a. Heat. Heat may be useful during the times when the affected region is cold and vasoconstriction predominates. Many authorities discourage the use of a whirlpool because the dependent position of the affected area tends to increase edema. Paraffin and fluidotherapy are useful alternatives, and it is useful to combine them with stretching and ROM exercises. The often exquisitely increased sensitivity of these patients to heat must be kept in mind. Some patients may be able to tolerate application of heat only to remote areas. This may lead to vasodilation of the affected areas if thermoregulatory reflexes are even partially preserved.
b. Cold. The application of cold packs may be useful for the warm, hyperemic limb, with caveats similar to those for the use of heat. Again, remote cooling may be useful.
c. Contrast baths. When careful attention is given to determining tolerated temperature, these may be useful in the treatment of pain and edema and may be taken at home.
4. Elevation, decongestive massage, and intermittent Jobst pneumatic compression. These techniques are useful for edema, and the massage also provides desensitization. Again, many patients will have difficulty tolerating massage and compression because of allodynia and hyperpathia. For some patients in whom temporal summation of pain is prominent, pain can be minimized if care is taken to ensure continuous rather than intermittent contact during massage. It has been suggested that deep massage may lead to histamine release and increased inflammation.
For patients who tolerate Jobst compression, this modality should be not be allowed to interfere with mobilization. Compressive garments and wraps if tolerated are advantageous with respect to motility.
5. Range of motion. Movement is necessary to prevent contractures, reduce edema, "gate out" pain, help restore normal neuronal architecture, and strengthen muscles. The necessity of the potentially painful exercises should be explained, and the therapist needs to monitor the patient's response constantly. The exercises should be coordinated with pain treatment and performed at appropriate intervals after pain medication. Failure to tolerate exercise even after that may be an indication for more aggressive treatment, including sympathetic blockade. A stress-loading approach involving compression and distraction while joint movement is minimized has been found to be particularly useful (e.g., scrub and carry for the upper extremity and standing with graduated weight bearing for the lower).
Generally, active and assisted active ROM exercises are emphasized. On those occasions, when it is deemed that passive ROM exercises are indicated, it should be remembered that these are more likely to lead to pain and interference by allodynia. The ideal ROM exercises are those relevant to activities of daily living (e.g., walking with crutches for RSD of the lower extremity).
6. Splinting. Static and dynamic splinting may be useful, but only if employed judiciously. Too many or too complicated splints will overwhelm the patient. Static splints may be necessary to prevent contractures and may be useful at night to prevent joint motion from disturbing sleep. It may also help position the affected areas to allow appropriate strengthening exercises. Of course, they will also contribute to the undesirable sequelae of immobilization if overused. Dynamic splinting, if carefully crafted, may decrease pain through stimulation of large afferents, reduce edema, and maintain ROM. Static progressive splinting is indicated when ROM is limited by contractures and stiffness and pain is relatively quiescent.
7. Ultrasound may be helpful by providing pain relief and inducing vasodilation.
8. Biofeedback may be useful for vasomotor instability and movement abnormalities, including hypertonicity, spasticity, and dystonias.
C. Treatment of movement disorders. Interventions that decrease sympathetic function may be useful in the treatment of tremor but have inconsistent effects on dystonias. Benzodiazepines may be helpful for spasms. Visual and verbal cues may be helpful in cases in which features of neglect are prominent.
D. Psychiatric and psychological interventions. Many patients with RSD present with a history of mistaken diagnoses, perceptions (which may or may not be accurate) that their pain has been dismissed (by professionals and family), irritability, demoralization, and sleep deprivation because of pain. These often lead to anger at the medical system and strained relations between the patient and family members. "Stress," anxiety, and depression, which are common in these patients, are well-known to exacerbate pain from any cause, and because of their effects on the autonomic nervous system (association with increase or dysregulation of circulating catecholamines), they also may play a more specific role in RSD.
Many psychological interventions can be performed by any member of the multidisciplinary team. These include developing a supportive relationship; carefully educating the patient about pain, including explicitly acknowledging its disabling effects and adverse effects on interpersonal relationships; and making the patient aware of the interaction of pain with mood. Certain antidepressant drugs that may be used for sleep and pain also have adrenergic-blocking effects.
Concerns about an associated depression or other psychiatric disorder that perhaps requires treatment with psychotropic agents, behavioral problems that severely compromise the treatment, or medical issues that complicate the use of an antidepressant may indicate the need for a more formal psychiatric consultation. This must be accomplished tactfully and after good rapport has been established (to the extent that this is not prevented by the psychological problems). Both patient and family may resist the suggestion of a psychiatric consult because, in addition to the usual stigma associated with such a consult, they may feel that this is another example of the dismissal of symptoms as being "all in the head." Indeed, this might be a good starting place for psychological education to begin: "Yes, pain is in your head, all of our feelings are in our head. Pain affects mood and mood affects pain. We all have heard stories of soldiers wounded in battle who do not feel the wound until the battle is over. On the other hand, we all know that minor pains (and I'm not talking about RSD) are 10 times more annoying when we're tired or upset." Another approach is to explain that the psychiatrist is a specialist in helping people deal optimally with stressful conditions and that many of the medications they use are effective in treating pain. The psychiatrist may also play a role as a neutral party in helping to monitor the use of narcotics, ensuring that the patient receives adequate dosage yet watching for inappropriate dosage escalation. Support groups may be useful for patient and family. Antidepressants are discussed below.
E. Therapies directed at the nervous system. The importance of factors other than sympathetic function in RSD has been discussed above. Nevertheless, interventions to decrease the activity of sympathetic neurons, such as ganglionic blocks and regional IV catecholamine depletion, still play an important role in assessment (see section V...B...6) and treatment. Again, it must be emphasized that only some of the adrenergic activity in a given region is caused by the local release of catecholamines, the target of these procedures. Circulating catecholamines (which may be increased in response to pain, depression, and anxiety), including norepinephrine released from sympathetic neurons in other regions and epinephrine from adrenal medullary activity, may stimulate the adrenergic receptors relevant to the manifestations of RSD.
a-Adrenergic blockade (e.g., phentolamine) will prevent the action of catecholamines, whether they are locally or systemically produced. Hence, a case could be made for the combined or sequential use of modalities. Somatic blockade may be required for patients in whom a major component of pain is nonsympathetic in origin.
Important note: Any pain relief provided by sympathetic or somatic blockade should be followed immediately by intensive mobilization and other physical therapy modalities.
1. Sympathetic ganglion blockade. Sympathetic blocks with local anesthetic agents are used for both diagnostic and therapeutic purposes. Stellate ganglion block is utilized for the upper extremities. However, as stated above, care must be taken to ensure that blockade of sympathetic nerves to the arm has actually been accomplished, even in the presence of Horner's syndrome. This is indicated by elevation of fingertip temperature by 1° to 3°F venous engorgement, dryness of the skin, and a subjective feeling of warmth. Although many use lidocaine for the initial treatment, bupivacaine block may last considerably longer than lidocaine block. Lumbar (L-2 through L-4) blocks are used for the lower extremities. It is generally agreed that the procedure should be repeated at least three times within 7 to 10 days before it should be considered to have failed. It is often performed even more frequently (every other day) and tapered when the response has plateaued, typically after six to 12 successful blocks.
2. Epidural block. The epidural route is also useful, particularly for the lower extremity, because of the technical difficulties and pain associated with lumbar ganglionic block. Further, the ease and safety of placement of epidural catheters make it an attractive procedure. Continuous epidural blocks may relieve pain even when repeated lumbar blocks have failed to do so. They can be performed quite selectively with respect to level and nature of neurons (sympathetic, somatic, or both). Some groups advocate initial infusion with local anesthetic followed by agents such as narcotics or ketamine; in this way, motor function is left intact so that active ROM exercises can continue. On the other hand, sparing of motor fibers is not as important when this procedure is used to "cover" passive ROM exercises or manipulations. Of course, epidural blocks also have their side effects, including hypotension, urinary retention, and rarely seizures or infection. Respiratory depression is rare unless morphine is used. Recently, epidural clonidine has been used alone and in combination with other agents because its a2-adrenergic agonism will inhibit the release of norepinephrine.
3. Intravenous regional "chemical sympathectomy." In the past, IV regional chemical sympathectomy was recommended for patients in whom sympathetic or somatic ganglion block and epidural block were contraindicated (hypersensitive or on anticoagulants). Additionally, it represented an alternative to surgical sympathectomy in high-risk patients. In chemical sympathectomy, an IV infusion of agents depletes noradrenaline from sympathetic terminals. The agents are confined to the affected region by placement of a blood pressure cuff or other compressive device inflated above systolic pressure proximal to the site of injection. After a period of time, during which the agents are taken up by the sympathetic nerve terminals, the tourniquet is released. However, the place of this procedure in the modern armamentarium remains undefined. As is the case for so many modalities used in RSD, enthusiastic reports are counterbalanced by negative ones. This variability may result from patient heterogeneity and technical factors. Review of the studies indicates variation in the rigor with which sympathetic blockade was demonstrated. Guanethidine and to a lesser extent reserpine were used in virtually all the studies, and these agents are no longer routinely available in the United States. However, bretylium, another catecholamine-depleting agent, has been reported to be safe and efficacious. With respect to technical factors, the simplicity of the technique is more apparent than real. Because of the possibility of side effects (e.g., hypotension) resulting from systemic leakage before and after the cuff is released, this procedure should be carried out with continuous monitoring of vital signs. Electrocardiographic equipment in a suite equipped for resuscitation is mandatory, and a well-functioning IV line should be placed in an uninvolved area. In addition, application of the tourniquet may be quite painful and cause phlebitis.
These regional catecholamine depletion techniques do not relieve pain caused by circulating catecholamines. This problem has been addressed by the use of regional blockade of a-adrenergic receptors. The reversible antagonist phentolamine may be infused regionally in patients who cannot tolerate the marked autonomic side effects accompanying systemic infusion. The use of IV phenoxybenzamine, an irreversible antagonist that should in theory have a longer duration of action, was reported recently. Although the results were positive, the study must be considered preliminary.
4. Intravenous a-adrenergic blockade is the simplest technique to block the effects of circulating and locally produced catecholamines. Infusion of phentolamine and phenoxybenzamine has been used more often as a "diagnostic technique" than as an ongoing treatment because of the autonomic side effects of these drugs when administered systemically rather than regionally. Brief but reproducible and perhaps partial responses to abrogation of sympathetic activity may be indications to consider more permanent and invasive approaches to abrogating sympathetic function.
5. Role of surgical sympathectomy or chemical sympatholysis. Short-lived or partial responses to the above measures have in the past been considered indications for sympatholytic procedures, such as injection of phenol or alcohol into ganglia or surgical sympathectomy. Recently, radiofrequency ganglionic ablation has been reported. These techniques can be guided with imaging. However, their role is controversial because of technical considerations, because the results are irreversible (particularly in the case of surgical procedures), and because pain may paradoxically recur or even increase ("sympathalgia"). The latter may reflect aberrant regeneration or receptor hypersensitivity. Reliance on surgical sympathectomy and sympatholysis has decreased because of the availability of techniques for more continuous sympathetic blockade, the development of newer concepts regarding the importance of nonsympathetic pain in RSD, and the realization that the plasticity of the nervous system allows it to remodel in response to normalization of function and diminution of pain resulting from even temporary interruption of the pain cycle.
6. Somatic blocks. Patients in whom suboptimal pain relief is obtained with the above modalities may have an important nonsympathetic component to their pain and hence may benefit from somatic blocks. For them, continuous infusions may be considered, either directly into the relevant plexus or the epidural space. Again, this procedure is often used to facilitate physical therapy, so it is crucial to coordinate the modalities with respect to timing and technique. For example, lower concentrations of anesthetic (0.125% to 0.25% rather than 0.5% bupivacaine) to minimize motor block are used if active exercises are to be undertaken following the block.
7. Oral adrenergic receptor antagonist. a-Adrenergic blockers (prazosin, phentolamine, phenoxybenzamine, terazosin) have been reported to be useful, although no controlled trials have been performed. Side effects include hypotension, reflex tachycardia, and impaired sexual function. b-Adrenergic blockers (with concern for their well-known side effects) may be used to treat the reflex tachycardia or occasionally alone (propranolol).
8. Clonidine. Clonidine decreases norepinehrine release through its agonist effect on inhibitory a 2-autoreceptors. Oral, transdermal, and epidural routes have been recommended. Aside from its potential to decrease peripheral catecholamines, it is also anxiolytic through a central effect. Hypotension and sedation are major side effects.
9. Anticonvulsants. Carbamazepine (Tegretol) has been used for RSD. Although carbamazepine has been extensively studied in neuropathic pain, it is difficult to use because of its narrow therapeutic margin, profile of side effects (most notably central nervous system, liver, and blood; rarely, syndrome of inappropriate secretion of antidiuretic hormone, or SIADH), and myriad drug interactions (it is a potent enzyme inducer). Its quinidine-like properties must be remembered in patients with heart disease who are taking anti-arrythmics and related compounds. Gabapentin (Neurontin) is a more recently introduced anticonvulsant that does not have these disadvantages but has not been as extensively used in the treatment of pain. Phenytoin and valproate have been used. As is typical for RSD, reports are anecdotal.
10. Antidepressants. It should be noted that tricyclic antidepressants, which may be used to treat depression and relieve pain while also leading to a transient increase in norepinephrine, may cause a decrease in norepinephrine turnover and hence be considered sympatholytic. Indications for their use in RSD include treatment of depression, insomnia, and pain per se. A fuller description of their use in depression may be found in Ch§pie.L49.. Tricyclics have been shown to be effective in neuropathic pain, with amitriptyline being the most frequently prescribed agent. The dosages for pain are usually but not always lower (25 to 75 mg) than those for depression (150 mg and higher); their effects are also evident more quickly (days rather than weeks). Even at these lower doses, side effects, including orthostatic hypotension, anticholinergic actions, and electrocardiographic (quinidine-like) abnormalities, make these drugs problematic. The sedative effects of amitriptyline and doxepin may be helpful with regard to sleep. The selective serotonin receptor inhibitors [Zoloft (sertraline hydrochloride), Prozac (fluoxetine hydrochloride), and Paxil (paroxetine hydrochloride)] are easier to use and hence are first-line drugs in the treatment of depression. However, their efficacy in the treatment of pain has not been as well demonstrated as that of the tricyclics. Trazodone (Desyrel), a heterocyclic antidepressant, is advocated by some because of its sedative effects and because it is a potent a-adrenergic blocker. However, it may cause severe gastrointestinal distress, hypotension, and rarely priapism.
F. Corticosteroids. The use of corticosteroids is controversial. Advocates claim that they are especially useful when joint involvement is prominent or bone scans show increased uptake. One protocol consists of 4 days of 60, 40, 30, 20, 15, 10 (in divided doses for the first six doses), and 5 mg. Relapsers may be re-treated with low-dose steroids or a second tapering course with the above doses but with 8 days at each dose. The risks of steroids, particularly the 8-day schedule, must be carefully considered in the light of the paucity of controlled trials regarding their benefit. There have been reports of benefit from regional IV corticosteroids.
G. Miscellaneous. Calcium channel blockers such as nifedipine (10 to 30 mg three times daily) were beneficial in one uncontrolled trial in 7 of 11 patients. Presumably they act by reducing vascular myogenic hyperactivity. Calcitonin has been given, based on the marked degree of osteoporosis in some stages of RSD. Thus, it has been suggested that calcitonin would be particularly useful in the presence of marked bony changes or increased hydroxyproline excretion. Human recombinant calcitonin (0.5 to 1 g daily) is a first-line treatment in many European centers. Some advocates feel that intranasal calcitonin is markedly less effective.
Note: Although oral preparations of local anesthetic agents have been suggested, they are associated with potentially dangerous side effects and cannot be generally recommended.
H. Surgery. Surgery may be required in patients with RSD, but only for carefully defined indications, as there is no such thing as "minor" surgery. These patients have already demonstrated a diathesis for overreaction to injury, and in some cases, it was surgery that led to their RSD. However, under certain circumstances, surgery is indicated. As RSD resolves, it becomes evident that a previously obscured mechanical problem requires surgical correction, or that deformities (requiring capsulotomy, tenolysis) have arisen as a sequela of the RSD. Alternatively, mechanical pain triggers or triggers resulting from nerve injuries, including neuromas and nerve compression, may develop as a sequela of fibrosis and edema and serve to perpetuate the pain cycle. In the case of deformities and mechanical derangements, surgery should be delayed until the RSD is in remission. However, pain triggers will perpetuate RSD and must be addressed as soon as the treatment team is convinced that the RSD has plateaued and further improvement is unlikely to occur unless the pain triggers are addressed.
Surgery should be performed under sympathetic blockade, with particular attention to hemostasis and avoidance of mechanical stress on nerves. Postoperative pain control and elevation are critical, but a tourniquet effect from the overly zealous use of splints and casting should be avoided. Exercises (especially stress-loading exercises) should be started as soon as possible. I. "Refractory" reflex sympathetic dystrophy. Potentially treatable, unrecognized causes of RSD, such as occult infection and triggers, must be identified and addressed. The potential contribution of secondary gain and associated noncompliance, in which the site is purposefully subjected to harmful stressors and even frank self-mutilation may be involved, also must be considered. Although amputation is fortunately rarely necessary and unpredictably useful in refractory cases, all too often it is associated with recurrence of RSD in the stump and poor tolerance of prosthesis or phantom limb pain. Neurosurgical interventions for pain, such as peripheral nerve stimulation and even cord or thalamic stimulation, may be successful.
VIII. Reflex sympathetic dystrophy of the kne< is described in a separate section because until recently it was insufficiently appreciated and rarely considered. It may present as unexpectedly severe knee pain on walking and weight bearing and stiffness and temperature sensitivity following minor injuries (including falls, "sprains," or dashboard injuries). Vasomotor signs may be subtle. There may be relatively little limitation of motion, and gait disturbances are variable. The patellofemoral joint is invariably involved, and tenderness of the medial aspect of patellofemoral joint and medial capsule are characteristic. It has been suggested that severe knee pain and edema without effusions and mechanical allodynia along the margins of the patella and tibial joint lines either with or without a decreased ROM should alert the clinician to this diagnosis.
On the other hand, patients may present with locking and buckling knees because of mechanical derangements resulting from an injury. These may overshadow the RSD that has also resulted from the injury.
It has been suggested that not infrequently surgery or arthroscopy may be performed in cases of unrecognized RSD. This is liable to exacerbate the condition. On the other hand, RSD may be precipitated by knee surgical procedures ranging from arthroscopy to arthroplasty. It may be a common cause of "stiff knee" following arthroplasty. Prolonged pain (mistaken by the unwary for postsurgical pain but usually differentiated from that by the patient) and a poor response to rehabilitation after surgery are suggestive of RSD. Knee infections, meniscal tears, osteochondritiis dissecans, chondromalacia, and neuroma may be considered in the differential diagnosis of RSD or as precipitants of RSD.
This diagnosis must be considered whenever recovery from trauma or surgery is delayed for an unexpectedly long time. As with any type of RSD, the diagnosis is clinical. Increased uptake on the third phase of the bone scan provides corroborative evidence, but this may occur relatively late in the course. Interestingly, other joints in the lower extremities not infrequently show abnormalities. Osteoporosis develops after several weeks. It is diffuse, does not generally involve joint margins, and is often best seen on a skyline view of the patella. MRI is helpful in excluding other conditions. The role of sympathetic blockade in assessment is similar to its role in RSD affecting other locations. Treatment includes the modalities described above. Standing stress therapy and walking with crutches are frequently useful in patients who cannot tolerate other modalities (e.g., active or assisted active ROM exercises). Arthroscopy should be avoided unless it is required for correction of an underlying mechanical disturbance, and it should be delayed until patient is in remission. Arthroscopy, other surgery, or manipulations that may be required if capsular fibrosis occurs should be performed under the protection of sympathetic blockade.
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