, treating RSD/CRPS will often be directed to
treating clinical features rather than a well-defined disease. When RSD/CRPS
spreads the diagnosis can be more complicated. For example, if it spreads to
the opposite limb, it may be more difficult to establish a diagnosis because
there is no normal side (control) to compare for objective findings. On the other
hand, the spreading of RSD/CRPS symptoms may actually facilitate the diagnosis
of RSD/CRPS because spreading symptoms is a characteristic of the disorder.
Legal Issues
Many patients who develop RSD/CRPS as the result of an injury do
so in the context of legal liability. Some patients can be expected to defend
their rights in courts of law. It is not uncommon for the defendant to accuse
the patient of faking their condition, especially if there are no objective
findings for RSD/CRPS documented on the medical record. Therefore, the
evaluating physician must assess more than just subjective complaints (medical
history). The physician must aggressively seek and document objective findings.
For example, about 80% of RSD/CRPS cases have differences in temperature in
opposite sides that may be either colder or warmer. These temperature changes
may be associated with changes in skin color. Furthermore, the temperature
differences are not static. The skin temperature can undergo dynamic changes in
a relatively short period of time (within minutes) depending critically on room
temperature, local temperature of the skin and emotional stress. In some cases,
the differences in temperatures may fluctuate spontaneously even without any
apparent provocation.İ Thus, the objective
finding of differences in temperature and color of the skin can be missed by
the physician if only a single physical examination is made. A useful and
relatively inexpensive instrument to have available at the time of the physical
examination is a portable infrared thermometer to measure differences in skin
temperature. Changes in skin temperature and color are only two examples of
several objective findings that should be sought in the patients with RSD/CRPS.
Making the Diagnosis of RSD/CRPS
The diagnosis of RSD/CRPS can be made in the following context. A
history of trauma to the affected area associated with pain that is
disproportionate to the inciting event plus one or more of the following:
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Abnormal function of the sympathetic nervous system. |
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Swelling. |
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Movement disorder. |
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Changes in tissue growth (dystrophy and atrophy). |
Thus patients do not have to meet all of the clinical manifestations
listed above to make the diagnosis of RSD/CRPS. The new CRPS classification
system acknowledges this fact by stating that some patients with RSD/CRPS may
have a third type of CRPS by categorizing it as "otherwise not
specified". There seems to be a small group of patients whose pain
following trauma resolves over time, leaving the patient with a movement
disorder. The pain and symptoms of RSD/CRPS may exceed both the magnitude and
duration of symptoms expected from the normal healing process expected from the
inciting event. Similarly, the RSD/CRPS diagnosis is precluded by the existence
of known pathology that can be explained by the observed symptoms and degree of
pain. There are "grades" of this syndrome described in the literature
with symptoms ranging from minor to severe.
Clinical Features of RSD/CRPS
1.
Pain ñ The hallmark of RSD/CRPS is pain and mobility problems
out of proportion to those expected from the initial injury. The first and
primary complaint occurring in one or more extremities is described as severe,
constant, burning and/or deep aching pain. All tactile stimulation of the skin
(e.g. wearing clothing, a light breeze) may be perceived as painful (allodynia). Repetitive tactile stimulation (e.g. tapping on
the skin) may cause increasing pain with each tap and when the repetitive
stimulation stops, there may be a prolonged after-sensation of pain (hyperpathia). There may be diffuse tenderness or
point-tender spots in the muscles of the affected region due to small muscle
spasms called muscle trigger points (myofascial pain syndrome). There may be
spontaneous sharp jabs of pain in the affected region that seem to come from
nowhere (paroxysmal dysesthesias and lancinating
pains).
2.
3.
4.
5.
a.
b.
c.
6.
7.
RSD/CRPS may present in three stages:
The staging of RSD/CRPS is a concept that is dying. The course of
the disease seems to be so unpredictable between various patients that staging
is not helpful in the treatment of RSD/CRPS. Not all of the clinical features
listed below for the various stages of RSD/CRPS may be present. The speed of
progression varies greatly in different individuals. Stage I and II symptoms
begin to appear within a year. Some patients do not progress to Stage III.
Furthermore, some of the early symptoms (Stage I and II) may fade as the
disease progresses to Stage III.
STAGE I
1. Onset of severe,
pain limited to the site of injury
2. Increased
sensitivity of skin to touch and light pressure (hyperesthesia).
3. Localized swelling
4. Muscle cramps
5. Stiffness and
limited mobility
6. At onset, skin is
usually warm, red and dry and then it may change to a blue (cyanotic) in
appearance and become cold and sweaty.
7. Increased
sweating (hyperhydrosis).
8. In mild cases
this stage lasts a few weeks, then subsides spontaneously or responds rapidly
to treatment
1.
Pain
becomes even more severe and more diffuse
2.
Swelling
tends to spread and it may change from a soft to hard (brawny) type
3.
Hair may
become coarse then scant, nails may grow faster then grow slower and become
brittle, cracked and heavily grooved
4.
Spotty
wasting of bone (osteoporosis) occurs early but may become severe and diffuse
5.
Muscle
wasting begins
1.
Marked
wasting of tissue (atrophic) eventually become irreversible
2.
For many
patients the pain becomes intractable and may involve the entire limb.
İİİİİİİİİİİİİİİİİİİİİİİ A
small percentage of patients have developed generalized RSD affecting the
entire body.
Some other names given to this syndrome:
1.
Causalgia (Minor or Major)
2.
Sudeckís Atrophy
3.
Post Traumatic Dystrophy (Minor or Major)
4.
Shoulder Hand Syndrome
5.
Reflex Neurovascular Dystrophy
1. İİİ The
exact prevalence of RSDSA is unknown; however, data from several studies
suggest it is more frequent than commonly believed.
2. İİİ Both
sexes are affected, but the incidence of the syndrome is higher in women.
3. İİİ The
RSD/CRPS Databank shows the average age to be in the mid thirties.
İİİİİİİİİİİİİİİİİİİİİİİ There
is increasing evidence that the incidence of RSD/CRPS in adolescents and young
adults is on the rise.
1. A number of precipitating factors have been
associated with RSD/CRPS including:
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Trauma (often minor) ranks as the leading provocative event |
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Ischemic heart disease and myocardial infarction |
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Cervical spine or spinal cord disorders |
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Cerebral lesions |
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Infections |
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Surgery |
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Repetitive motion disorder or cumulative trauma, causing
conditions such as carpal tunnel. |
However, in some patients a definite precipitating
event cannot be identified.
Cause of RSD/CRPS
Current research suggests that the
mechanism by which an injury triggers RSD/CRPS is unclear. Activation of the
sympathetic nervous system following an injury is part of a fright-flight
response to an emergency situation. This response is very important for
survival. For example, firing of sympathetic nerves causes blood vessels in the
skin to contract, forcing blood deep into muscle and enabling the victim to use
his muscle to get up after an acute injury and escape from further danger. Also
the decreased supply of blood to the skin reduces blood loss through
superficial injuries that may occur on the surface of the body. Ordinarily, the
sympathetic nervous system shuts down within minutes to hours after an injury.
For reasons we do not understand, individuals who go on to develop RSD/CRPS,
the sympathetic nervous system appears to assume an abnormal function.
Theoretically, this sympathetic activity at the site of injury could cause an
inflammatory response causing the blood vessels to spasm leading to more
swelling and pain.İ The events could lead
to more pain, which triggers another response, establishing a vicious cycle of
pain.
Laboratory Diagnostic Aids:
There is no laboratory test that can stand alone as proof
of RSD/CRPS. However, there are a couple of tests (thermogram,
Laser Doppler flowmetry, and bone scan), which can be useful in providing
evidence for RSD/CRPS.
Treatment
The single most important modality for
treating the patient with RSD/CRPS is education. The informed consent process
should be the focus of education. The physician defines the potential benefits,
risks, alternatives, and costs. From the start, the therapeutic goals must be
defined and accepted by the patient:
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Educate About Therapeutic Goals |
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Encourage |
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Minimize Pain |
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Determine the Contribution of the Sympathetic Nervous System to
the Patientís Pain |
The cornerstone in the treatment of
RSD/CRPS is normal use of the affected part as much as possible. Therefore, all
modalities of therapy (drugs, nerve blocks, TENS, physical therapy, etc.) are
employed to facilitate movement of the affected region of the body. Although
physical therapy is an important treatment modality, significant misuse and
overuse of this modality may occur. Often the physical therapist will treat the
patient with RSD/CRPS the same as a stroke or a nerve plexus injury, (which
will fail due to extreme pain with passive manipulation). The primary goal of
the physical therapist should be to teach the patient how to use their affected
body part through activities of daily living. Swimming pool exercises are very
helpful, especially for RSD/CRPS of the lower extremity where weight bearing
can be problematic. The goal of physical therapy should be to create
independence from the health care system in the shortest period. Learning that
"to hurt is not to harm" is difficult, but it is essential to avoid reinjury.
Learning the
non-protective nature of pain due to RSD/CRPS takes time. For patients who
are significantly impaired in their ability to mobilize their extremity, it is
urgent to offer the patient the opportunity to determine the contribution of
their sympathetic nervous system to their pain. This is accomplished by a
sympathetic nerve block to the affected extremity. Future therapeutic options
for the patient will depend on whether their pain is determined to be
sympathetically maintained pain (SMP) or sympathetically independent pain
(SIP). Published reports suggest that the best response to sympathetic blocks
will occur if the blocks are given as soon as possible during the course of the
disease.
The "LETíS TRY THIS NOW"
approach is to be deplored because it indicates that the physician has not
defined a strategy to achieve specific therapeutic goals in the shortest period
of time. It also adds to the confusion, frustration, anxiety and depression of
the patient, which may intensify the patient's pain and adversely affect the
doctor-patient relationship.
Initiate the safest, simplest, and most cost-effective therapies first. If the
patient fails to progress in mobilizing the extremity, it is essential to offer
the patient a series of 3 sympathetic blocks immediately. The purpose of the
sympathetic blocks is three-fold: to treat, to diagnose if the pain is
sympathetically maintained and to provide prognostic information. The
sympathetic block provides a prognostic indicator if sympathectomy
or other treatment modalities would be the next appropriate step. Sympathetic
blocks are discussed in detail below.
After the
physician has completed a defined course of treatment (e.g. a series of 3-6
sympathetic blocks), it would be helpful to prepare an update report that would
document the patientís response to the course of treatment. The report
should reflect a basis for further treatment and it should address future
rehabilitation needs. An update report should address five areas of care:
1.
Procedures
(e.g. nerve blocks)
2.
Medications
3.
Physical/occupational
therapy
4.
Psychosocial
issues
5.
New
laboratory tests or consults
Patients with severe, advanced stage RSD/CRPS usually undergo a psychosocial
evaluation during the series of sympathetic blocks or prior to offering the
patient more invasive treatments. In some cases, a formal psychosocial
evaluation should be initiated much earlier in the course of treatment. For
example, children with RSD/CRPS may require a thorough evaluation to determine
the family support structure and the coping mechanisms needed by the family for
optimal rehabilitation of the child. The psychosocial evaluation should always
be done by an expert in chronic pain and should always include an assessment of
pain coping skills and drug abuse potential. Stress is a known cause of
exacerbation of this disease, making emergency treatment more necessary. The potential for committing suicide needs
to be assessed. The patient may need to participate in a formal pain
management program as an outpatient or an inpatient. Chronic pain patients
referred for a psychosocial evaluation tend to be defensive. An MMPI or other
psychological test can help identify the psychosocial problems. Patients must
be properly motivated to improve their coping skills; otherwise, application of
these psychosocial modalities is a waste of time. Relaxation techniques (e.g.
breathing exercises) as well as biofeedback and self-hypnosis may be
appropriate treatment modalities for some patients.
Try to initiate sequential trials for each modality of therapy. The application
of multiple therapies at the same time, a shotgun approach, makes it almost
impossible to evaluate and optimize an individual therapy for safety and
efficacy. Patients must be advised that the optimal dose for medications varies
greatly among patients. Therefore, it is usually necessary to gradually
increase the dose of their medication to the point of significant toxicity in
order to determine optimal dose. The dose is then reduced to the next lower
level. Thus it is important for the patient to become familiar with all of the
potential side effects of a medication before trying it. Sequential trials with
many different drugs may be required to determine the best medication for the
patient.
Medications are generally prescribed
according to the following characteristics of the pain:
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Constant pain |
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Pain causing sleep problems |
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Inflammatory pain or pain due to recent tissue injury |
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Spontaneous jabs (paroxysmal dysesthesias
and lancinating pain) |
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Sympathetically maintained pain (SMP) |
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Muscle cramps |
Medications used to treat chronic pain:
"Off-labeling"
prescribing means that the U.S. Food and Drug Administration (FDA) approved the
medication for one purpose, but physicians may use it for another. For example,
aspirin is a pain medication but it can also be used to decrease the risk of a
heart attack by inhibiting the aggregation of platelets. Off-label prescribing
is a common practice in treating various chronic pain problems. Some of these
drugs have been proven to be effective in decreasing pain due to nerve injury
(neuropathic pain) in well-controlled clinical trials. Since RSD/CRPS is
believed to be caused by nerve injury (neuropathic pain), these drugs are used
to treat this condition as well. The patient should consider weaning themselves
from these various medications periodically with the treating physicianís
knowledge to determine for themselves that the
medication is actually helping to alleviate their symptoms. Depending on the
dose, some medications may need to be weaned slowly (e.g. narcotics, Baclofen) to minimize withdrawal symptoms.
For constant pain associated with inflammation:
Nonsteroidal anti-inflammatory agents (e.g.
aspirin, ibuprofen, naproxen, indomethacin, etc).
Agents acting on the central nervous system by
an atypical mechanism (e.g. tramadol)
For constant pain or spontaneous (paroxysmal) jabs and sleep disturbances;
Anti-depressants (e.g. amitriptyline,
doxepin, nortriptyline, trazodone, etc)
Oral lidocaine (mexilitine
- some what experimental)
For spontaneous (paroxysmal) jabs
Anti-convulsants (e.g.
carbamazepine, gabapentin
may relieve constant pain as well)
For widespread, severe RSD/CRPS pain, refractory to less aggressive therapies
Oral opioid. The use of opioids (e.g. narcotics with names such as Darvon, Vicodin, Lortab, Percocet, morphine,
codeine, etc) to treat RSD/CRPS is debated and there are potential hazards.
Therefore, in order to ensure appropriate informed consent, it is recommended
that the patient sign a doctor-patient "contract/agreement."
For the treatment of sympathetically maintained pain (SMP)
Clonidine Patch. Studies suggest that clonidine
may decrease pain in RSD/CRPS by inhibiting the sympathetic nervous system.
Klonopin (clonazepam)
Baclofen
Capsaicin cream. (This medication is applied to the skin and
behaves like hot peppers. The effectiveness of capsaicin cream in the treatment
of RSD/CRPS has not been determined).
Lidocaine patch.
Patients need to be educated on how to use their affected body part through
activities of daily living. For example, for lower extremity RSD/CRPS, patients
may need to be taught weight bearing versus non-weight bearing exercises.
Hydrotherapy is usually medically necessary for muscle (myofascial) pain and
spasms. Application of pressure (massage) and/or moist heat applications can
sometimes relieve severe muscle cramps. The physical therapist can also teach
the patient how to use a TENS unit (a noninvasive electrical device that
stimulates the surface of the skin). Pool therapy can be very effective for
improving mobility.
There are three reasons to consider sympathetic blockade to facilitate the
management of RSD/CRPS. First, the sympathetic block may provide a permanent
cure or partial remission of RSD/CRPS. Second, by selectively blocking the
sympathetic nervous system the patient (and physician) will gain further
diagnostic information about what is causing the pain. The sympathetic block
helps determine what portion of the patientís pain is being caused by
malfunction of their sympathetic nervous system. Third, the patientís response
to a sympathetic block provides prognostic information about the potential
merits of other treatments.
If sympathetic blocks are not properly
performed and evaluated, time and money will be wasted, and
diagnostic-prognostic information will be lost. A good sympathetic block should
increase the temperature of the extremity without producing increased numbness
or weakness. The sensation of warmth tells the patient that they have had a
sympathetic block. If the block causes numbness or weakness, more than just the
sympathetic nerves were blocked and the patient will get an overestimation of
the amount of their pain that is contributed by their sympathetic nervous
system; hence, the diagnostic and prognostic value of the nerve block would be
lost. The amount of pain relief and improvement in range of motion and in
exercise tolerance should be noted by the patient and recorded by the
physician. This information about the patientís response to sympathetic
blockade will serve as a prognostic indicator for rehabilitation following the
series of sympathetic blocks and it will help the patient decide if a permanent
block (destruction of the nerve by sympathectomy)
would be appropriate. Also, the information will aid in directing future medications
in a more rational manner. Some patients will experience a "booster
effect" with each sympathetic block, i.e. each successive sympathetic
block in the series provides greater and greater pain relief and improvement in
exercise tolerance. The maximum sustained benefit from a series of sympathetic
blocks is usually apparent after a series of 3-6 blocks. Even if the original
site is unresponsive to sympathetic blockade, future exacerbation of RSD/CRPS
symptoms at the same site or at a distant site may be responsive to 1-3
sympathetic blocks. THE GOAL IS ALWAYS TO TREAT BUT DONíT OVER TREAT.
Sympathetic blocks are usually performed
by a pain specialist trained in anesthesia. In experienced hands, these nerve
blocks can be performed with minimal discomfort to the patient with or without
IV sedation. Complications from sympathetic blockade are extremely rare.
However, it is always possible for the local anesthetic to be inadvertently
injected into a blood vessel or into the spinal fluid. If this should happen,
the patient may temporarily become weak and lose consciousness. For safety
reasons, sympathetic blocks are always performed under conditions where the
vital signs (blood pressure and breathing) can be monitored closely. Patients
should not eat for 6 hours prior to a sympathetic block.
A sympathetic block of the upper
extremity is called a stellate ganglia block (SGB). The SGB is performed by
inserting a small needle along side the windpipe (trachea). Patients are
informed that they may notice a temporary change in the tone of their voice
following the block because some of the local anesthetic may partially numb the
vocal cords. They are also informed that they should sip fluids and take small
bites of food immediately after the block. The numbness around the vocal cords
temporarily places the patient at a slight risk of coughing in response to
drinking and eating. The patient may also notice a temporary drooping of their
upper eyelid due to the SGB (Hornerís sign). A sympathetic block of the lower extremity
is called a lumbar sympathetic block (LSB). For patient comfort and safety, LSBs should be performed with the aid of a fluoroscope
(X-rays). As noted previously in this document, there may be point-tender spots
in the muscles of the affected region due to small muscle spasms called muscle
trigger points (myofascial pain syndrome). The patient may obtain significant
relief of the diffuse pain due to RSD/CRPS from a sympathetic block but the
pain due to muscle trigger point(s) may persist. Local injection of local
anesthetic into the trigger point region and/or application of physical therapy
techniques after a sympathetic block may be necessary to provide further relief
of pain.
Warning ñ We strongly
caution against allowing any physician without a formal ìInterventional Pain
Management Fellowshipî, to perform any of these procedures. We specifically
recommend not having this, or any other pain management treatments (procedures
or blocks) done by radiologists or other physicians that do not follow up with
the treatment.
If there is a significant decrease in pain following the sympathetic block, the
patient is said to have sympathetically maintained pain (SMP). If there is not
a significant decrease in pain, the patient has sympathetically independent
pain (SIP). Only patients with SMP should be considered for a sympathectomy. Patients are advised to expect no more
relief of their pain from this type of block, i.e. sympathectomy,
than they received from either a SGB or a LSB, nevertheless, the duration
should be longer. Thus the patient must really pay attention to the magnitude
of pain relief and improvement in function following each sympathetic block.
Sympathectomy is a relatively invasive procedure with potential complications
and should be pursued by the patient only if they are certain about the
temporary therapeutic benefits that they received from a series of SGBs or LSBs.
The patient has the choice of dissolving
(destroying) the sympathetic nerves with phenol injected through a needle while
the patient is awake (percutaneous phenol sympathetic neurolysis) or a surgical
sympathectomy under general anesthesia. Other
techniques for sympathectomy have also been used. The
patient must be informed of the pros and cons of each approach.
Post-sympathectomy
pain (neuralgia) is a potential complication of all types of sympathectomy.İ Post-sympathectomy pain is typically proximal to the original
pain (e.g. proximal means that the pain may appear for the first time in the
groin or buttock region for sympathectomy of the
lower extremity and pain in the chest wall region for sympathectomy
of the upper extremity). Patients may think that their RSD/CRPS has spread to a
new region after sympathectomy because the pain feels
similar to their original RSD/CRPS pain. The post-sympathectomy
pain usually resolves on its own or with 1-3 sympathetic blocks. Thus for some
patients, sympathectomy may be a two-step procedure;
destruction of sympathetic nerves followed by a sympathetic block.
Data published by the RSDSA suggests
that sympathectomy in properly selected RSD/CRPS
patients may provide one of the most effective treatments for RSD/CRPS. The
selection criteria for sympathectomy are critical in
achieving long-term success.
The placebo effect (decreased pain due to an inactive treatment such as a sugar
pill) must be considered in the treatment of RSD/CRPS. Although the figure of
33% is commonly quoted in papers and textbooks as the percentage of people who
will respond to a placebo, it is misleading because the "percentage"
varies enormously (from close to 0. to 100%) depending on the exact
circumstances. Physician and patient must have an understanding about the
placebo effect, otherwise the patient is at risk of
being over-treated. Recognition of placebo versus specific pain-relieving
treatment may be difficult, but there are some distinguishing characteristics.
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The greater the invasiveness of the procedure itself, the
greater the placebo effect. |
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The greater the expectation for pain relief, the greater will be
the placebo effect. |
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The placebo tends to be of less duration. For example, close
monitoring of the patient's pain for hours and days after each sympathetic nerve
block has shown that the pain-reducing effect of the saline (placebo)
injection subsides within the first few hours, whereas that of the local
anesthetic injection persists for several days. |
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The placebo tends to be less reproducible with each successive
treatment. |
Therefore, it may be of great potential
therapeutic value to provide each patient with a series of multiple sympathetic
blocks separated by brief intervals (e.g. one to two weeks) simply to determine
whether such blocks are effective treatments.
The time-course of pain relief and
improvement in function must be monitored closely by the patient. The actual
local "anesthetic" effect of a sympathetic block lasts for only a few
hours. But patients with SMP usually experience pain relief that far outlasts
the duration of the local anesthetic effect. This type of extended relief of
pain and improvement in mobility beyond the duration of the nerve block is
believed to indicate an element of "reflex" activity or a
"vicious cycle" in the affected region of the body, either from
muscle spasm or from sympathetic over-activity.
Intentional or not, some patients may
not reliably report the effects of sympathetic blocks. As noted, a good
sympathetic block provides a feeling of warmth that will act as a
"cue." Some patients respond to that change in sensation by
anticipating the results or stating it as a genuinely perceived reduction in
pain. Others may deceitfully report pain relief, since they believe that such a
report is necessary for further treatment, attention, or other desired gain.
Some patients may feel that some "treatment" is better than no
treatment at all, even if the treatment is ineffective.
A sympathetic blocker (alpha adrenergic antagonist), phentolamine,
given I.V. has been advocated as a diagnostic test for SMP. However, false
negative tests have been reported as high as 43%. Moreover, this approach is
somewhat elaborate and requires considerable technician time and expense.İ The phentolamine
test is a diagnostic procedure while a sympathetic block is a diagnostic,
prognostic and therapeutic procedure.İ
However, the phentolamine test may be valuable
treatment option in the situation where a sympathetic block is not possible or
when multiple extremities are involved.
Epidural blocks are effective but less
specific in blocking the sympathetic nervous system and, therefore, they may be
therapeutically useful, but are not as useful for diagnostic and prognostic
purposes. The infusion of local anesthetic through the epidural catheter may
cause temporary weakness in the legs, making walking dangerous. Placement of
long-term epidural catheters to treat RSD/CRPS still occurs in practice.
Perhaps this is because anesthesiologists are more familiar with the epidural
catheter technique than with the selective sympathetic block technique. The
long-term epidural catheter approach is more expensive and patients are placed
at more risk for certain rare life-threatening complications, e.g. infection
(epidural abscess). Nevertheless, short (2-5 days) hospitalization for
continuous epidural infusions may be necessary to break the pain cycle.
Dislodgment of the epidural catheter is a relatively common problem. The use of
a lumbar sympathetic catheter may provide a more specific sympathetic block
than an epidural catheter, but the lumbar sympathetic catheter is more likely
to become dislodged during exercise.İ
There is a place for the use of epidural and lumbar sympathetic
catheters in the treatment of RSD/CRPS but the physician should justify these
techniques on a case-by-case basis.
Another technique used to carry out a
sympathetic block involves the intravenous injection of sympathetic blocking
agents (e.g. guanethidine, bretylium
and clonidine) into an extremity and limiting spread
of the agent to the entire body by applying a tourniquet to the extremity.İ These techniques are called ìBier Blocksî.
This method requires placing an IV in the painful extremity and may be
technically extremely difficult due to severe swelling (edema) of the
extremity. The patient may not be able to confirm that they actually received a
sympathetic block because the "cue", a warming sensation in the
extremity, may not be felt. Furthermore, there is no evidence that this
technique is more effective than the usual sympathetic blocks for the diagnosis
and treatment of RSD/CRPS. The IV tourniquet technique using a sympathetic
blocking agent may be considered as an option for patients who must take blood
thinners (anticoagulants) where a SGB or a LSB may cause major bleeding.
Spinal cord stimulation (SCS) uses low intensity, electrical impulses to
trigger selected nerve fibers along the spinal cord (dorsal columns), which are
believed to stop pain messages from being transferred to the brain. SCS
replaces the area of intense pain with a more pleasant tingling sensation
called paresthesia.İ
The tingling sensation will remain relatively constant and should not
hurt. There is some experimental evidence that SCS may enhance the flow of
blood to the affected extremity by blocking the sympathetic nervous system.
A temporary trial, with a temporary
electrode, should be performed first before implanting permanent electrode(s).
Given that SCS is a relatively invasive, costly procedure and given that
RSD/CRPS patients are often desperate and frustrated,
a baseline psychosocial evaluation that addresses pain management issues should
be done. Although rare, spinal infection and paralysis are potential
complications. The ability to insert the electrode through a small needle has
reduced the risk of the procedure and has facilitated the trial with a
temporary electrode.
Treating RSD/CRPS with SCS poses unusual
clinical and technical problems. RSD/CRPS tends to be an unpredictable disease
from a technical standpoint. The need to focus SCS on the most painful region
must be kept in mind, which is more difficult in RSD/CRPS, because the location
of the worst pain may change. Furthermore, the pain from RSD/CRPS may spread to
distant parts of the body, requiring multiple successive implanted stimulators
to cover the largest possible area. Therefore, even when RSD/CRPS is limited to
one extremity, it is wise to widen stimulation to zones to which the pain might
spread.
Because of the risks and high costs of
spinal cord stimulation, the treatment is reserved for severely disabled
patients. A recent well-controlled study shows that with careful selection of
patients and successful test stimulation, SCS is safe, reduces pain, and
improves the health-related quality of life in patients with severe RSD/CRPS.
Left
upper extremity CRPS patient before (Left) and after (Right) having started
treatment at our facility.
It is well recognized that a single injection of morphine into the spinal fluid
(within the intrathecal space) produces a selective pain-blocking effect on the
spinal cord. This selective effect on the spinal cord spares the patient from
many of the serious side effects caused by morphine when it is given orally
(e.g. sedation). Soon after this discovery, enthusiasm developed to implant
permanent morphine pumps to treat non-cancer chronic pain. This modality is
mostly effective for pain syndromes below the chest. The same complications
sometimes associated with oral morphine use are also found with the morphine pump,
such as development of drug tolerance, nausea, constipation, weight gain,
decreased sex appetite (libido), swollen legs (edema), and increased
sweating.İ In addition, malfunction of
the pump system (dislodgement of the catheter) can be a problem. The implantation
of a morphine pump is a relatively invasive and expensive treatment
modality.İ Because of the risks and high
costs of intrathecal pumps, the treatment is reserved for severely disabled
patients. Studies suggest that with careful selection of patients and
successful trials, intrathecal pumps may reduce pain and improve the quality of
life in patients with localized chronic pain.