Complex Regional Pain Syndrome (CRPS)

Key Points

1. CRPS is a complex pain condition that could result in significant functional disability and psychological stress.

2. It is thought to be a combination of mechanisms that explain the symptoms of CRPS.

3. Each person has different manifestation of CPRS and response to treatment differently.

4. There are multiple treatment options available for CRPS. It is important to have a comprehensive targeted treatment plan.

5. Early intervention and rehabilitation is essential for CRPS prognosis.

What is CRPS?

Complex Regional Pain Syndrome (CRPS)  is a pain condition of a person’s body part (such as arm, hand, leg or foot), after a traumatic injury (which could be minor). CRPS has been known as reflex sympathetic dystrophy syndrome (RSDS), algodystrophy, causalgia, shoulder-hand syndrome, Sudeck’s atrophy and transient osteoporosis. There are two types of CRPS, Type I (with NO nerve damage present) and Type II (with nerve abnormality detected).

What causes CRPS?

There is no known single cause of CRPS. It is thought to be a combination of different factors that take place at the time injury. Each of the following factors contribute differently for each person in different ways and one person’s response to treatment will be different from another person’s. 

The mechanism of CRPS include

1. Excessive inflammation changes

2. Immunological changes

3. Overly sensitised nervous system

4. Autonomic dysfunction

5. Central reorganisation

6. Psychosocial influences

7. Genetic predisposition.

The combination of the mechanism above could result in:

1. Acute inflammatory changes with swelling, redness, heat, pain

2. Reduced bone density (osteopenia)

3. Distorted body representation

4. Psychological symptoms, such as fear avoidance, limb alienation, anxiety, depression

5. Overly protective nervous system with spontaneous pain, excessive pain, sensitive to light touch or wind

6. Autonomic dysfunction with asymmetrical colour changes, temperature changes and increased sweating

7. Dystonia

Smoking is a risk factor for the condition. Females are 3 times more likely to be affected. In adults, the most commonly affected limb is the arm. In children, it is the leg. 

Treatment Options

There is no simple solution for CRPS. Treatments involves approaches and aims to restore movement and function of the affected limb. 

1. Multidisciplinary pain management approach with physical therapy, occupational therapy and psychological therapy. This includes addressing the psychological barriers, retraining of function, graded motor imagery or mirror box therapy.

2. Early use of anti-inflammatories, such as corticosteroids

3. Early intervention for radiological-evidence of osteopenia with Bisphosphonates or DMSO cream

4. Use of anti-neuropathic medications, with options of oral, topical or intravenous medications

5. Minimally invasive procedures such as sympathetic nerve blocks, radiofrequency treatments, botox injection

6. Neuromodulation

Prognosis

Most people recover from CRPS, but for some there is ongoing symptoms with significant pain and disability for years. Some develop another episode of CRPS after symptoms free for some times. There are some evidence on using Vitamin C to prevent CRPS in the event of wrist, foot and ankle injuries. Smoking cessation may play a role in preventing the condition from developing. 

Early identification, Early intervention, Early Rehabilitation are the keys for better prognosis. 

Reference:

1. Shim H, Rose J, Halle S, Shekane P. Complex regional pain syndrome: a narrative review for the practising clinician. Br J Anaesth. 2019;123(2):e424-e433. doi:10.1016/j.bja.2019.03.030

2. Complex regional pain syndrome (CRPS). Better Health Channel Victoria. https://www.betterhealth.vic.gov.au/health/ConditionsAndTreatments/complex-regional-pain-syndrome-crps. Accessed on 12 Apr 2021.

3. Complex Regional Pain Syndrome (CRPS). Harvard Health Publishing. Harvard Medical School. https://www.health.harvard.edu/a_to_z/complex-regional-pain-syndrome-crps-a-to-z. Accessed on 12 Apr 2021.

4. Greta Palmer. Complex regional pain syndrome. Aust Prescr 2015;38:82-6. DOI: 10.18773/austprescr.2015.029