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Available or current treatment guidelines

Awareness of complex regional pain syndrome (CRPS) by general practicing physicians is poor, which often leads to delays in treatment. Rehabilitative therapies coupled with pharmacotherapy are the mainstays of early treatment. Interventional treatments are considered if conservative strategies fail.1 There are no well-accepted treatment guidelines for pharmacotherapy.1 Best evidence supports multidisciplinary care.

Traditional Treatments

1. Physical therapy and occupational therapy

Physical therapy (PT) and Occupational therapy (OT) can improve outcomes in CRPS, when started early (symptoms for less than 1 year).3Objectives of PT and OT in CRPS are to improve range of motion, desensitization, minimize swelling, promote normal positioning, decrease muscle guarding, and increase functional use of the extremity.4

2. Mirror box therapy

Mirror box therapy may improve affected limb range of motion (ROM) by cortical reorganization of pain and motor neural networks.5

3. Graded motor imagery

Graded motor imagery (GMI) treatment is focused on training the brain to re-connect to the body part affected by pain. When you have CRPS in one part of your body, your brain recognizes the extremity affected as a painful threat. There are 4 steps to GMI, and these include laterality, imagery, sensory discrimination, and mirror therapy. GMI has been shown to improve altered central processing in CRPS, which may improve symptoms.6

4. Tactile (or sensory) discrimination training

Tactile (or sensory) discrimination training has been shown to help pain and function in CRPS.7 By teaching the body part and the associated area of the brain how to differentiate between various sensations it helps clear the picture in the brain.

5. Transcutaneous nerve stimulation (TENS)

There is limited evidence supporting efficacy CRPS type 1 (CRPS1). Most articles demonstrate flawed methodology, or sample size resulting in insufficient evidence that TENS is effective.7

6. Cognitive Behavioral Therapies

Regardless of the duration of the condition, all CRPS patients and their families should receive education about the negative effects of disuse, the pathophysiology of the syndrome, and possible interactions with psychological/behavioral factors. All patients with chronic CRPS should receive a thorough psychological evaluation, followed by cognitive-behavioral pain management treatment, including relaxation training with biofeedback, reframing, hypnosis, and behavioral modifications.8

Non-traditional Treatments

1. Complementary therapies

Isolated case studies show a potential role for acupressure and acupuncture. Herbal medicines, anti-inflammatory type diets, and natural supplementation have also found roles in treatment for CRPS.5

2. Hyperbaric oxygen

Hyperbaric oxygen therapy may be considered, which may lead to potential improvement in range of motion, pain control, and edema management.5

3. Electroconvulsive therapy

There are case reports of secondary improvement in CRPS symptoms when electroconvulsive therapy is used for depression.5

Pharmacologic therapies

1. Nonsteroidal anti-inflammatory agents

Clinical trials have shown mixed results, questioning their benefit in CRPS.7

2. Antiepileptic drugs

Gabapentin may improve pain and sensory deficits. Newer options include pregabalin and topiramate. Older options include carbamazepine.7

3. Bisphosphonates

Bisphosphonates may be beneficial through several different mechanisms. They can reduce osteoclastic activity and modify inflammatory cytokines. Studies with alendronate have shown significant improvement in pain and motion.5

4. Calcitonin

Calcitonin may be beneficial via increasing intracellular Ca within the dorsal horns, which may enhance calcitonin gene related peptide which aids in antinociception and delayed bone loss.5

5. Corticosteroids

Prednisone dosing 30 mg/d for a period of 2 to 12 weeks, (including a tapering period) may provide significant pain and functional improvement in early stage CRPS .5

6. Phenoxybenzamine

Oral phenoxybenzamine is an alpha-1 antagonist that has shown benefit in CRPS. The dose is slowly increased up to a maximum daily dose in the range of 40 to 120 mg, with treatment duration of 6 to 8 weeks. Orthostatic hypotension and ejaculatory problems can be expected at the higher dose range.5

7. Nifedipine

Limited data may indicate that the calcium channel blocker, nifedipine, may be helpful at daily doses of up to 60 mg.5

8. Opioids

There is a lack of evidence to support long term (>6 months) opioids in CRPS. While tramadol may be of benefit in neuropathic pain, there is, again, little scientific support in CRPS.7

9. Ketamine

NMDA receptor and hyperpolarization activated cyclic nucleotide gated potassium channel 1 receptor antagonist that also has dopaminergic effects which may produce improvement in pain. However, literature does not demonstrate significant functional improvement.5

10. Antidepressants

While commonly used in neuropathic and chronic pain conditions, there is little specific evidence of their benefits in CRPS.7

11. Disease modifying antirheumatic drugs

Tissue necrosis factor-alpha inhibitors9 are limited to moderate evidence, but may serve as a potential treatment plan in CRPS.

12 Topical agents

  1. Capsaicin
    Long-term topical capsaicin application can reduce epidermal C fiber density with resultant decreased substance P production. There are clinical strengths ranging from 0.025% to 0.15%, but this has been poorly tolerated in CRPS because of inherent burning sensation when applied despite concentrations administered.5
  2. Transdermal lidocaine
    Compared with capsaicin, transdermal lidocaine may be better tolerated. Few cases in the literature demonstrate long term improvement of pain.7
  3. Isosorbide dinitrate
    Vasodilator, for which there has been only a small study in the CRPS1 population, but not CRPS2. The study showed some improvement in mean skin temperature if the CRPS1 was of the “cold” type.5
  4. Topical clonidine
    Clonidine is an alpha-2 adrenergic agonist, and topical administration may help local CRPS induced allodynia and hyperalgesia.5
  5. Topical diclofenac
    Diclofenac is a non-steroidal anti-inflammatory drug, and it may serve as an effective treatment option for patients with neuropathic pain from CRPS.11

12. Intravenous immunoglobulin (IVIG)

IVIG can interfere with proinflammatory markers and cytokines. Small studies of low dose IVIG have shown some benefit in chronic pain syndromes and CRPS.12

13. Therapeutic Plasma Exchange

Considering the evidence of immune system involvement in CRPS, plasma exchange showed to be effective in a subset of patients with long standing CRPS. Plasma exchange is hypothesized to reduce a number of factors that contribute to neuropathic pain such as inflammatory cytokines and fibrinogen, and it can also increase serum anti-inflammatory cytokines.13

Interventional therapies

1. Sympathetic block

Sympathetic blocks have been used for both diagnostic and therapeutic purposes in CRPS. Sympathetic block is generally considered the first choice when interventional treatments are considered. Stellate ganglion blocks are indicated for upper-extremity CRPS, and lumbar sympathetic blocks are indicated for lower-extremity CRPS. Despite extensive historical use in the treatment of CRPS, a critical review of the literature reveals poor quality and limited/moderate evidence. Problems include lack of control populations, small sample sizes, retrospective protocols, and inadequate evaluation of symptom responses.

Sympathetic blocks are generally more likely to help if skin discoloration and temperature changes are present. A series of injections is usually prescribed; however, there is no convincing evidence to conclude that a series of sympathetic blocks is indicated unless there is progressive improvement of symptoms with each injection.5

2. Radiofrequency sympathectomy

Considered when sympathetic blocks provide short-term relief.5

3. Intravenous regional blocks

Administration of Intravenous (IV) medication after exanguination of a limb followed by tourniquet placement. Guanethidine, reserpine, droperidol, or atropine has not been shown to be effective. However, regional blockades with bretylium or ketanserine can result in significant pain reduction.7

4. Spinal cord stimulation

Spinal cord stimulation directly stimulates the dorsal columns to modulate neuropathic pain. Good evidence to support spinal cord stimulation durability for long term pain and quality of life improvement. Limited evidence supporting functional improvement.14

5. Dorsal Root Ganglion stimulation

Spinal cord stimulation (SCS) is an effective intervention for CRPS, but is hampered by the technical challenges associated with precisely directing stimulation to distal extremities. Dorsal root ganglia (DRG) may be more effective as a physiological target for electrical modulation due to recruitment of the primary sensory neurons that innervate the painful distal anatomical regions.

6. Implantable intrathecal continuous infusion pump

  1. Opioid Infusion:
    Studies specific to CRPS are lacking with implantable continuous infusion pumps with opioid therapy and use is generally not recommended in CRPS. It has been considered; however, only in specific patients with very poor pain control, hypersensitivity, and markedly decreased range of motion. In rare cases, it should be combined with aggressive physical therapy to improve mobilization.5
  2. Clonidine and Adenosine Infusion:
    Preclinical data suggest that intrathecal clonidine and adenosine reduce hypersensitivity. The prevalence of sensory gain and loss on testing in patients with neuropathic pain varies as a function of presumed etiology, with hyperalgesia being most common in CRPS. Both intrathecal clonidine and adenosine acutely inhibit experimentally induced and clinical hypersensitivity in patients with chronic regional pain syndrome.14

7. Intrathecal baclofen therapy

A few studies have shown that intrathecal baclofen therapy may be of benefit in CRPS1 patients, particularly those with dystonia.7

Surgical interventions

1. Amputation

Several retrospective studies of CRPS1 (but not CRPS2) patients indicate that approximately half had pain improvement after amputation. However, a significant amount had relapses with stump or phantom limb pain.7

2. Surgical sympathectomy

If there is excellent but temporary improvement from sympathetic blockade on repeated occasions, then surgical sympathectomy may be of benefit. Its chance of success is best if performed within the first 3 months after the initial trauma. Relief of pain may decline with time.5

3. Motor cortex stimulation

Recent case reports illustrate the use of motor cortex stimulation in CRPS. A craniotomy is performed and placement of an extradural grid is optimized using somatic evoked responses to cover the areas of pain. The mechanism of action probably involves spinal cord structures including spinal sympathetic nucleus and ventral roots.

4. Deep brain stimulation

DBS is the most invasive form of neuromodulation. Specifically, it involves targeting a deep structure in the brain. DBS targets CNS structures; if such structures are injured/maladaptive, suboptimal inhibition may be evident.

Treatment conclusions

Treatment for CRPS can be difficult and frustrating. Each patient will be different, and an individualized approach is essential. Aggressive early treatment should be emphasized through an interdisciplinary approach. Most treatments are not well-documented in the evidence-based literature. Early physical and occupational therapy is important. Sympathetic blockade can be considered as the first interventional technique. Medication management to include corticosteroids and bisphosphonates are best supported in the literature. Other adjuvant medication can be considered, as previously described. Different pharmaceutic interventions can then be attempted to try to improve symptoms.

Emerging/unique Interventions

Prognosis is best with early diagnosis and treatment. Once delayed, CRPS can spread proximally in the affected limb and to other areas of the body. Significant loss of function, atrophy, and contractures can result. Nonorganic factors may worsen CRPS. As such, psychologic therapy can be an important component, and may include cognitive behavioral therapy.


Cutting edge concepts and practice

An inflammatory immune response can be activated in CRPS. IVIG can affect proinflammatory markers and cytokines and is an encouraging treatment for CRPS. Randomized controlled studies in refractory CRPS have shown benefit.5 Even in a variety of chronic pain syndromes, open label studies using low-dose IVIG have been effective in pain reduction. However, these studies are small, and there are valid concerns about the cost and availability of such treatments.5

In regards to the inflammatory response of CRPS, dexmedetomidine is a selective α2-adrenoceptor agonist, and it might alleviate allodynia through GRK2 upregulation in sympathetic postganglionic neurons.15

Memantine is a drug with the ability to block NMDA receptors in the brain and a potent inhibitor of central and peripheral sensitization. Some studies suggest that it may be a promising option for the treatment of CRPS.16

Microvascular dysfunction and ischemia in muscle play a role in the development of cutaneous tactile allodynia in chronic post-ischemia pain. Pentoxifylline, a vasodilator and haemorrheologic agent may be beneficial if used early in treating CRPS related to chronic post-ischemia pain.16

Bisphosphonates, which have a potent inhibitory effect on bone resorption, were proposed for the treatment of CRPS. In fact, several studies indicated that the intravenous or high-dose oral administration of bisphosphonate improved pain and reduced bone turnover in CRPS cases. Administration of low dose of oral risedronate (2.5 mg per day) or alendronate (35 mg per week) markedly decreased pain and regional osteoporotic findings in the foot or ankle.


Gaps in the evidence-based knowledge

There is controversy over the accepted pathophysiology of the disorder. Initially, CRPS was thought to be predominantly mediated through the sympathetic nervous system; however, autonomic symptoms are often not seen on clinical presentation. Moreover, some CRPS patients do not get relief from sympathetic blockade and plasma catecholamine levels are generally lower in the affected limb.

Other mechanisms thought to be involved include cortical reorganization, exaggerated inflammatory response, and neurogenic inflammation primarily through neuropeptide mediators including bradykinin, calcitonin gene-related peptide, and substance P.5

A major gap in the evidence is the paucity of double-blinded placebo-controlled clinical trials. For a variety of reasons, CRPS patients are commonly excluded from pharmaceutic studies.


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Original Version of the Topic:

Stephen Kishner, MD. Complex regional pain syndrome Part 2: Management and Treatment. Publication Date: 2012/07/25.

Author Disclosure

Stephen Kishner, MD
Nothing to Disclose

Brandon L Hicks, MD
Nothing to Disclose