Although complex regional pain syndrome (CRPS) has been a recognised medical condition for more than 150 years, The exact mechanism of how RSD develops is poorly understood.
Complex regional pain syndrome occurs in two types, with similar signs and symptoms, but different causes:
Type 1. Also known as reflex sympathetic dystrophy syndrome, this type occurs after an illness or injury that didn't directly damage the nerves in your affected limb. About 90 percent of people with complex regional pain syndrome have type 1.
Type 2. Once referred to as causalgia, this type follows a distinct nerve injury.
A variety of events can trigger the RSD, including:
- Heart disease,
- Degenerative arthritis of the neck,
- Stroke or other brain diseases,
- Nerve irritation by entrapment (such as carpal tunnel syndrome),
- Shoulder problems,
- Breast cancer,
- Drugs for tuberculosis and barbiturates.
There's no single test for complex regional pain syndrome (CRPS). It's usually diagnosed by ruling out other conditions that have similar symptoms.
The following procedures may provide important clues to diagnose RDS.
Physical exam and your medical history.
Bone scan. This procedure may help detect bone changes. A radioactive substance injected into one of your veins permits viewing of your bones with a special camera.
Sympathetic nervous system tests. These tests look for disturbances in your sympathetic nervous system. For example, thermography measures the skin temperature and blood flow of your affected and unaffected limbs.
Other tests can measure the amount of sweat on both limbs. Dissimilar results can indicate complex regional pain syndrome.
X-rays. Loss of minerals from your bones may show up on an X-ray in later stages of the disease.