Complex regional pain syndrome

Dr. Sheila Espinal, Rehabilitation Medicine, Coordinator of the Department of Physical Medicine and Rehabilitation.

Complex regional painful syndrome (CRPS) is a chronic condition characterized by severe pain in the extremities, associated with a nerve injury or minor trauma.

This entity has been known by different names, among them: causalgia, Sudeck syndrome, cotton wool, shoulder-hand syndrome, reflex sympathetic dystrophy and complex regional painful syndrome (CRPS), the latter being the term established in 2001 by Schott, and the which is considered more reliable in relation to symptoms.

The annual incidence varies between 5 to 26 cases per 100,000 people and is 3 to 4 times more frequent in women. CRPS is often associated with surgery and minor trauma.

Symptom. Among the most frequent presented are:
• Temperature changes in the limb (heat or cold) that may vary suddenly.
• Changes in the texture and color of the skin, presenting a reddened, shiny and / or scaling skin.
• Pain and edema of the limb.
• Hypersensitivity to superficial friction.
• Rigidity that produces functional limitation of the joints involved.

Pain and limitation for movements are usually the reasons for consulting this condition that is characterized because spontaneous or induced pain is usually disproportionate in relation to the initial event, and is accompanied by alterations of the autonomic nervous system, which results in Wide variety of clinical presentations.

Causes. The causes of CRPS are not fully established, but three theories have been postulated as triggers:
1. Post-traumatic inflammation: This theory expresses that after trauma proinflammatory substances are released (such as the peptide related to the calcitonin gene, substance P, tumor necrosis factor and lainterleukin 6) that are associated with increased hyperexcitability Neural, edema and color changes

2. Peripheral vasomotor dysfunction: This postulate explains the temperature modification in the affected limb that we observe in patients. There are three possibilities of clinical presentation: hot, intermediate and cold limb. This, as a result of an alteration in the constriction function of the arteries and veins.

3. Functional changes of the central nervous system: it establishes that at the level of the peripheral and central nervous system there is an altered sensitization process, explained by the blockage of the inhibitory pathways and by the hyperexcitability of the excitatory pathways, which causes distortion of the sensory and painful stimuli, so a mild stimulus, such as rubbing clothes, can be interpreted as painful.

Two types of complex regional painful syndrome have been defined

• SDRC type 1: It represents 85% of cases and it is not possible to identify a nerve injury as the origin of the signs and symptoms.

The following have been proposed as potential risk factors for developing type 1 CRPS:
- Be female, especially if you are in the postmenopausal stage
- Suffer an ankle sprain or its intra-articular fracture.
- Immobilization
- Severe pain present in the early stage of trauma.

• SDRC type 2: In this type of syndrome, a nerve injury is identified.

Diagnosis. The diagnosis of complex regional painful syndrome is primarily clinical. To do this, characteristics, known as the Budapest criteria, are taken into account. The patient must have at least one symptom and a sign of the following:

1. Pain continued disproportionate in relation to the triggering event.

2. The patient must report at least three symptoms of the following:
A. Sensory: sensation of cramps, numbness, heaviness, or pain with superficial rubbing.
B. Vasomotor: changes in color or temperature compared to the other limb.
C. Sudomotor: edema or excessive sweating compared to the contralateral limb.
D. Motor / trophic: report of the decrease in range of motion, weakness, tremor or trophic changes (excessive growth in hair, nails and dry skin).

3. At the time of the evaluation, you must show at least one of the following signs:
A. Sensory: evidence of hypersensitivity or pain to soft touch, deep pressure or joint movement.
B. Vasomotor: evidence of temperature asymmetry or skin color changes compared to the contralateral limb.
C. Sudomotor: edema or asymmetric sweating.
D. Motor / trophic: decreased range of motion, weakness, tremor or changes such as abnormal growth of hair, nails, or dryness and peeling of the skin.

4. That there are no other diagnoses that explain the signs and symptoms.

Prevention. Prevention will be the preferable option to any health condition, and the case of complex regional pain syndrome is no exception. The CRPS can be prevented by taking into account the following variables:

• Ingest vitamin C after a wrist fracture. Studies have shown that people who took a minimum daily dose between 500–1000 milligrams of vitamin C for at least 45 days after a wrist fracture had a lower risk of developing CRPS compared to those who did not take vitamin C. These Results are valid only for prevention after wrist fracture, current evidence does not indicate risk modification in fractures that occur in other joints.

• Early mobilization after a stroke. It is well known that the immobilization time contributes to the presentation of complex regional painful syndrome, this is applicable to cerebrovascular events, commonly known as thrombosis. Some research suggests that those who receive timely physical therapy during hospitalization reduce the risk of developing CRPS.

1- Can complementary studies be carried out to diagnose complex regional painful syndrome?
Yes, although it is a clinical diagnostic syndrome, cabinet studies can be performed at different stages of the complex regional painful syndrome to support the clinical presumption; The indication depends on the specific presentation. When we want to assess vasomotor changes we can use vascular doppler. Bone densitometry and skin biopsy are useful for measuring atrophy and decreased nerve density. Electrodiagnostic tests allow the evaluation of the peripheral nervous system that supports the type 2 CRPS that is associated with nerve injury. Magnetic resonance imaging assesses soft tissue injuries and bone edema.

2 With what other pathology can complex regional painful syndrome be confused?
There are several clinical entities that should be considered when we consider the diagnosis of this syndrome in which they are: infectious arthritis, rheumatic arthritis, inflammatory arthropathy and peripheral arteriopathy.

Posted in: Hoy Digital newspaper.