Complex Regional Pain Syndrome (CRPS)

What is Complex Regional Pain Syndrome?

Complex Regional Pain Syndrome (CRPS) is a constellation of symptoms, the hallmark of which is pain out of proportion to an injury, involving an extremity of the body. It commonly involves the hand, arm, foot, or lower leg. The cause of CRPS is unknown, and all aspects of the disease, from diagnosis to treatment are constantly being re-defined as physicians and researchers attempt to better understand the illness.

What causes Complex Regional Pain Syndrome?

There are currently two recognized types of CRPS. Both types involve injury to the affected limb. Type I is caused by indirect, presumed, trauma to the nerves of an extremity. Type II is caused by a well-defined, direct injury to a specific nerve (or nerves) in the extremity. Type I accounts for the vast majority of cases of CRPS.

In Type I CRPS, nerve damage does not occur directly, but the healing and inflammatory response to injury is thought to affect nerve function. One cause of type I CRPS is immobilization. Immobilization may occur iatrogenically by the placement of a plaster cast following a fracture, or may occur in the patient who protectively guards the limb following a minor injury. For this reason, frozen shoulder syndrome and biceps tendinitis are linked to CRPS of the hand. Crush injuries to an extremity, or soft tissue injuries, like a sprain or strain, have been shown to cause type I CRPS.

Type II CRPS results from direct injury to a specific nerve. An example would be a severed nerve due to an amputation or nerve damage sustained from a fracture.

What are the symptoms of Complex Regional Pain Syndrome?

Pain which is out of proportion to the injury sustained is the hallmark of CRPS. The pain is described as burning, stinging, tingling, or throbbing and is worse when the affected limb is moved. The pain is not limited to the distribution of a single nerve or group of nerves as would be expected with a nerve injury, but instead involves a region of the extremity which cannot be explained by nervous system innervation. Mobility may be decreased due to pain with movement, and the patient may claim extreme mental focus is needed to make the limb to move. Movement of the limb causes marked fatigue. Swelling, increased sweating, and temperature changes of the skin are also common, with both warmth and chill experienced. Some experience discoloration of the skin and changes in the hair and nails of the affected extremity.

Symptoms may begin immediately to weeks after the traumatic event. Most cases of Type I CRPS will resolve within 18 months, those which last longer have a poorer prognosis.

How is Complex Regional Pain Syndrome Diagnosed?

CRPS is a diagnosis of exclusion. All other explanations for the symptoms must be excluded. A complete workup should be performed to exclude nervous system disease, vascular disorders, psychological disorders, metabolic disorders, autoimmune disorders, infectious disease, and exposure to toxins.

A full panel of blood tests will help rule out many other possible diagnoses. Electromyography and Nerve Conduction studies, along with vascular studies of the affected limb will be helpful. X rays, bone scans, and MRI are employed to look at the bony and soft tissue changes that may occur in CRPS. While not diagnostic of the condition, these findings will help guide treatment options.

Quantitative Sensory Testing can objectively document hot and cold sensation and pain response. Autonomic Function Testing can measure skin temperature changes and the sweating response seen in CRPS.

How is Complex Regional Pain Syndrome Treated?


The pain and dysfunction of CRPS can be lessened with pain medications. Over the counter pain medications or prescription pain relievers may be used depending on severity. Sometimes, opioid narcotics may be needed to adequately control pain. Oral corticosteroids, given for a short period of time, improve symptoms. Some antidepressant medications and anti-epileptic medications have proven useful in pain caused by damaged nerves and work well in CRPS.

Anesthetics can be administered intravenously or transcutaneously in a nerve block to alleviate pain.

Physical therapy is useful to restore or maintain range of motion of the affected limb.
In refractory cases of pain, a transcutaneous electrical nerve stimulation (TENS) device may be placed, which is thought to block the ability of the nerve to sense pain. A series of stellate ganglion nerve blocks in the neck is usually beneficial.


Options for surgical relief include placement of a spinal cord stimulator or surgical sympathectomy.

How can Dr. Knight help you with CRPS?

CRPS is one of the most debilitating pain conditions in the world, and Dr. Knight recognizes this fact and will work hard to make sure that you are relieved of your pain. Dr. Knight a long with his pain management colleagues will greesively treat this condition to the best of their ability until a reasonable progress is made, and the pain is controlled as much as medically possible and through aggressive therapy, function returned.

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Disclaimer does not offer medical advice. The information presented here is offered for informational purposes only. Read Disclaimer