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Complex regional pain syndrome (CRPS) is a form of chronic pain that usually affects an arm or a leg. CRPS typically develops after an injury, a surgery, a stroke or a heart attack. The pain is out of proportion to the severity of the initial injury.

CRPS is uncommon, and its cause isn’t clearly understood. Treatment is most effective when started early. In such cases, improvement and even remission are possible.

Causes of CRPS

The exact cause of CRPS is still unknown. It develops due to a soft-tissue injury, sprain or strain, surgery, stroke, infections, or a heart attack. CRPS may result from a combination of many factors, such as:

  • General inflammation in the region
  • Abnormal immune response in the affected region
  • Inaapropriate sensitivity of the pain receptors
  • Abnormal pain perception by the brain

Many factors determine whether someone would develop CRPS or not. For example, genetics, type of injury, region involved, and inappropriate inflammatory or immune response.




Signs and symptoms of CRPS include:

  • Continuous burning or throbbing pain, usually in the arm, leg, hand or foot
  • Sensitivity to touch or cold
  • Swelling of the painful area
  • Changes in skin temperature — alternating between sweaty and cold
  • Changes in skin color, ranging from white and blotchy to red or blue
  • Changes in skin texture, which may become tender, thin or shiny in the affected area
  • Changes in hair and nail growth
  • Joint stiffness, swelling and damage
  • Muscle spasms, tremors and weakness (atrophy)
  • Decreased ability to move the affected body part

Symptoms may change over time and vary from person to person. Pain, swelling, redness, noticeable changes in temperature and hypersensitivity (particularly to cold and touch) usually occur first.

Over time, the affected limb can become cold and pale. It may undergo skin and nail changes as well as muscle spasms and tightening. Once these changes occur, the condition is often irreversible.

CRPS occasionally may spread from its source to elsewhere in the body, such as the opposite limb.

In some people, signs and symptoms of CRPS go away on their own. In others, signs and symptoms may persist for months to years. Treatment is likely to be most effective when started early in the course of the illness.

When to see a doctor

If you experience constant, severe pain that affects a limb and makes touching or moving that limb seem intolerable, see your health care provider to determine the cause. It’s important to treat CRPS early.


The cause of CRPS isn’t completely understood. It’s thought to be caused by an injury to or difference in the peripheral and central nervous systems. CRPS typically occurs as a result of a trauma or an injury.

CRPS occurs in two types, with similar signs and symptoms, but different causes:

  • Type 1. Also known as reflex sympathetic dystrophy (RSD), this type occurs after an illness or injury that didn’t directly damage the nerves in the affected limb. About 90% of people with CRPS have type 1.
  • Type 2. Once referred to as causalgia, this type has symptoms similar to those of type 1. But type 2 CRPS occurs after a distinct nerve injury.

Many cases of CRPS occur after a forceful trauma to an arm or a leg. This can include a crushing injury or a fracture.

Other major and minor traumas — such as surgery, heart attacks, infections and even sprained ankles — also can lead to CRPS.

It’s not well understood why these injuries can trigger CRPS. Not everyone who has such an injury will go on to develop CRPS. It might be due to an interaction between your central and peripheral nervous systems that isn’t typical and different inflammatory responses.

Diagnosis of CRPS

It isn’t easy to make the diagnosis of CRPS, but the following provide clues to the doctor:

  • Medical History: Your signs and symptom give important clues about your condition. Your doctor will also ask you about any previous injury, surgery, or other significant event relating to your health.
  • Physical examination: Your doctor will palpate the affected region to check for pain, temperature and texture changes, and other associated symptoms.
  • Specific tests such as bone scans, X-rays, and sweat production tests help identify changes in the affected region and rule out other conditions.
  • The doctor may confirm the diagnosis with a sympathetic nerve block.

Prognosis of CRPS

Complex regional pain syndrome has no cure. The treatment options only help control the symptoms and perform daily activities. Many treatment options are available for this purpose, and it may take time to make an effective treatment combination.

Treatment of CRPS

Your doctor will recommend a combination of the following treatment options:

  • Over-the-counter pain relievers: OTC pain relievers such as naproxen and aspirin help relieve pain and inflammation temporarily.
  • Prescription pain relievers: Your doctor will prescribe more potent medicines when OTC pain-relievers don’t relieve pain. These include opioids (codeine), antidepressants (amitriptyline), and anticonvulsants (gabapentin) and treat neuropathic pain.
  • Topical agents like capsaicin cream may help reduce sensitivity.
  • Corticosteroids: These may improve inflammation and improve mobility, i.e., prednisone.
  • Applying ice and heat alternatively to the affected area
  • Physical therapy helps improve mobility of the affected joint and the other regions.
  • Mirror therapy and other brain desensitizing therapies to reduce pain perception



Interventional Pain Management

If your pain does not respond to these treatment options, your doctor may recommend interventional pain management. It utilizes various pain-blocking techniques to help perform daily activities. These options include:

  • Sympathetic nerve blocks: Sympathetic blocks like stellate ganglion block for hand and lumbar sympathetic block for legs have an essential role in treating CRPS.
  • Your doctor may use an anesthetic to block nerve fibers that carry pain impulses to the brain. Continuous brachial plexus block, continuous epidurals have essential roles.
  • Intrathecal drug pumps: These pumps deliver pain-relieving medications into the spinal cord.
  • Transcutaneous electric nerve stimulation (TENS): In TENS, electric stimulation of the nerve fibers stops nerve transmission and relieves pain.
  • Spinal Cord stimulation: Your doctor may also recommend stopping nerve impulse transmission in the spinal cord using tiny electrodes.
  • Surgery: It is the last resort in the past, and its use was controversial. In a surgical intervention, a surgeon resects the sympathetic nerves involved in pain transmission to relieve pain. But with the advent of percutaneous radiofrequency and cryoablation techniques, surgical sympathectomies are obsolete.



If CRPS isn’t diagnosed and treated early, the disease may progress to more-disabling signs and symptoms.

  • Tissue wasting (atrophy). The skin, bones and muscles may begin to deteriorate and weaken if you avoid or have trouble moving an arm or a leg because of pain or stiffness.
  • Muscle tightening (contracture). You also may experience tightening of the muscles. This may lead to a condition in which the hand and fingers or the foot and toes contract into a fixed position.


These steps might help you reduce the risk of developing CRPS:

  • Taking vitamin C after a wrist fracture. Studies have shown that people who take a high dose of vitamin C after a wrist fracture may have a lower risk of CRPS compared with those who didn’t take vitamin C.

Early mobilization after a stroke. Some research suggests that people who get out of bed and walk around soon after a stroke (early mobilization) reduce their risk of developing CRPS.