Complex regional pain syndrome - 1

Complex Regional Pain Syndrome (CRPS), often post-injury, involves sensory, autonomic, and motor symptoms. Treatment, ideally multidisciplinary and early, includes physical therapy, medication like NSAIDs or gabapentin, and bisphosphonates for specific cases. Refractory CRPS may require interventional pain management. Prognosis varies, with potential recurrences preventable by vitamin C.

Overview

Complex regional pain syndrome (CRPS) is a serious continuing neurological painful condition which may follow a bony fracture, soft tissue injury, or surgery. Occasionally the problem could develop after a shoulder trauma, or myocardial infarction. CRPS has two subtypes. CRPS type I happens without evidence of peripheral nerve damage and represents about 90% of cases. The disorder usually affects distal parts of the limb (mostly the upper limb). The disorder is characterized by sensory, autonomic, trophic and motor problems. Sensory problems include a burning spontaneous pain. The pain worsens in dependent position of the limb. Autonomic abnormalities include swelling and change of sweating in the limb, which is usually warmer than the other limb. Trophic changes include abnormal nail growth, and/or increased or decreased hair growth in long term cases. Motor symptoms include weakness of muscles of the affected part. Bone scintigraphy could help tom distinguish CRPS if it shows an ipsilateral higher radioactive uptake in joints distant from the site of trauma. (1, 2, 3)

Treatment Goals and Approach

The goals of treatment are to restore the function of the limb for patients, and increase their quality of life. Treatment has to be initiated soon after diagnosis for better outcomes. A multidisciplinary approach is required. This includes neurology specialist, physical therapist, pain specialist, occupational therapy specialist and psychiatry specialist. Treatment includes both non- pharmacological measures and pharmacological modalities. (4)

Non-Pharmacological Measures

Non- pharmacological measures represent first line treatment and include patient education, physical therapy (PT), and occupational therapy (OT). They include general exercises and strengthening, gait retraining, transcutaneous electrical nerve stimulation (TENS), pacing, prioritizing, and planning activities, relaxation techniques, graded motor imagery, and graded pain exposure to reduce pain avoidance behavior. (5)

Pharmacological Treatment

Medical therapy includes nonsteroidal antiinflammatory drugs (NSAIDS), such as, ibuprofen (400 mg two to three times daily) or naproxen (250- 500 mg twice daily). Also, adjuvant medications for neuropathic pain with gabapentin (starting at 300 mg daily or 100 mg for older adults), or pregabalin (50-75mg daily) may be useful for pain management. Furthermore, certain antidepressant medications, including amitriptyline (starting at 10 mg daily), can be effective in reducing neuropathic pain. Furthermore, bisphosphonate therapy could benefit those patients with abnormal radioactive uptake. Agents include oral alendronate (at a dose of 40 mg daily for eight weeks), or intravenous clodronate (300 mg for 10 days). Adverse effects of bisphosphonates include transient hypocalcemia, flu-like symptoms, musculoskeletal pain, renal toxicity, and jaw necrosis. Moreover, low does opioids (oxynorm 5 mg three times daily as needed) could help the patients, although, there is a paucity of high-quality data supporting their efficacy for CRPS. The duration of therapy is individualized. For all medications except bisphosphonates (which are given as a discrete course), therapy is generally continued as long as the patient has significant symptom burden, and side effects are tolerable. Once symptoms improve, medications could be gradually tapered. (6, 7)

Refractory Cases and Interventions

Patients with refractory disorder should be referred to a pain management specialist. Interventional procedures include regional sympathetic nerve block with lidocaine, cord stimulation, epidural clonidine, trigger/ tender point injections, and chemical sympathectomy. (8)

Prognosis and Prevention

The prognosis of CRPS is unpredictable. While some patients have some degree of disability, almost (20- 30% of patients) showed good recovery. Also, recurrences could occur and could be linked to new trauma or surgical intervention. For prevention of CRPS, vitamin C (500mg daily) is helpful for patients with distal radial fractures or after foot or ankle surgeries. However, the results of vitamin C in clinical trials are unclear. (9, 10)

References

1- Wasner G, Heckmann K, Maier C, Baron R. Vascular abnormalities in acute re¯ex sympathetic dystrophy (CRPS I): complete inhibition of sympathetic nerve activity with recovery. Arch Neurol 1999; 56: 613 ± 620.

2-Petersen P.B., Mikkelsen K.L., Lauritzen J.B., Krogsgaard M.R. Risk factors for post-treatment complex regional pain syndrome (CRPS): an analysis of 647 cases of CRPS from the Danish Patient Compensation Association. Pain Pract. 2018;18:341–349.

3-Wertli M.M., Brunner F., Steurer J., Held U. Usefulness of bone scintigraphy for the diagnosis of Complex Regional Pain Syndrome 1: a systematic review and Bayesian meta-analysis. PLoS One. 2017;12

4-Avdic D., Jaganjac A., Katana B., Bojicic S., Hadziomerovic A.M., Svraka E. Complex regional pain syndrome (CRPS) J Health Sci. 2015;5:1–4.

5-Smart K.M., Wand B.M., O'Connell N.E. Physiotherapy for pain and disability in adults with complex regional pain syndrome (CRPS) types I and II. Cochrane Database Syst Rev. 2016;2:CD010853.

6-Dworkin R.H., O’Connor A.B., Backonja M. Pharmacologic management of neuropathic pain: evidence-based recommendations. Pain. 2007;132:237– 251.

7-Perez R.S., Zollinger P.E., Dijkstra P.U. Evidence based guidelines for complex regional pain syndrome type 1. BMC Neurol. 2010;10:20.

8-O'Connell N.E., Wand B.M., McAuley J., Marston L., Moseley G.L. Interventions for treating pain and disability in adults with complex regional pain syndrome. Cochrane Database Syst Rev. 2013:CD009416.

9-Shah RV, Day MR. Recurrence and spread of complex regional pain syndrome caused by remote-site surgery: a case report. Am J Orthop (Belle Mead NJ) 2006; 35:523.

10-Ekrol I., Duckworth A.D., Ralston S.H., Court-Brown C.M., McQueen M.M. The influence of vitamin C on the outcome of distal radial fractures: a double-blind, randomized controlled trial. J Bone Jt Surg Am. 2014;96:1451–1459.