What is Complex Regional Pain Syndrome (CRPS)?

From the Guidelines

Complex Regional Pain Syndrome (CRPS) is a chronic pain condition characterized by excruciating pain, often made worse by touch or stimulation, which gradually increases in intensity and size in the affected limb, sometimes spreading to the contralateral limb. This condition, also known as sympathetically maintained pain, causalgia, or reflex sympathetic dystrophy (RSD), usually follows an injury, often minor, and is associated with hair loss, tissue changes, and skin discoloration at the site of the pain 1. The exact prevalence of CRPS is unknown, but it has been reported in patients living with HIV (PLWH) 1.

Key Characteristics of CRPS

• Excruciating pain that is disproportionate to the original injury
• Pain made worse by touch or stimulation
• Gradual increase in intensity and size of the affected area
• Possible spread to the contralateral limb
• Associated with hair loss, tissue changes, and skin discoloration
• Sympathetic dysregulation is proposed to play a role in the development of CRPS 1

Treatment Approach

While the provided evidence does not extensively discuss treatment options, a multidisciplinary approach is typically recommended for managing CRPS, including medications, physical therapy, and psychological support. It is essential to note that early diagnosis and treatment are crucial for better outcomes, as CRPS can become more difficult to treat over time. Further information on the management of CRPS can be found in reviews such as the one by Freedman and colleagues, as referenced in the guideline 1.

From the Research

Definition and Characteristics of Complex Regional Pain Syndrome (CRPS)

• Complex Regional Pain Syndrome (CRPS) is a heterogeneous disorder that falls in the spectrum of neuropathic pain disorders 2.
• It is characterized by significant sensory, motor, and autonomic dysfunction, often following trauma or nerve injury 3.
• CRPS is distinguished by severe, disproportionate pain, often accompanied by hyperalgesia, allodynia, trophic changes, and motor impairments 3.
• The condition can be classified into two types: type I (without nerve injury) and type II (associated with nerve damage) 3.

Pathophysiology of CRPS

• The pathophysiology of CRPS is not fully known, but it is believed to involve abnormalities throughout the neuraxis (the peripheral, autonomic, and central nervous systems) 2.
• Potential peripheral pathophysiologic targets include increased spontaneous firing and responsiveness of peripheral afferent fibers, altered levels of expression and functioning of multiple ion channels, and abnormal interneuronal communication 2.
• Central mechanisms, such as reorientation of dorsal horn terminals, functional reduction in inhibitory interneuron activity, and central sensitization, also play a role in the development and maintenance of CRPS 2.

Diagnosis and Treatment of CRPS

• The diagnosis of CRPS relies primarily on clinical evaluation using criteria such as the Budapest Criteria, supported by supplementary tests to exclude differential diagnoses 3.
• The management of CRPS necessitates a multidisciplinary approach combining physical therapy, psychological support, and pharmacotherapy 3.
• Treatment options include bisphosphonates, glucocorticoids, vasoactive mediators, and physical therapy, as well as interventional modalities like spinal cord stimulation and dorsal root ganglia stimulation 3, 4.
• There is low-certainty evidence that bisphosphonates may reduce pain intensity, but the certainty in the evidence for other interventions is very low, providing insufficient evidence to either support or refute their use 5.