HISTORY OF COMPLEX REGIONAL PAIN SYNDROME
Complex Regional Pain Syndrome (CRPS) has had a long and controversial history. Few diseases have had so many name changes, and different understandings over time as to why and how the syndrome occurs and ongoing discussion over the best method to diagnose the disorder.
This controversial history continues even today with debate about the influence of the autoimmune or genetic component of the disorder, the mechanism of spread, and whether we do indeed have the best diagnostic tool available, with several different criteria having been put forward and slightly altered over the years. Debate still occurs over the name 24 years after complex regional pain syndrome was decided upon by consensus from a panel of IASP members in 1994.
This is by no means a comprehensive history of CRPS, but details most of the significant history prior to 1900 and a little of the varied and complex history of the disease since that time.
CRPS was first documented by Ambrose Pare in the 16th Century. Ambrose was one of the most notable surgeons of the European Renaissance, regarded by some medical historians as the father of modern surgery.1 He was the personal physician to the French King Charles IX of Valois.
After treating the King for small pox by bloodletting around 1570, he described the ongoing burning, persistent pain the King experienced, along with muscle wasting, contractures and an inability to flex or extend his arm.1,2 This was described in his book Les Ouvres ď Ambroise Paré, King Charles IX, published in 1598. Pare had also noticed the presence of chronic pain following peripheral nerve injury in wounded soldiers.3
Two centuries later John Hunter described a sympathetic effect on muscles which atrophied and lost their power following trauma. He was the first to describe remote effects, away from the site of initial trauma, on the joints and muscles, without any known nerve injury in In Lessons on the Principles of Surgery, published in France in 1766.4
In the late 1700’s, Sir Percival Pott, a British surgeon, described “certain painful afflictions of the nerves” and recognised burning pain and atrophy in injured extremities.5
Following this in 1813 Alexander Denmark, another British surgeon that worked at the Royal Navy Hospital in the Hampshire, reported a case of a soldier who was wounded by a bullet that had passed through his upper arm. The wound itself healed quickly, however he noted in his report “I always found him with the forearm bent and in supine position and supported by the firm grasp of the other hand. The pain was of a ‘burning’ nature, and so violent as to cause a continual perspiration from his face”. Denmark linked the persistent, burning pain to the involvement of the radial nerve in the upper arm.1 Denmark successfully treated the patient with an above the elbow amputation.5
In 1838 Hamilton reported seeing some cases of patients that had burning pain resulting from accidental nerve injuries.
In 1851, Claude Bernard, a French neurologist, was the first to mention a pain syndrome that was linked to sympathetic nervous system dysfunction.6 He was also the first to describe the sympathetic nervous system as being responsible for internal temperature regulation of the body in 1878.7
In early 1864 Sir James Paget, a British surgeon, pathologist and surgeon to Queen Victoria, had patients with constant warmth in their limbs after a nerve injury.5
Also, in 1864, Claude Bernard’s student, Silas Weir Mitchell, considered the ‘father of American neurology’ together with George Morehouse & William Keen noticed the frequent occurrence and extreme pain related to the injuries from the veterans of the US Civil War. They gave a description of the disorder in Gunshot Wounds and Other Injuries of Nerves.
It finely described all of the signs and the symptoms characteristic of what we now call CRPS. They said “The skin affected in these cases was deep red or mottled, or red and pale in patches. The surface of all the affected part was glossy and shining as though it had been skilfully varnished. In other instances, there was associated with this, acute or aching pain which extended beyond the diseased tissues. It consists essentially of a painful swelling of the joints which may attack any or all of the articulations of a member. Once fully established it keeps the joints stiff and sore for weeks or months.”
It also said “Further study led us to suspect that the irritation of a nerve at the point of the wound might give rise to changes in the circulation and nutrition of the parts in its distribution, and that these alterations might be of themselves of a pain-producing nature”.1
Silas Weir Mitchell and Sir James Paget corresponded with each other to discuss their scientific findings regarding this disorder. Paget believed the disease was similar to frostbite, whereas Mitchell identified the role of the peripheral nerve injury and wrote that it was necessary to further investigate it’s features.1
The clinical condition was later called ‘Causalgia’ in Mitchell’s second book Injuries of Nerves and their Consequences published by Mitchell in 1872, however he stated that the term was coined by Robley Dunglison and published in the first edition of the Dictionary of Medical Science in 1874 from the Greek words ‘kausos’ (heat) and ‘algos’ (pain).1,8
The first person to make reference to post-traumatic bone rarefaction, or osteoporosis, was von Volkmann in 1882, who used the term post-traumatic osteitis and later by Destot in 1898 who noticed bone rarefaction following a long-term painful ankle sprain who also commented on the intensity of the pain.
In the 1880’s CRPS was a disease defined as ‘hysteria minor’ by French neurologist, Dr. Jean-Martin Charcot after observing dystonic movement disorder and contractions associated with the disorder. Charcot hypothesized that hysteria was generated by non-structural lesions in the nervous system which were likely to be biochemical or physiological in character.9 Unfortunately, even despite this early understanding, the sensory disorders and movement disorders of CRPS are still sometimes diagnosed as somatization disorders, or conversion disorders despite all the evidence that points to them being physiological rather than psychogenic in origin.
At the 29th Congress of the German Society of Surgery, in 1900, Paul Sudeck delivered a paper entitled ‘Acute inflammatory bone atrophy’, which described the results of his experiments on patients who had undergone X-ray examinations. He described examples of bone atrophy that sometimes persisted for a long time in an extremely disabling chronic form. Nonne, a student of Sudeck coined the name ‘Sudeck’s Atrophy’ in 1901– a name which is still in use in some parts of the world today.
During the first World War, Rene Leriche, a military surgeon in Strasbourg, hypothesised that the sympathetic nervous system played a major role in the origins of the signs and symptoms of the disease. In 1917 he described a patient who complained of chronic hand pain and numbness following a gunshot wound in the right armpit. Leriche performed the first periarterial sympathectomy and reported a complete resolution of the pain syndrome within 2 weeks.1 Leriche coined the term ‘Sympathetic Neuritis’ to show the role of the sympathetic nervous system in neuropathic pain.
The term ‘reflex sympathetic dystrophy’ was introduced just after World War II by James Evans who stressed the role played by the sympathetic nervous system to describe a condition similar to causalgia but without major nerve injury. Between 1946 and 1947 he described 57 patients with a chronic pain syndrome characterised by intense pain and clinical signs that he explained as ‘sympathetic stimulation’. This had appeared after fractures (21%), sprains (21%), vascular complications (19%), amputation (9%), arthritis or osteitis (5%) and lacerations (2%) or minor injuries including contusions (9%) and postural defects of the foot (7%).1,10
Evans noted that sympathetic blocks usually relieved the pain, confirming his hypothesis that it was connected to the sympathetic nervous system.
In 1973 John Bonica proposed 3 clinical stages of RSD as follows:1
– Stage 1 (acute), from the moment of the trauma to 3 months after, characterized by erythema, warmth, oedema, marked hyperhidrosis, a distribution of the pain not related to root nor nerve involvement, limited range of motion and reduced muscle strength with a negative X-ray examination, but a positive scintigraphy showing hyperaccumulation;
– Stage 2 (dystrophic), characterized by severe pain, oedematous skin, decreased hair growth, discoloration with cyanotic areas, persistent hyperhidrosis, muscle weakness and limited range of motion of the affected joint or joints;
– Stage 3 (atrophic), characterized by decreased but still disabling pain that improves with rest and worsens with passive movements. The skin could be atrophic, thin, dry, sometimes ulcerated, cold, mottled or cyanotic in toto; there could be loss of joint range of motion and muscle strength with tendon atrophy, contractures, tremors and dystonia determining a significant motor impairment of the affected limb. At this stage the radiographic examination shows inhomogeneous regional osteoporosis (Sudeck’s atrophy).
It was first suggested by Bonica that early diagnosis was critical in outcome of treatment.
John Bonica was instrumental in the foundation of the International Association for the Study of Pain (IASP) in 1973 after inviting delegates to an International Symposium on Pain. He also made sure that it was multidisciplinary, with all professionals interested in reducing pain and suffering invited to participate on an equal basis.10
To create diagnosis criteria for reflex sympathetic dystrophy a consensus conference was organized by the IASP in 1988 at Schloss Rettershof, near Frankfurt, and a second one in Orlando, Florida in 1993.
Bonica proposed to rename the disease as ‘Complex Regional Pain Syndrome’ (CRPS)’.
The name was changed to Complex Regional Pain Syndrome in 1994 and the Orlando Conference established that CRPS could be diagnosed in presence of the following conditions:6
The presence of an initiating noxious event or a cause of immobilization.
Continuing pain, allodynia, or hyperalgesia with which the pain is disproportionate to any inciting event.
Evidence at some time of oedema, changes in skin blood flow, or abnormal sudomotor activity in the region of pain.
This diagnosis is excluded by the existence of conditions that would otherwise account for the degree of pain and dysfunction.
According to IASP, CRPS is a syndrome characterized by a continuing (spontaneous and/or evoked) regional pain that is seemingly disproportionate in time or degree to the usual course of pain after trauma or other lesion. The pain is regional (not in a specific nerve territory or dermatome) and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor oedema, and/or trophic findings. The syndrome shows variable progression over time.
In the same conference in Orlando it was decided to differentiate between the form characterized by the evidence of obvious nerve damage (CRPS type II, corresponding to causalgia) and the form without demonstrable nerve lesions (CRPS type I).1
The Orlando criteria resulted in a large number of misdiagnosed patients. Stephen Bruehl and Norman Harden, both Pain Medicine specialists and members of the IASP Task Force on CRPS published two articles about a study carried out to test the internal and external validity of the Orlando criteria in 1999. The results of the study led to a proposal of a substantial revision of the Orlando criteria. The main change proposed by Harden et al. was to add clinical signs.1
Following this in 2003 in Budapest a further consensus conference put forward a new classification system. It proposed the presence of at least two clinical signs included in the four categories and at least three symptoms in its four categories.
The Budapest Criteria forms the basis of the diagnostic criteria still in use today.
1. Continuing pain, which is disproportionate to any inciting event.
2. Must report at least one symptom in three of the four following 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, dystonia) and/or trophic changes (hair, nails, skin).
3. Must display at least one sign* at time of evaluation in two or more of the following categories:
Sensory: Evidence of hyperalgesia (to pinprick) and/or allodynia (to light touch and/or deep somatic pressure and/or joint movement).
Vasomotor: Evidence of temperature asymmetry and/or skin colour changes and/or asymmetry.
Sudomotor/Oedema: Evidence of oedema and/or sweating changes and/or sweating asymmetry.
Motor/Trophic: Evidence of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nails, skin).
4. There is no other diagnosis that better explains the signs and symptoms.
*A sign is counted only if it is observed at time of diagnosis.
**Research criteria for CRPS are recommended that are more specific, but less sensitive than the clinical criteria; they require that four of the symptom categories and at least two sign categories be present.