What is Complex Regional Pain Syndrome?

Complex regional pain syndrome explained by Denver, Golden, Aurora, Boulder, Broomfield, Jefferson, and Littleton Colorado’s top pain doctors

Complex Regional Pain SyndromeChronic pain in the upper and lower limbs is known as complex regional pain syndrome. This syndrome usually develops due to an injury or illness that disrupts the normal function of the peripheral and central nervous systems. Complex regional pain syndrome can be associated with loss of motor and sensory function. The pain experienced by patients with this syndrome is significantly more extreme than the severity of the injury or circumstance that caused it. The symptoms are localized in one region of the body; however, they may gradually progress to other body regions.

Complex regional pain syndrome patients may experience swelling, variations in skin color, sensitivity to touch or cold, changes in hair and nail growth and/or changes in the temperature of the skin that are characterized by alternating between feeling cold and sweating. Patients may experience persistent burning or throbbing pain that usually is from the peripheral nervous system. There is often joint stiffness, muscle spasms, muscle weakness associated with atrophy, or decreased ability to move the affected region of the body.

The onset of the syndrome is often characterized by painful swelling and redness, in addition to obvious changes in skin temperature and sensitivity to touch or cold. Emotional stress can exacerbate these symptoms. Complex regional pain syndrome may result in irreversible damage. A decrease in skin color (skin appears pale), cold skin temperature, muscle spasms, and muscle tightening are indications that the condition has become irreversible.

Causes of Complex Regional Pain Syndrome

Complex Regional Pain Syndrome ComparisonComplex medical conditions such as a heart attack, stroke, serious injury (e.g., spinal injury), or complications from a surgery are thought to be associated with the development of complex regional pain syndrome. These conditions can induce severe nerve inflammation and injury, resulting in high levels of pain that are not consistent with the severity of the underlying injury or condition.

The peripheral and the central nervous systems are thought to be associated with complex regional pain. Damage to the small nerve fibers of the peripheral nervous system that transmit information regulating the function of blood vessels can cause those fibers to become overactive. This can cause inflammation of the nerve and cause the blood vessel to undergo dilation, constriction, or to leak fluid into the surrounding tissue. Dysfunction of or damage to blood vessels within an affected limb may also lead to symptoms. Muscles surrounding the affected blood vessels may be deprived of sufficient oxygen which could damage the muscle and cause pain in the muscle and joint.

Most cases of complex region pain syndrome are associated with a condition or trauma that may have caused the symptoms. Fractures, sprains/strains, injuries to soft tissue (e.g., bruises or cuts), immobilization of a limb, or an injury resulting from surgery or other medical procedures are the most common conditions associated with complex regional pain syndrome. Cases of complex regional pain syndrome occurring in the absence of any trauma or injury are quite rare. However, some cases do not have an identifiable injury or trauma. These cases are probably associated with an undiagnosed underlying condition, such as an infection, blood vessel problem, or nerve entrapment. A few studies suggest that complex regional pain syndrome has a genetic component. However, there are very few reports of complex regional pain syndrome occurring among members of the same family.

Treatments for Complex Regional Pain Syndrome

Physical therapy may alleviate the early symptoms of complex regional pain syndrome, such as poor circulation, inflexibility, muscle stiffness, and loss of muscle. Physical therapy early in the course of the syndrome may allow patients to avoid or even reverse some of the secondary changes in the brain associated with the progression of chronic pain.

No medications have been approved for the treatment of complex regional pain. However, several drugs can provide patients some relief from their symptoms. Non-steroidal anti-inflammatory drugs (NSAIDs) are often administered to patients experiencing moderate pain. These medications are effective because they reduce inflammation in the affected area. In addition, oral corticosteroids, such as prednisone and cortisone, can reduce pain and inflammation in the affected regions. There are a few drugs originally developed to treat depression that are also effective for the relief of neuropathic pain.

Spinal Cord Stimulator - XRAYThe application of spinal cord stimulation may also provide patients with a reduction in their level of pain. A device implanted near the spinal column emits electrical impulses that disturb the transmission of pain signals from the nerves within the spine. Intrathecal pump implants that pump pain-relieving medications directly to the area surrounding the spinal cord can also provide patients with pain relief. Some patients may benefit from biofeedback training to manage their symptoms of pain. The patients are taught relaxation skills and coping skills that allow them to achieve some control over their pain symptoms. Techniques, such as acupuncture, may also provide some patients with relief from the symptoms associated with complex regional pain syndrome.


Complex regional pain syndrome causes chronic and severe pain in the limbs. The condition is caused by a disruption of the function of the peripheral and central nervous systems. Most of the patients that develop complex regional pain have a history of injury or trauma that can be linked with the onset of symptoms; however, some cases show no identifiable cause. There are a variety of effective treatments for managing the symptoms of complex regional pain syndrome. Patients should consult their physician in order to determine the appropriate treatment plan.

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