Complex Regional Pain Syndrome type 1 (CRPS-1) is a rare, debilitating disease of unknown cause, usually triggered after trauma or surgery. It is characterized by vascular, muscular, skeletal and skin changes – mainly in the extremities.
Type 1 vs Type 2
There are two types of complex regional pain syndrome, with similar signs and symptoms, but with different causes:
Complex Regional Pain Syndrome Type 1. Also known as reflex sympathetic dystrophy, this type manifests itself after an illness or injury that did not directly damage the nerves of the affected limb. Approximately 90% of people with complex regional pain syndrome suffer from type 1.
Complex Regional Pain Syndrome Type 2. This type (formerly known as causalgia) has similar symptoms to those of type 1. However, complex regional pain syndrome type 2 occurs after a specific nerve injury. This injury is usually the result of surgery, trauma, infectious disease (such as shingles) or overuse injury. Type 2 usually affects older people.
Pathophysiology
It is caused by a multifactorial process involving peripheral and central mechanisms. On a scale, these factors contribute differently to each patient, generating diversity in clinical presentations.
- Factors related to the initial injury: Increase of inflammatory cytokines, such as interleukin 1β, substance P, and osteoprotegerin, causing allodynia, hyperalgesia, edema, and vasomotor alteration.
- Nociceptive sensitization central and peripheral: In the central nervous system, there is an increase in neuronal excitability. In the peripheral nervous system, changes occur in afferent fibers that increase the nociceptive discharge for non-painful stimuli such as mechanical and thermal. This explains spontaneous pain, hyperalgesia, and allodynia.
- Altered function of the sympathetic nervous system and sympathetic-afferent coupling: There is an expression of catecholamine receptors in nociceptive fibers; that is, the catecholamines released in response to pain or stress can directly trigger the discharge of nociceptors, generating pain (a phenomenon called sympathetic-afferent coupling).
- Inflammatory and immunological factors: Studies have attempted to associate inflammatory cytokines, immunoglobulin G, and autoantibodies with the genesis of the pathology. The assumption is that CRPS is an expression of autoimmunity.
- Brain changes: Brain imaging studies suggest changes in pain pathways and the somatosensory system.
- Genetic factors: They are still little known. Genes coding for adrenoceptors and the HLA system (human leukocyte antigens) are being researched.
- Psychological factors: Psychological factors alone do not generate CRPS; however, due to pain and disabilities caused by the disease, about 25-49% of patients may develop some mood disorder.
What to Expect from the Disease?
Predicting how complex regional pain syndrome will evolve in a particular patient is difficult, but early diagnosis and treatment have better results.
Many people have relief of symptoms after a few weeks or months of rehabilitation. However, if the symptoms have been present for more than 6 months, it is more likely that the disease will become chronic.
Complex regional pain syndrome usually affects a larger area than the initial injury and can affect the entire limb. Eventually, the symptoms of one limb can also affect the other limb. Symptoms can also return after they have improved.
You should not change your body posture to reduce pain, as this can cause problems in other body parts.
Diagnosis
There is no specific test to confirm the diagnosis. Doctors rely on the symptoms reported by the patient and the physical examination, although some tests may be requested to exclude other diagnoses (such as x-ray, blood tests, and MRI).
Infiltrations can also be used to confirm the diagnosis, but this depends on the doctor’s suspicions at the time of the consultation.
If the pain is throughout the body, not in a specific limb or area, it may be another disease, such as fibromyalgia.
Treatment
There is no one-size-fits-all treatment for all patients, but early mobilization is essential. Typically, treatment involves a combination of rehabilitation (physiotherapy, occupational therapy) and adequate pain management. Furthermore, psychological follow-up usually brings many benefits.
Rehabilitation
Rehabilitation therapies are essential and are more effective the sooner they are started. The main goal is to gain mobility and improve the quality of life. They may not always solve the pain, but they can prevent muscle weakening.
In the beginning, exercises may increase the pain, but it is essential not to be discouraged or give up. If necessary, talk to your doctor to adjust the analgesia for the sessions.
A rehabilitation technique called mirror therapy can help a lot in recovery. The method consists of placing the affected limb in a box and the healthy limb in front of a mirror. The therapy then occurs with the movement of the healthy limb in front of the mirror, which gives the patient the appearance that the affected limb is also moving.
The goal is to provide visual feedback to the patient that he does not feel pain with the limb’s movement. In summary, the technique seeks to trick the brain into forming new neural connections and eliminating pain.
MD, PhD. Physical Medicine & Rehabilitation Physician from São Paulo - Brazil. Pain Fellowship in University of São Paulo.