Complex regional pain syndrome (CRPS) is a chronic pain condition that affects the arms and legs. The main cause is generally trauma or an accident of some kind, but not necessarily directly in the area affected by CRPS. This condition is as complex as its name, and treatments can vary widely in both practice and efficacy.

The body has two main nervous systems, the central nervous system and the peripheral nervous system. The central nervous system is mission control and consists of the brain and spinal cord. The peripheral nervous system includes all of the other nerves that spread out across and through the body, including the organs, skin, and limbs. When either of these systems sustain a prolonged trauma or injury, the result can be complex regional pain syndrome. This condition affects more women than men and occurs most frequently in people ages 40-60.

This syndrome is classified into two types.

CRPS-I is the classification when there is no verified nerve damage or trauma but the symptoms fit the syndrome.

CRPS-II is the classification when there is verified nerve damage as the cause of the syndrome.

Symptoms of complex regional pain syndrome

Symptoms of complex regional pain syndrome can vary from severe and debilitating to short and mildly uncomfortable. These can include the following:

  • Parethesia: Often called “pins and needles,” this is the sensation of mild burning and prickling of the skin. Skin may also feel tingly.
  • Allodynia: Allodynia is extreme sensitivity to touch, a sensitivity that may range from ticklish to very painful. This response is triggered by even just the slightest touch.
  • Prolonged pain: This might feel like someone is squeezing the limb and may be severe.
  • Change in skin temperature or color: This change is caused by the intermittent blood flow to the limb. When nerves are damaged, they are unable to maintain a steady flow of blood to the affected limb. Thus, the limb changes color and increases or decreases in temperature noticeably when blood is flowing or not. The limb may also appear blotchy and change color.
  • Swelling: In extreme cases, the limb can swell so much as to split the skin. If there is another condition present, such as diabetes, this can be very serious. Skin may appear shiny and thin before this happens.
  • Other symptoms: Stiffness in joints may also be present, as may abnormal sweating patterns or unusual hair or nail growth. The affected limb may be difficult to move as muscle control decreases, or the limb may jerk or remain fixed in an unusual way.

Causes of complex regional pain syndrome

This is not a common condition, but why do some patients develop complex regional pain syndrome while others do not? For starters, 90% of patients have clear evidence of trauma or injury. These injuries can be fractures, sprains, strains, bruises, burns, or cuts. They can also occur as a result of being in a cast or undergoing surgery. While most people sustain a broken ankle or a huge bruise and then go on to recover without developing complex regional pain syndrome, some have a severe reaction to the injury.

There is limited connection to genetic history as a cause of CRPS, but those with autoimmune disorders or other inflammatory responses have a higher incidence of complex regional pain syndrome than those without those conditions. Those with CRPS have a high level of cytokines, inflammatory chemicals released in reaction to some stimulus (physical or chemical). The extreme response to injury is almost like the body’s defense mechanism to the injury and seems to function in the same manner as an allergy.

Complex regional pain syndrome involves the small fibers in the nerves, causing blood vessels to open wide to leak fluid into the surrounding muscle and tissue. This response causes swelling, redness, and pain. When the small fibers cause constriction, blood vessels cut off the flow of blood and cause the affected limb to feel cold and become white or blue in tone. Those patients who have conditions that affect the blood vessels may be particularly susceptible to this response.

Patients who have nerve abnormalities in the small nerve fibers seem to develop this condition more frequently. The ends of the small nerve fibers are densely packed and very sensitive. They contribute to inflammation and abnormalities in the blood. In extreme cases, these abnormal small peripheral nerves can trigger abnormalities within the larger central nervous system, which can lead to neurological issues in brain function.

For those cases of complex regional pain syndrome that have no easily detectable injury as the cause, there may have been a previously undetected internal injury or infection. More often than not, there is more than one cause for this syndrome, and it is only by careful and thorough examination that a diagnosis can be made.

Treatment of complex regional pain syndrome

As with diagnosis, treatment is highly individualized and can vary in duration and frequency. Some of the most common treatments of conditional regional pain syndrome are below.

Counseling. Offered concurrent with other treatments, counseling is recommended to deal with the mental challenges of a chronic pain condition. Most doctors include this in their treatment plan to support the patient’s mental health and to help develop coping skills as they address the physical effects of complex regional pain syndrome.

Nerve block. This procedure involves inserting a fine needle through the skin and injecting a pain-reliever or numbing agent at the base of the nerves thought to be involved. This can produce immediate pain relief with long-lasting effects while other treatments are applied.

Physical therapy. Because the affected limb is painful, chances are good that the patient has avoided using it. Physical therapy restores strength, increases blood and oxygen to the limb, and broadens range of motion.

Peripheral nerve stimulation. Tiny electrodes are placed close to the affected nerve, and tiny currents of electricity are administered to provide pain relief.

Medication. Non-steroid anti-inflammatory drugs (NSAIDS), drugs for seizures and depression, topical creams, and corticosteroids have all been shown to be effective in relieving pain and inflammation when used early in the diagnosis. None of these have been approved by the U.S. Food and Drug Administration for specific use with CRPS, however.

Biofeedback. This is the process whereby patients learn to listen to the signals their body is sending (painful or otherwise) and then use that information to deal with the information. This is a meditative technique that can help patients access pain relief without a prescription any time they feel discomfort.

Although relatively rare, complex regional pain syndrome is a serious chronic condition. For more information on how to support yourself or someone who is experiencing CRPS, please take a look at the U.S. Department of Health and Human Services’s pamphlet on this condition.

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