Complex Regional Pain Syndrome (CRPS)

Other names: Reflex Sympathetic Dystrophy (RSD), algodystrophy, causalgia.

What is Complex Regional Pain Syndrome (CRPS)?
Complex regional pain syndrome (CRPS) is a pain syndrome that we do not fully understand. It can be brought on after an injury such as a broken wrist, or surgery. It is believed to be the result of imbalance and dysfunction in the central or peripheral nervous systems. CRPS is characterized by pain, swelling, stiffness, colour changes and a fine tremor in the affected extremity. The pain is out of proportion to the injury that triggered it. The nerves becomes overactive, causing intense burning or aching pain, along with swelling and changes in skin colour and moisture. The pain is often constant and the skin hypersensitive to stimuli that would not normally be painful. For example the pressure from the sleeve of a jumper may cause an unpleasant feeling in the skin.

The exact incidence of CRPS is unknown. This is because there is no single test to make the diagnosis. Many cases go undiagnosed as the majority of cases will make a good, if not full recovery. It may occur as often as in 5% of all injuries. It occurs in up to 15% of peripheral nerve injuries and following 10-30% of fractures.

Who gets CRPS?

The causes of CRPS are not known. Fractures and sprains are the most common precipitating events, CRPS more commonly affects the upper extremities. CRPS can also begin after surgery. In some cases there is a pre-existing compression of a nerve such as carpal tunnel syndrome. It is most common among individuals between 25 and 55 years of age, though anyone of any age can be affected. CRPS is three times more likely to occur in women than men.

Signs and Symptoms of CRPS

Here are symptoms of CPRS:

The key symptom of CRPS is continuous, intense pain out of proportion to the severity of the injury (if an injury has occurred). CRPS most often affects one of the extremities and is also often associated with the following symptoms:

“Burning” pain

Increased skin sensitivity

Changes in skin temperature: warmer or cooler compared to the opposite extremity

Changes in skin colour: often blotchy, purple, pale, or red

Changes in skin texture: shiny and thin, and sometimes excessively sweaty

Fine tremor of the affected limb

Changes in nail and hair growth patterns

Swelling and stiffness in affected joints

You may hear the following medical terms:

hyperalgesia – when you are extremely sensitive to pain

allodynia – when you feel pain from something that should not be painful at all, such as a very light touch

In more severe cases of CRPS, muscles in the affected limb may begin to waste (atrophy). This usually occurs if the person affected is unwilling to use their limb due to associated pain.

Stages of CRPS

Here are the known stages of CPRS:

Symptoms of CRPS usually progress in three distinct stages. However, not everyone will experience all possible symptoms, or progress through all three stages, which are outlined below.

Stage one
This first stage usually lasts from one to three months, and is characterised by an intense, burning pain in one of your limbs. You may experience:

muscle spasms (when muscles contract tightly and painfully)

joint stiffness

rapid growth of hair and nails

Blood vessels in your limb will also be affected, causing a change in skin colour and temperature.

Stage two
The second stage of CRPS usually lasts from three to six months. The pain in your affected limb may get worse, and the skin colour and texture changes may be more pronounced. Symptoms of swelling and stiffness become more severe, and muscle tone in your affected limb will begin to weaken.

Stage three
The third stage of CRPS is the last stage of the condition. At this point, any changes to your affected limb are likely to be irreversible. These may include:

significant loss of muscle tone

bones of the limb may have become contorted (bent out of shape)

joints may be stiff

you will probably find it very difficult to use or move your limb

It is important to get a prompt diagnosis and have treatment started to minimise the long term disability/damage.


There is no single test to confirm a diagnosis of CRPS. The diagnosis is primarily through observation of signs and symptoms. Patients must be examined by a qualified doctor/surgeon who will ask detailed questions about events related to the symptoms and perform a thorough physical examination.

It may take more than one visit to confirm the diagnosis as other conditions need to be ruled out. Investigations such as X-rays, scans and electrical tests (EMG/NCV) may be helpful. Consultation with other specialists may be needed, and a pain clinic appointment is often recommended.


General principles of managing CPRS:

General principles
The key approach is a multidisciplinary one but should be centred around the GP and Pain teams.

Care has to be taken so that the patient’s care does not become fragmented, as they may end up seeing several different specialties.

Good progress can be made in treating CRPS if treatment is begun early, ideally within three months of the first symptoms.

Pain flares may occur but usually settle over a few weeks. Medications should be continued with a temporary reduction in intensity of physical therapy.

The Royal College of Physicians provide four ‘pillars’ of therapy: education, pain reduction, physical rehabilitation and attention to psychological needs, aiming to improve the quality of life.

The earlier the diagnosis of CRPS is made and treatment started, the better the chance for recovery. Treatment is varied and depends on both the severity of the symptoms and the duration of the problem. It is important to maintain general fitness -aerobic conditioning, relief of sleep disorders, and treatment of psychological problems can be helpful for treatment. Some patients may have an associated trapped nerve that needs to be addressed. Since there is no simple cure for CRPS, treatment is intended to relieve painful symptoms, minimise the long term problems of stiffness and impaired function.

The following may used in the management of CRPS:

This should be considered in all cases and started early, as soon as the diagnosis is considered. A multidisciplinary approach is needed. Treatment approaches used in rehabilitation for CRPS are wide and include education and support, desensitisation, postural control and oedema control. In addition to this, specialised units may also undertake more specialised therapeutic strategies – e.g., mirror visual feedback and graded motor imagery.

Psychosocial factors may lead to reduced response to rehabilitation and should be actively looked for and corrected. This includes previous negative experiences, poor coping, and depression. CRPS can have profound psychological effects on patients and their families. Many with CRPS have depression, anxiety, or post-traumatic stress disorder. A psychologist or psychiatrist may be able to improve coping ability and motivation as well as detect and address any substance dependency issues.

Nerve Blocks
Many patients experience significant relief from nerve blocks, in which local anaesthetic is injected to numb nerves. By relieving pain, blocks can enable more effective therapy, improve mood, and improve level of activity. Stellate ganglion blocks may be used to numb the stellate ganglion, which is a cluster of sympathetic nerves at the base of the neck, in an effort to reduce the over-activity of the sympathetic nerves seen in CRPS

Simple analgesics (painkillers) are used to begin with. These are adjusted by your doctor as required. If pain is not reduced to a mild level by 3-4 weeks then use medication for neuropathic pain – eg, tricyclic antidepressants or gabapentin/pregabalin.

Limb use should also be encouraged with gentle exercise, frequent attention to the affected limb, and desensitisation (using various fabric modalities whilst observing the limb).

Medications may also be needed for associated disturbance of sleep or depression if present.

Pamidronate as a one-off treatment can be given to patients with CRPS of less than six months duration.


If the CRPS is from a compressed nerve, such as with carpal tunnel syndrome, then surgery to release pressure on the nerve may be needed (e.g., carpal tunnel release). Rarely, an operation known as sympathectomy is used to divide the sympathetic nerves in patients who are helped by nerve blocks, and its use is controversial.


The duration of CRPS varies: in mild cases it may last for weeks followed by remission; in a few severe cases the pain continues for years and, in some cases, indefinitely. It is estimated that 15% have unrelenting pain and physical disability at two years. Some patients experience periods of remission and exacerbation.


Investigators are studying new approaches to treat CRPS and intervene more aggressively after traumatic injury to lower the patient’s chances of developing the disorder. It is important to minimise swelling after an injury or operation by elevation of the affected part and early movement where this is possible. This will require adequate analgesia after an injury or surgery.

It is also important that dressings or plaster casts are not applied too tightly. There is evidence that high dose vitamin C may reduce the occurrence of CRPS after wrist fractures. It is not known at present if this applies to CRPS after other injuries or surgery. In the studies a daily dose of 500 mg for fifty days was used.

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