What is Complex Regional Pain Syndrome?
Complex Regional Pain Syndrome
Complex regional pain syndrome (CRPS) is severe, long-lasting pain and inflammation that develops after an injury to an arm or leg. It was once called reflex sympathetic dystrophy (RSD) or causalgia (1). People with CRPS have an exaggerated pain response, so something as mild as a light touch on the affected area can become severely painful.
CRPS should be diagnosed and managed with your physician, and early diagnosis and treatment matter. If you are struggling with thoughts of harming yourself, call or text 988 to reach the 988 Suicide & Crisis Lifeline, or call 911.
How Common Is CRPS?
CRPS is estimated to affect about 200,000 people a year in the U.S. It affects women three to four times more often than men. It most often begins around age 40, though it can begin anywhere from the late 30s to 70, and it is most common in people of European ancestry (2).
What Are the Early Signs of CRPS?
Early signs of CRPS include episodes of severe, shooting or burning pain or “pins and needles” in one area of an arm or leg. These may come on by themselves or be triggered, and they may pass quickly or last for several minutes. Triggers can include a light touch, a breeze or cold air on the skin, or clothing brushing against the area.
Other symptoms that may come with the pain include:
Pain that is stronger or lasts longer than expected after using or touching the area
Changes in the temperature, color or swelling of the affected limb
Changes in skin texture
Unusual sweating in the area
Unusual hair and nail growth on the limb
Stiff joints
Thinning of the bone, or extra bone growth
Weakness and trouble moving the limb
What Are the Later Symptoms of CRPS?
Over time, episodes may last longer or happen more often. CRPS that lasts longer than six months is considered chronic. Many people with CRPS improve over time, but for some it becomes severe and disabling. How CRPS progresses varies a great deal and depends on many factors, including overall health, age, circulation, nutrition, smoking, diabetes and past chemotherapy (1).
What Causes CRPS?
In more than 90% of cases, CRPS follows an injury to the affected area, such as a fracture, surgery, sprain or strain, burn or cut, time in a cast, or even a minor needle stick (1). Poor circulation can slow nerve and tissue healing, and conditions like diabetes or exposure to nerve toxins can leave nerves more vulnerable. This can lead to poor nerve recovery and make the nerves that carry pain signals more excitable.
What Happens in the Nervous System With CRPS?
CRPS is thought to involve abnormal activity in small nerve fibers, called C-fibers, that carry pain-related signals, called nociception, to the brain. Increased firing of these fibers also triggers inflammation, the same response the body uses to heal injuries.
It’s important to understand that pain is not just a sensation. It is a perception and an experience created by the brain. Most people think of their pain system as an on-off switch, so if they aren’t feeling pain, the system must be off. But that’s not how it works.
Your body has sensors called nociceptors that respond to heat, cold, chemical irritants and pressure. When they’re stimulated enough, they send signals through small nerve fibers into the spinal cord. Like other nerve cells, they always have some background level of activity. So why aren’t we in pain all the time?
The answer is that your spinal cord and brainstem have systems that filter and block these signals before they reach the conscious parts of your brain. When there is enough input, such as from tissue damage or inflammation, these filters are overwhelmed, and the signal reaches the parts of the brain that map the body, mainly in the parietal lobe. Even then, the signal doesn’t become pain until the brain attaches a negative emotional meaning to it. That doesn’t mean pain is imaginary. It means pain is real and is shaped by the brain, which is also why the brain is an important target for treatment.
The brain’s pain-control circuits are normally very good at blocking incoming signals before they reach awareness. These circuits involve the frontal and prefrontal cortex, the parietal lobe, the vestibular system, the brainstem and the spinal cord. After an injury, pain signals help the body heal by directing blood flow and inflammation to the injured tissue. Once healing happens, those signals need to be turned back down.
Research has found changes in the frontal and prefrontal cortex in people with CRPS (3). In CRPS, the brain can become very efficient at producing pain, while the areas that normally turn it down don’t work as well.
Other brain areas shape how unpleasant pain feels. The amygdala helps detect threats and process fear. The hypothalamus and pituitary gland release stress hormones that help us respond to threats, and some of these hormones can make pain sensors more sensitive. The anterior cingulate cortex is involved in the experience of suffering, and when it’s highly active, pain signals feel more distressing.
Chronic pain is best understood as a loss of balance between the systems that send pain signals and the systems that turn them down, combined with emotional distress that keeps the pain experience going. In acute pain, pain signals tell your brain that tissue has been injured. In chronic pain, these signals persist and grow stronger, and they may continue long after the tissue has healed.
Normally, when you stub your toe or burn your hand, the signal travels from your skin to your spinal cord and up to your brain. Your brain locates the problem, triggers healing, and the pain fades. In chronic pain, these pathways can overreact, and pain can continue weeks later. This is called central sensitization. When the pain-control systems don’t turn the signals back down after healing, the pain nerves keep firing and become more sensitive. Eventually, light touch, gentle pressure and even the normal chemical environment of the body can trigger pain (4).
Chronic pain also changes the brain’s maps of the body. As the brain’s map of the affected area is reorganized by ongoing pain signals, the brain may have more trouble knowing exactly where that body part is, and more trouble sending signals to turn down the pain coming from it (5).
The brain areas involved in the unpleasant side of pain also change in chronic pain. The anterior cingulate cortex can become highly sensitized (4). Many people with chronic pain notice that negative emotions feel stronger than before their injury and that negative thoughts are harder to manage. This is one reason depression and anxiety are so common with chronic pain (6).
These changes can also affect the body’s stress system, called the hypothalamic-pituitary-adrenal axis, raising stress hormone levels, which can further feed chronic pain (7). They also promote inflammation in the spinal cord and brain, which can make it even harder to turn pain down (8).
The result is that pain responses can become exaggerated and long-lasting. Pain can become disconnected from tissue damage and continue long after the tissue has healed, or in response to normal everyday sensations. The emotional effects of chronic pain can also spill into every part of a person’s life, affecting mood, motivation and thinking (4).
Many people with chronic pain move from provider to provider and try increasingly invasive treatments aimed at the injured tissue. When pain continues after the tissue has healed, it often means the nervous system itself has changed, and those changes need attention too.
How Is CRPS Diagnosed?
CRPS is diagnosed by a physician based on a detailed medical history and a physical and neurological exam, using specific clinical criteria. Other tests may help (1):
Nerve conduction studies, which may find some, but not all, nerve injuries linked to CRPS.
Ultrasound or MRI, which can sometimes show nerve damage or changes in bone and bone marrow.
Triple-phase bone scans, which sometimes show the bone changes linked to CRPS.
How Is CRPS Usually Treated?
Early diagnosis and treatment are important, since research shows the brain changes differently in early and long-standing CRPS (9). Common treatments include (1):
Physical therapy and rehabilitation, a key treatment for CRPS. Keeping the affected joints and muscles moving can improve blood flow to the area and help prevent the changes in the spinal cord and brain that come from not using a limb (10).
Occupational therapy, to help people stay active and return to work and daily activities.
Psychotherapy, because people with severe CRPS often develop depression, anxiety, fear of movement or post-traumatic stress. These can increase pain and make it harder to stay active and take part in therapy.
Medications to reduce pain and inflammation, taken by mouth or applied to the skin.
Spinal cord stimulation.
Sympathetic nerve blocks, which are used less often now because long-term benefits haven’t been shown.
Other approaches, such as behavior change, relaxation techniques and acupuncture, which help some people.
How the NeuroRescue Program Can Help
Our care is designed to work alongside your physician, pain specialist and therapists, never in place of them. Please don’t change or stop any medication without talking with your prescriber.
Our care focuses on the nervous system side of CRPS: the pain-control systems that are supposed to turn pain signals down. These systems involve the frontal and prefrontal cortex, the parietal lobe, the vestibular system, the brainstem and the spinal cord, with the goal of helping restore a better balance between pain signals and pain control.
To move through and interact with the world, you first need to know where the world is. Saccades are fast eye movements that shift your gaze between targets, and they need to be fast, accurate and quick to start. The vestibulo-ocular reflex (VOR) lets you turn your head while keeping your eyes on a target, and it needs to match your eye movements precisely to your head movements. Many of the same brain areas involved in pain control, including the frontal and prefrontal cortex, the parietal lobe, the vestibular system and the brainstem, also control these eye movements and reflexes, and research suggests they may be affected in CRPS. Our testing measures them carefully, and your program may include precise exercises to train them, with the goal of supporting the brain systems that help control pain.
Research suggests spinal adjustments may do more than move a joint. Studies using EEG, brain stimulation and brain imaging have found that adjustments can produce short-term changes in how the brain processes sensory and movement information, including in the prefrontal cortex and the areas that plan and control movement (11, 12, 13, 14). Researchers are still working to understand how long these changes last and how they relate to symptoms, but they help explain why we look at how your whole nervous system is working, not just the painful area. Chiropractic adjustments may be part of your care when appropriate and safe for you.
Depending on your needs and test results, your program may also include:
Vestibular rehabilitation.
Graded motor imagery and mirror therapy. Graded motor imagery is a step-by-step program that retrains the brain’s map of the affected limb. It starts with recognizing whether pictures show a left or right hand or foot, moves on to imagining movements, and then uses mirror therapy, where a mirror image of your unaffected limb gives your brain a pain-free picture of the affected one. In a small randomized controlled trial of people with long-standing CRPS, graded motor imagery reduced pain, and the benefit was repeated when the comparison group later received the same program (15). A randomized trial in stroke survivors with CRPS of the arm found that mirror therapy reduced pain and improved movement (16, 17). Results haven’t been the same in every study. A 2024 trial found that adding mirror therapy to routine rehabilitation didn’t provide extra benefit (18), so we use these methods as part of a broader, carefully graded program.
Electrical stimulation to support pain control (19).
Cold laser therapy applied to the affected area, which has been studied for CRPS (20).
Transcranial magnetic stimulation (TMS), which has been studied for the anxiety and depression that often come with chronic pain (21). At our clinic, TMS is provided by our psychiatric mental health nurse practitioner, who will evaluate whether it may be appropriate for you.
No two cases of CRPS are alike, and the same is true for your NeuroRescue Program. The therapies we recommend are always chosen based on your testing and exam findings, and we pace your program carefully so it challenges your nervous system without flaring your pain.
How the NeuroRescue Program Works
Your NeuroRescue Program begins with your Discovery Day. We start with a detailed history of your condition and your life on a timeline. This helps us understand the factors that may have contributed to where you are now, and identify related conditions that may be making it harder to move forward. For CRPS, this includes factors such as circulation, nutrition, smoking, blood sugar problems or diabetes, and past medical history, such as chemotherapy.
We measure how your visual, vestibular and balance systems are working through computerized analysis of your eye movements, inner ear reflexes and balance under different conditions. Our testing includes videonystagmography and saccadometry to measure several types of eye movements, the video head impulse test to measure inner ear reflexes, and CAPS computerized posturography to assess your balance under different sensory conditions. We also use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye tracking and your perception of vertical in a virtual reality environment.
We combine this with a thorough physical and neurological exam of your sensory, motor, autonomic and cognitive systems. We also review any relevant lab work, imaging and prior testing, and integrate it with our findings.
Together, this helps us understand which parts of your nervous system are working well, which are struggling, and how quickly they tire. We use that information to design your personal NeuroRescue Program, aimed at improving function in the systems that need support and helping them work together. Our testing also helps us decide when to push and when to let you rest.
Our goal is to help turn the volume down on your pain, so you can use your arm or leg, sleep better and get back to more of the things you enjoy.
Your Next Step
Living with CRPS can be exhausting and isolating, especially when people can’t see how much you hurt. You don’t have to face it alone. To find out if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.
It’s never too late to take the next step.
References
