ALTERED PHYSICAL FUNCTION, QUALITY OF LIFE, AND DISABILITY

Patients with CRPS will face significant quality of life consequences as this pain syndrome dramatically alters their lives as well as the lives of their families and friends. As noted previously, the effects of CRPS can potentially lead to permanent disability. Galer et al. noted that a majority of patients felt that symptoms caused “substantial interference” with general activities (74%), mood (74.2%), mobility (67.7%), normal work (74.2%), relations (64.5%), sleep (67.7%), and social activities (74.2%). Interference in self-care was identified in 45.2%. This study also noted the mean duration of CRPS in the 31 patients surveyed to be 3.3 years. The need to use a device, such as a cane, walker, or wheelchair, was reported by 35% of the participants. The participants in the Galer study reported moderate to severe pain intensity with substantial disability.⁵⁹ A survey of CRPS patients by the RSD Foundation found that 23% of the respondents had to stop daily activities occasionally due to pain, 74% had to stop them frequently due to pain, and 87% suffered from constant or nearly constant pain.⁶⁰ These reports confirm that CRPS can have a very constricting effect on functional capacity. Caregivers of 51 CRPS patients were reported to suffer significant strain, low mood and poor adjustment.⁶¹ A study of 65 patients noted 30% of RSD patients had to stop work for more than a year. (See Figure 6.) They also noted high rates of unemployment and financial compensation, establishing RSD as a disabling disease.^{62, 63} In the retrospective chart review of 134 patients, 54% had a workers’ compensation claim related to the CRPS, and another 17% had a lawsuit. This is consistent with another study noting that 64% of those surveyed had a work related injury resulting in their symptoms.^{64, 65} CRPS is a syndrome that causes millions of Americans to suffer from chronic, unremitting pain.

WHAT ARE THE MECHANISMS BEHIND CRPS?

The mechanisms triggering the pain as well as the associated changes that occur in patients with CRPS remain largely obscure. As with other factors surrounding CRPS, the pathophysiology is also unclear. Divergent theories abound since the spectrum of presentations of this syndrome is so diverse.⁶⁷ Multiple components have generally been proposed as the pathophysiological mechanisms, and hypothesis include a neuropathic mechanism which is sympathetically maintained, an immunological mechanism including inflammation, and an altered expression of human leukocyte antigens. The hypotheses exist for both peripheral and central mechanisms. None of this data however is conclusive.⁶⁸ They may include the somatic and visceral sensory systems, the central control systems, the sympathetic nervous systems, the somatomotor system, and the neuroendocrine systems.⁶⁹ These systems are further differentiated to include the following symptoms noted in CRPS: (1) The nociceptive system: spontaneous pain, hyperalgesia, allodynia. (2) The sympathetic nervous system: abnormal regulation of blood flow and sweating. (3) Sympathetic nervous system, afferent system: edema of the skin and subcutaneous tissues. (4) Sympathetic system, afferent system, somatomotor system: trophic changes of skin, appendages of skin, and subcutaneous tissues. (5) Somatomotor system: active and passive movement disorders, including physiological tremor.⁷⁰ A more recent mechanism set forth in explaining the pathophysiology of CRPS is an inflammatory response. An unknown stimulus induces an excessive production of inflammatory mediators, leading to an imbalance in production and clearance of toxic radicals. This excessive production of oxygen radicals results in destruction of healthy tissue.⁷¹ (See Figure 7.)