Causative & risk factors
The exact cause of CRPS is not known. In most cases, a preceding history of injury may is present. It is thought to occur due to hypersensitivity of pain receptors to catecholamines. It can also result due to a faulty immune response causing inflammation at the affected site.
Clinical presentation
CRPS is characterized by severe, unremitting pain (burning, stinging or stabbing) that goes on worsening with time. There is usually a history of injury to the affected part. Even so the pain is extremely out of proportion to the extent of the injury. It may also spread to areas beyond the site of injury. For example, a finger injury may lead to severe pain along the entire arm. Mental stress can heighten the symptoms.
The affected part may be stiff and swollen. The hair growth on the affected region undergoes changes leading to rapid or no growth. Nails may become brittle.
CRPS produces several skin changes giving the affected part a purplish/reddish appearance, excessive perspiration or a shiny look. The skin temperature usually does not match the skin of the rest of the body; it being warmer or cooler in comparison.
The underlying bones may show osteoporotic changes.
Investigations
No specific tests are available to diagnose CRPS. The diagnosis is based upon the patient history and clinical assessment. Tests may be performed to eliminate other causes giving rise to pain at the affected site. These include blood tests, X-rays, MRI scans and nerve conduction studies. The levels of cytokines and calcium in the blood are usually found to be increased.
Treatment
Being an incurable disorder, the aim of treatment is to relieve the pain and prevent complications. Analgesics, anti-convulsants or anti-depressant drugs are prescribed depending upon the intensity of the pain. Cognitive behavioral therapy is an important aspect of treatment since incurable pain can drive the patient to depression or even suicide.
Sympathetic nerve blocks can provide pain relief to some patients.
Surgical sympathectomy is a possible treatment option for some patients. This procedure involves destruction of the nerves involved in CRPS.
Spinal cord stimulation offers pain-relief to many patients; it involves placement of electrodes next to the spinal cord.
Physical therapy is recommended to rehabilitate the patient.
Recent updates
Hyperbaric oxygen chamber therapy is a newer form of treatment for CRPS.
Currently research is underway to study the efficacy of intravenous immunoglobulin treatment for Complex regional pain syndrome.
