That's a difficult question to answer. Cases of CRPS "spreading" are limited to a small number of classic case reports and a small number of more recent case studies from academic tertiary-based pain treatment facilities. The "spreading" more likely represents dysfunction or chronic changes of the central nervous system (plasticity) at the level of the spinal cord and brain. Similar nervous system changes have been recognized in other chronic pain conditions. Maleki et al1 reviewed a number of CRPS/RSD "spreading" cases where they described three clinical scenarios: contiguous spread (higher up in the same limb), mirror image (same limb, opposite side), and independent spread. Most of the patients in this study with "spreading" also suffered some type of trauma or underwent some type of invasive procedure. A number of the mirror image cases were postulated to have developed from compensatory overuse of the other initially noninjured limb.

Recent clinical studies of CRPS patients have demonstrated manifestations of these changed in the nervous system. A patient, for example, who suffered a severe crush injury to the hand, was found to have pain and sensitivity to normal innocuous light touch (allodynia) and other changes of sensation and strength in the same contiguous. Similar changes in sensation and the presence of swelling was noted in leg on the same side of the body of the original trauma. More importantly, "spreading" of symptoms in the same limb or region of the body is more likely related to myofascial pain syndrome.

With respect to patients, this can be considered an important and viable target for treatment. Myofascial pain can be treated effectively with medications, active physical therapy, and other behavioral treatment techniques. Many times, appropriate treatment of the myofascial component of their pain problem can have significant and profound effects on reducing pain, increasing range of motion, improving posture, and returning patients to greater levels of function.

Is myofascial pain the same as fibromyalgia?
No. Although both are controversial muscle pain conditions, they are distinct clinical entities. Myofascial pain is a soft tissue disorder localized primarily to one region of the body, characterized by myofascial trigger points. Myofascial trigger points, are hyperirritable locations within an area of skeletal muscle fibers, that when compressed , can give rise to characteristic referred pain patterns and tenderness. For example, trigger points from the neck or cervical region can "refer" pain to the head. Other trigger point referral patterns from muscles along the lower back region can refer pain down the leg. Fibromyalgia, also a disorder of muscle sensitivity, is a syndrome characterized by widespread musculoskeletal pain. Although the clinical spectrum varies among patients, it generally involves more generalized muscle tenderness, above and below the waist (all four quadrants of the body), neuroendocrine effects, sleep and gastrointestinal disturbance, and psychological distress (depression and anxiety).

How do CRPS patients develop myofascial pain?
As with many other chronic pain conditions, normal pain mechanisms go awry. Inflammatory, autonomic, and neuropathic changes at the level or area of injury cause significant changes at the spinal cord and brain amplifying pain and dysfunction. Compensating for the injured limb over time causes long-term maladaptive changes in the body and supporting muscles. For example, protecting an injured hand with CRPS, may cause weakness or tightening in the supporting muscles of the shoulder and neck. These overused and deconditioned muscle groups are more likely to develop myofascial pain. Myofascial trigger points in the neck and shoulder can cause pain to radiate to the head (headache) or to the same or opposite limb. These painful and sometimes disabling symptoms may be misinterpreted by the patient and health care providers that the CRPS is "spreading."

How do you treat myofascial pain? Do injections work?
Yes, in some circumstances injections may be beneficial. Drs. Travell and Simons2 have meticulously described muscle patterns of pain with trigger points and a broad range of treatment approaches for aggressively treating myofascial trigger points. Active treatments include injection therapies, stretching exercises and other physical modalities (heat and ice). Common injection therapies include the use of local anesthetics, steroids and/or saline. Dry needle techniques and injection of botulinum toxin (Botulinum toxin A/ BOTOX) have more recently gained popularity in the field of pain management. Biofeedback assisted relaxation training may also be an effective tool patients can learn in reducing muscle tension and subsequent pain. Correcting postural abnormalities, strengthening and stretching muscle groups in the effected myofascial areas is a key component of any individual's treatment program. Many times, aerobic conditioning is also coordinated into the patient's treatment and home exercise program.

What is the incidence of myofascial pain with CRPS?
Published reports vary greatly between 60% and 80% of CRPS sufferers.

How about botulinum (Botox) injections for myofascial pain?
Botulinum toxin is a potent neurotoxin indicated for dystonia and spasticity. Its use for cosmetic purposes cannot be ignored either. The neurotoxin is injected directly into a trigger point. The toxin is thought to be effective in reducing muscle spasm at the site of injection and by causing changes in pain processing at the spinal cord. Recent animal and human research has also supported the toxin's possible additional analgesic effects. A number of studies of its potential use for myofascial pain, chronic tension type headache, and migraine have revealed conflicting results regarding its therapeutic benefit. Obviously, careful patient selection is an important factor. Neurotoxin injections or any other modality should not be used in isolation, but incorporated into a more comprehensive treatment program.

References

1. Maleki J, LeBel A, Bennett GJ, Schwartzman RJ. Patterns of spread in Complex Regional Pain Syndrome, type I. Pain. 2000;88:259-266.

2. Travell JG, Simons DG. Myofascial pain and dysfunction: the trigger point manual, the upper extremity. Vol 1. Baltimore: Williams & Wilkins; 1983.

Updated July 19, 2005