Complex regional pain syndrome abbreviated as CRPS and formerly referred to as reflex sympathetic dystrophy RSD, reflex neurovascular dystropohy or causalgia is an AMPS –amplified musculoskeletal pain syndrome. This syndrome is a chronic systemic illness characterized by swelling, skin change and severe pain. Complex regional pain syndrome progresses over time. This condition initially affects a leg or an arm and with tome, it will spread to the rest of the body. About 35% of the people suffering from complex regional pain syndrome have reported symptoms in all parts of the bodies.
Other potential effects of the syndrome include neurogenic edema, endocrine, dermatological manifestation and changes in the gastrointestinal or urological function. Complex regional pain syndrome is linked to the dysregulation of the autonomous nervous system and central nervous system which results in impairment, disability and functional loss.
Complex regional pain syndrome is divided into two based on nerve lesion presence after the injury.
Type I – Formerly referred to as RSD, Reflex neurovascular dystrophy (RND), algoneurodystrophy or Sudeck’s atrophy. This type does not exhibit nerve lesion and since it is the most common syndrome, it is referred to as Type I.
Type II – This type was formerly referred to as causalgia and will exhibit obvious nerve damages. Patients with Type II complex regional pain syndrome will have symptoms that are difficult to control and extremely painful. This type has a McGill pain scale score of 47 out of 50. The cause of the syndrome in Type II is the nerve injury but the mechanism behind the syndrome is as unknown in Type II as it is in Type I complex regional pain syndrome.
The exact cause of is unknown though there are precipitating factors that have been identified and these include surgery, injury, with a number of documented cases showing the existence of where there was no injury. While complex regional pain syndrome is not caused by psychological factors, the reduced quality of life and the experienced pain are known to cause some psychological issues such as anxiety and depression. Evidence has suggested that complex regional pain syndrome is connected to both psychological and physical factors. Treatment is complex and may involve drugs psychological treatments, neuromodulation, and physical therapy and is unsatisfactory especially when started late.
Complex regional pain syndrome has been found to have features such as nociceptive sensation, maladaptive neuroplasticity, vasomotor dysfunction and neurogenic inflammation. Initially, the symptoms of complex regional pain syndrome will show at the site of an injury which is typically minor. The most common symptoms described by complex regional pain syndrome patients include varying pain sensations such as burning, stabbing, throbbing and grinding. Touching or moving the affected limb becomes intolerable.
Most patients will also experience local swelling, muscle spasms, abnormally increased sweating, skin temperature changes, skin color changes, extreme sensitivity to things such as vibrations, touch and water, joint tenderness of stiffness, thinning and softening of bones and painful or restricted movement. Some patients have reported falls, fainting and visual impairment. There is a possibility of visual osteoporosis and the symptoms will vary in duration and severity. Because the condition is systematic, any body organ might be affected.
The pain caused by complex regional pain syndrome is continuous and is known to be worsened by physical or emotional stress. The exact cause is unknown but nerve damage has been suggested to be behind the condition in most cases. This suggestion is supported by the fact that disruption of pain signaling of some nerves can result in alleviation of symptoms.
Researchers have suggested that about 5% of people with peripheral nerve injury and between 13 and 17% of people with hemiplegia will develop complex regional pain syndrome. Studies have also shown that cigarette smoking was a contributing factor as it was present in a good number of patients and has been statistically linked to RSD. About 7% of patients with complex regional pain syndrome in one limb were found to develop the condition in the other limb. The mechanisms behind the condition are not known and the biggest suspect remains nerve damage.
Complex regional pain syndrome Type I and Type II are diagnosed using similar methods. The doctor will check for a history of skin blood flow abnormalities, edema, or abnormal sweating in the affected area. There will be ruling out of conditions that might cause the dysfunction and the pain. The two types will only differ in the inciting event. Type one complex regional pain syndrome occurs after a noxious event which may or may not be related to trauma while Type II will be as a result of injured or damaged nerve.
For this reason, the diagnosis for type I will focus on the presence of noxious event or an immobilization cause, continuing pain hyperalgesia, or allodynia. This condition will also have changes in skin blood flow, abnormal sudomotor activity and edema evidence. This should also include the exclusion of a condition that might cause similar symptoms. Type II complex regional pain syndrome is diagnosed through the same method as Type one only that there is no checking of an existing initiating noxious event or immobilization cause.
Tests that may be used include radiography, thermography and Electrodiagnostic testing.
There is not much information about the prevention of the disorder but vitamin C has been found to be useful in preventing the syndrome after a forearm fracture.
Treatment of complex regional pain syndrome is multidisciplinary; meaning that there needs to be a combination of different treatment methods. Occupational and physical therapy may be used in the management of the condition and will desensitize the affected area, improve function and restore motion. Some of other conservative methods include tactile discrimination training, graded motor imagery, and mirror box therapy.
Medications used in treating complex regional pain syndrome may include antidepressants, corticosteroid injections, anti-inflammatories, opioids, COX-inhibitors, beta and alpha-adrenergic-blocking. In moments of intense pain, butorphanol may be used. The use of low-dose naltrexone has been found to be effective in the remittance of major symptoms including fixed dystonia and dystonic spasms. If conservative treatment fails, surgery, sympathectomy and amputation may be used.