The disease Complex Regional Pain Syndrome (CRPS) is a rare nerve disorder. Its symptoms usually cause intense pain, and affected areas are typically the hands, arms, legs and feet. It usually appears after a serious injury to the tissues or nerves in the affected areas. The disorder is also called Causalgia. Some changes observed in the affected areas are changes in the color and temperature of the skin of the affected limb. Other symptoms can be skin sensitivity, intense burning pain, swelling and sweating. The reasons the disorder occurs are currently unknown. Although there are some theories behind the cause of this disorder, the authenticity of them is questionable. One theory is that the pain is caused within the sympathetic nervous system. Another speculation is that CRPS is caused by triggering the immune response, leading to inflammation in the affected area.
Occurrence and Treatment
CRPS is rare, estimates range from one in 4000 in some countries and one in 18,000 in others (approximately 1 in 11,000.) It is most common among women between the ages of 50 and 70.
Although it is a rare disorder, most doctors are familiar with it. The doctor will diagnose CRPS based on a physical exam and the pain symptoms, and look at the skin temperature and blood circulation. Although the disease is diagnosable, there is not a single test that can determine CRPS. An MRI can help to make the diagnosis.
Treatment is often a sympathetic nerve block, involving an injection of anesthesia, which blocks pain signals. Often, physical therapy and counselling may also help.
Types of CRPS
There are two types of Complex Regional Pain Syndrome, with different triggers.
Type One CRPS is triggered by injuries such as sprained or fractured ankles. There is usually minimal nerve damage. Type Two CRPS is caused by more serious injuries where there has been nerve damage, such as from an operation, serious infection or broken bone.
Clinical Features of CRPS
CRPS patients usually have a history of an inciting event, such as a nerve or tissue injury (sprain, fracture, surgery) or a period of immobilization. In most cases, the severity of the clinical presentation is disproportionate to the inciting event. The syndrome may also be triggered by stroke, spinal cord injury, visceral disorders such as myocardial infarction and cholecystitis, or more trivial events, such as bruising, and venipuncture (blood draw or injection.) Prolonged use of a surgical tourniquet and psychological stress have also been implicated. Interestingly, some patients with neck pain after whiplash injury exhibit features of CRPS including dystonia.
Patients with CRPS typically present with neuropathic-type pain (tearing, burning, shooting or aching), allodynia (mechanical and cold stimuli), hyperalgesia, oedema, vasomotor changes (constriction or dilation of the blood vessels), sudomotor changes and in severe cases, dystrophy and atrophy of the nails, skin, hair, muscle or bone. Symptoms and signs occur in a regional distribution and not in the area of a peripheral nerve or nerve ending in the skin.
A syndrome with all of the features of CRPS, without the pain, has also been noted. Some authorities have proposed distinct clinical stages; however, the validity of this approach is questionable given the variable clinical course of the disorder. The symptoms of CRPS may spread within the region, or in mirror image fashion- appearing in the opposite side of the body in the same region, or independently- appearing in a foot after appearing in the hand. In some cases, spread is associated with a new inciting event.
Abnormalities in sensory testing, such as the decreased sensation to light touch, pin prick and vibration, may be found in the affected region and adjacent areas. There is a higher incidence of motor impairment and mechanical allodynia in patients with widespread sensory impairment. Many patients with CRPS develop neglect-like symptoms similar to those seen after a stroke in the affected limb. Patients have reported that the feeling in their arm or leg does not seem to belong to them any longer (cognitive neglect) or having to think harder to make the limb move (motor neglect). Phantom sensations such as strange limb postures or the feeling of having extra body parts have also been described.
These abnormalities in limb movement and posture may reflect the development of fear-avoidant pain behaviors, or motor dysfunction. Causalgia-dystonia syndrome is characterized by clenched fist or foot, early onset of contractures, and the spread to other limbs. Many patients with CRPS develop areas of myofascial dysfunction and may have trigger points within the muscles of the affected limb, especially in the arm and shoulder. The incidence of myofascial dysfunction is higher in patients with motor neglect or long-standing symptoms. Physiological factors such as depression, anxiety, and post-traumatic stress disorder are common, with 80% of patients reporting a stressful life event immediately before the onset of their CRPS. Social and occupational problems, such as loss of employment, or disruption of family life, are frequently present.
Prevention and Post-Operation Minimization of CRPS
Prevention is avoidance of trauma and unnecessary surgery, early mobilization and rehabilitation of an injured body part and management of psychological factors such as depression, anxiety and fear-avoidance. Programs to increase awareness of Complex Regional Pain Syndrome among medical practitioners may facilitate earlier diagnosis and treatment.
Strategies to minimize recurrent CRPS after surgery should include a pre-operative assessment of the patient by a pain management specialist, and the development of a treatment plan. Indications for surgery should be reviewed, as there are reports of surgery being performed to treat a painful mechanical condition, when the pain was actually due to CRPS. Surgeries should be limited in extent and duration, particularly avoiding nerve injury and prolonged tourniquet use. In some cases, intravenous regional blockades with clonidine and lignocaine, or administration of vitamin C may reduce recurrence. Sympathetic analgesia, including ketamine and calcitonin may also prove beneficial. Post-operative immobilization, such as splinting, should be minimized and physiotherapy should occur as soon as possible.
CRPS is indeed a complex disorder in terms of pathology, diagnosis and treatment. It is a multi-system disease typified by widespread nervous system dysfunctions and regional tissue inflammation. Patients need to take care to attend their physical therapy after injury, in order to avoid the occurrence or recurrence of Complex Regional Pain Syndrome.