Complex regional pain syndrome (CRPS) is a neurological disorder characterized by severe and prolonged pain that is disproportionately greater than expected from the original injury or trauma. It is typically accompanied by inflammation and discoloration to the affected area. CRPS has two stages: acute (recent, short-term) and chronic (lasting greater than six months).
CRPS used to be known as reflex sympathetic dystrophy (RSD) and causalgia. The first detailed description of multiple cases of CRPS occurred during the Civil War in the 1860s when thousands of soldiers with traumatic battle wounds and amputations suffered long-term pain after the primary wounds healed. This is where the name causalgia originated.
How does CRPS impact patients?
People with CRPS have spontaneous pain and excessive severe pain, sometimes following something as mild as a light touch. Other symptoms include variations in skin color, temperature, and/or swelling on the arm or leg below the site of injury.
Although CRPS may improve over time and may resolve completely, other people may have severe or prolonged cases that are profoundly disabling. Unmanaged CRPS can also spread from one limb to another
What causes CRPS?
The inciting injury for CRPS may be as simple as a sprain or strain, but more typically follows fractures, surgery or other severe trauma to a limb.
Most CRPS cases are caused by damage to and improper function of the peripheral C-fiber nerve fibers that carry pain messages to the brain. Their excess firing also triggers inflammation designed to promote healing, but in CRPS the inflammation becomes chronic and detrimental. In people with severe trauma, the nerve injury is usually obvious, but in others, a specialist may be needed to locate and treat the injury.
CRPS-I and CRPS-II
Historically, people were classified as having CRPS-I (previously called RSD) when there was uncertainty about the exact nerve injured.
If a doctor identifies the specific nerve injured, people are then diagnosed as having CRPS-II (previously known as causalgia). Many people labeled with CRPS-II have more extensive initial injuries with corresponding damage to nerves leading to muscles (motor nerves). This causes weakness and muscle shrinkage in certain areas, making the diagnosis easier.
Since both types of CRPS have identical symptoms, both may be caused by nerve injury, although nerve injuries in CPRS-I are typically more subtle and more difficult to diagnose.
CRPS is at least three times more common in women than in men, but can occur in anyone at varying stages of life. It is rare in the elderly, who have less inflammation after injury, and in young children who heal more quickly and completely.
What’s the outcome of CRPS?
Early diagnosis and treatment by a qualified doctor are very important. The prognosis of CRPS improves significantly when the condition is diagnosed in the acute phase, within 6 months of onset. This also greatly reduces the chance of the condition spreading to other areas of the body.
Some CRPS conditions are relatively mild and individuals recover, a process that can take anywhere from a few months to a few years as the injured nerve regrows. If this doesn’t happen, symptoms can linger to cause long-term disability.
The outcome depends not only on the severity of the original injury but also on the person’s underlying general and nerve health. Younger people, children, and teenagers are more likely to recover, as do older adults with good circulation and nutrition.
Smoking is a major impediment to nerve regeneration as is diabetes and previous chemotherapy. Removing barriers to healing increases the chance and speed of recovery.
Some individuals experience prolonged severe pain and disability despite treatment. This may indicate underlying separate problems interfering with healing requiring additional testing and treatment.
Because of the varied symptoms, the fact that symptoms may change over time, and the difficulty finding a positive cause in some cases, CRPS is hard to treat. There is no single therapy that rapidly reduces symptoms or cures CRPS. Instead, treatment needs to be multi-dimensional and holistic, and in addition to drug treatments, should include physical therapy and counseling by qualified practitioners experienced in CRPS.