Complex Regional Pain Syndrome (CRPS) is an uncommon chronic pain condition that can affect the arms, legs, hands or feet of a patient, following an injury. Rarely, Complex Regional Pain Syndrome affects other parts of the body.
Complex Regional Pain Syndrome accounts for approximately 2% to 5% of adult pain clinic patients and up to 20% of paediatric pain clinic patients. The prevalence in Australia is unknown however, we do know that in adults, females are three times more likely to develop the condition than males.
Little is known regarding the cause and prognosis of Complex Regional Pain Syndrome. The severity of the patient’s symptoms varies greatly, as does the duration of the condition. There is no simple cure and rather treatment is aimed at restoring function and movement to the affected limb.
The causes of Complex Regional Pain Syndrome are not very well understood. It is thought that Complex Regional Pain Syndrome is caused by an injury to, or an abnormality of, the peripheral and central nervous system. Many cases occur following a forceful trauma to the limb for example a crushing injury, penetrating injury, fracture or amputation.
There is limited data to show that there may be a genetic connection and occasionally Complex Regional Pain Syndrome can develop without any known injury. There are two types of Complex Regional Pain Syndrome. Patients who have not had a confirmed nerve injury are classified as having Complex Regional Pain Syndrome type 1 which was previously known as reflex sympathetic dystrophy syndrome. Patients who have had a specific nerve injury are classified as having Complex Regional Pain Syndrome type 2, previously known as causalgia. About 90% of people with Complex Regional Pain Syndrome have type 1.
The Diagnostics and Symptoms
There is no specific diagnostic investigation for Complex Regional Pain Syndrome, rather the diagnosis is based on the clinical examination, and the patient’s history and presenting symptoms. Investigations are often performed as a way of excluding other diagnoses.
Over the years the diagnostic criteria for this condition has changed, and in 2003 the International Association for the Study of Pain (IASP) attempted to provide a more helpful and robust diagnostic framework called the Budapest Criteria which, in the last decade, has become the most commonly used criteria for the diagnosis of Complex Regional Pain Syndrome.
|International Association for the Study of Pain (IASP)– Budapest Criteria|
|1. Continuing pain, which is disproportionate to any inciting event.|
|2. Must report at least one symptom in each of the following four categories:|
. Sensory: Reports of hyperalgesia and/or allodynia.
. Vasomotor: Reports of temperature asymmetry and/or skin colour changes and/or skin colour asymmetry.
· Sudomotor/Oedema: Reports of oedema and/or sweating changes and/or sweating asymmetry.
. Motor/Trophic: Reports of decreased range of motion and/or motor dysfunction (weakness, tremor and dystonia) and/or trophic changes (hair, nails and skin).
|3. Must display at least one sign at the time of evaluation in all of the following categories:|
· Sensory: Evidence of hyperalgesia (to pinprick) and/or allodynia (to light touch and/or temperature sensation and/or deep somatic pressure and/or joint movement).
· Vasomotor: Evidence of temperature asymmetry and/or skin colour changes and/or skin colour asymmetry.
· Sudomotor/Oedema: Evidence of oedema and/or sweating changes and/or sweating asymmetry
. Motor/Trophic: Evidence of decreased active range of motion and/or motor dysfunction (weakness, tremor and dystonia) and/or trophic changes (hair, nails and skin).
|4. There is no other diagnosis that better explains the signs and symptoms.|
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