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Complex regional pain syndrome: what it is about

Complex regional pain syndrome: what it is about

Complex regional pain syndrome (CRPS) is a painful and long-lasting condition. The different stages of CRPS usually cause chronic, constant and burning pain in the arm or leg affected by this condition.

It is not easy to trace the cause of CRPS, but it is thought that the cause is triggered by damage to the nerve fibres in the injured tissue. Smoking is a risk factor for the condition.

Experts believe that when you suffer from Complex Regional Pain Syndrome your nerves become excessively sensitive and therefore the perception of painful signals is even more intense than normal.

Even the most common stimuli, such as simply touching the skin, are perceived by the patient.

Although the cause of CRPS remains unknown, it is thought that this disorder may be triggered by damage to nerve fibres in the tissue that has been injured. Smoking is a risk factor for the condition.

Experts believe that if you contract Complex Regional Pain Syndrome you will feel a greater nervous sensitivity, which implies a greater perception of pain to the point of feeling painful even just touching the skin or temperature changes.

This condition usually begins after an injury or other event. Examples include traumas, fractures, infections, surgery, strokes or the use of a plaster cast. Often, the injury that triggers CRPS is mild compared to the pain that follows. However, the condition may also follow more severe injuries or paralysis. Pain is often not limited to the area that has been injured.

This condition can occur at any age, but there are more cases in postmenopausal women.

Complex Regional Pain Syndrome has been called by many other names. These include reflex sympathetic dystrophy syndrome (RSDS), algodystrophy, causalgia, shoulder hand syndrome, Sudeck atrophy and transient osteoporosis. 



Symptoms of the different stages of Complex Regional Pain Syndrome may include:

  • Intense pain, palpitations, burning and swelling, usually in the hand or foot.
  • Thin and shiny skin around the affected area
  • Initially increased, but subsequently decreased the hair on the affected are
  • Fragile and thickened nails
  • Dry and withered skin
  • Skin warmer or cooler than usual
  • Skin that changes colour
  • Increased sweating

The condition can progress in three stages CRPS. However, not everyone deals with CRPS through every phase.

In the first of the Complex Regional Pain Syndrome phases, which occurs over days to weeks after an injury, the limb can become dry, warm, red and painful. Even the slightest touch or movement can cause atrocious pain.  These symptoms suggest that it is another disease, so your doctor may not be able to confirm your diagnosis of CRPS at this stage.

In the second of the CRPS phases that characterizes the following weeks, the skin may become shiny, thin and fresh. The limb fills up with patches and takes on a purplish colour and becomes swollen. In this CRPS phase the pain becomes more intense, and the nails become fragile and can grow faster or slower than normal. Problems with movements occur and there is a strong pain that is probably related to stiffness and muscle soreness.

Some people have other movement problems, including weakness, spasm and tremor. An affected limb can become permanently flexed or bent. In some people, the skin may become tight, dry, and wrinkled. Bones can become brittle because they are not used. The skin, muscles and joints stiffen so that the affected area cannot be moved. Some patients have less pain at this point. Once the disease reaches this point, it is extremely difficult to treat.


The different  CRPS stages

Stage 1

The first fase CRPS is usually lasts between 0 – 3 months and the name is disfunction stage.

It is an acute phase. The symptoms are extreme burning pain that is more intense than would be considered normal from the injury. The pain is stabbing with conspicuous functional limitation, continuous or discontinuous, exacerbated by the load and the functional request. Allodynia is present and hyperpathia, with intolerance sometimes to the simple touch.

Sometimes there is faster hair growth, faster nail growth and excessive sweating. There may be changes in circulation of the affected limbs, mainly concerning the blood vessels in that they may be constricted or even obstructed. This may cause skin changes going from red to blue or black, purple or white.

The skin may look blotchy or spotty when the colour changes occur. The extremity may have temperature changes either warmer or cooler than other limbs or extremities. It is often clear especially in the tibia larynx and in the foot a warm and diffuse swelling.

Instead, in the hip is almost exclusively present ache. As the CRPS progresses this phase will give way to the chronic phase and the Complex Regional Pain Syndrome affected limb will become ‘Cold CRPS’.

Stage 2

The stage 2 of CRPS stage appears after the 2nd month or between the 2th month and the 4th month,  and the symptoms are cold, inelastic skin, and associated deficiency of joint excursion. Loss of elasticity also in connective tissues, including tendons and joint capsules. Non-use hypermyotrophy is associated. In the hip it is characterized by pain and joint limitation. It is known also as the dystrophic stage because of the muscle weakness due to the lack of use of the limb/extremity.

The burning pain becomes much worse and usually spread from the initial area. The hypersensitivity will become even more sensitive to any form of touch, the muscles and the limb will become stiffer. You will avoid moving the extremity to get away from the pain because it is so swollen you won’t be able to move it.

The skin may also become dry or withered, because of the lack of circulation or poor oxygen in the blood. You may also see that your nails near the concerned limb or extremity tend to be brittle so they will break or crack a lot more easily. The temperature will carry on going between hot and cold, however it will tend to become cooler, and we can find osteopenia, the bone mass reduction.

Stage 3

Usually it occurs after 6 months but more often after 1 year. It is called atrophic stage. The symptoms are: the skin around the affected area that tends to be paler, stretched, shiny, cool to the touch and dry. Ulcers and cracks in the skin may become apparent and may become infected. Nails will become rigid. Hair becomes brittle. There may be spreading of the condition to other parts of the body.

Severe bone mass reduction will be seen and if the Complex Regional Pain Syndrome is in the hands or arms the fingers will become thin and long. Osteoporosis, for instance, can sometimes be seen on x-rays and radiographs and loss of minerals in the bone. There can be a contraction of the segments concerned and a limitation of articular excursions and the functionality of the district concerned. In the hip it is manifested by the limitation of joint excursion.

The temperature of the affected area will now tend to be cooler than when it was in the earlier stages. By this stage there are many problems like tremors, spasms, severe jerking and possibly dystonia.

Stage 4

Finally there is the  advanced of CRPS stages that is the stage 4. Other RSD symptoms present in the other 3 CRPS stages are present within this stage. Damage to the affected limb may become irreparable. The severe constant burning pain is still ever present, and osteoporosis may also be more noticeable within this stage. Cellulite and gangrene can occur due to the complications of CRPS on internal organs and specialist may require the limb to be amputated so that any infection will stop spreading. Beyond the ethical and medico-legal implications, today it is not clear if the amputation can have, only for the most serious and obstinate cases, a role in therapy.

The diagnosis can be formulated on the basis of the Budapest criteria defined in 2003 under the aegis of International Association for the Study of Pain (IASP) described in a table. This table shows four criteria, indicated with the letters A), B), C), and D), which must to be all satisfied so that CRP can be diagnosed. The criteria B) and C) are satisfied considering some categories of signs and symptoms which must be present in number one or two depending on the criterion considered. The signs and symptoms are grouped into 4 categories (sensory, vasomotor, sweating, edema, motility-tropism of the tissues).


In the early stages of CRPS before many of these features develop, diagnosis is difficult or impossible. In later stages, X-rays sometimes show bone loss, especially in the area around the joints. Bone scans can help confirm the diagnosis. But the condition cannot be diagnosed with a single bone scan.

Tests can be made to assess nerve function.

These tests are used to look for nerve damage or other causes that may have damaged the nerves. These tests are called electromyography and nerve conduction studies.

Some doctors use other specialized tests to help diagnose this condition. As an assessment of the nerves that regulate skin sweating and skin temperature. This can be done by measuring sweat production and skin temperature.

With the thermogram it is possible to map the skin temperature in different points of the body. This shows the regular blood flow in the different areas, and the abnormal blood flow in the area affected by Complex Regional Pain Syndrome.

Expected life

Some people with CRPS improve without treatment. But timely treatment improves the chances of relieving pain.

A wide range of drugs have been, and still are, used for the treatment of CRPS with various dosages and in various association. The pharmacological class offering the greater efficacy for many years are bisphosphonates, especially neridronate and anti-inflammatories. Above all, they are commonly used to contain signs of inflammation. Corticosteroids administration have shown to be large usefulness in the treatment of early CRPS stages of disease.


There is no way to prevent CRPS because the cause is unclear. However, physical activity or physical therapy after a stroke can prevent CRPS.

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