Chronic Pain Syndromes: Complex Regional Pain Syndrome.

Complex regional pain syndrome (CRPS) is a chronic pain condition characterized by intense pain, usually in a body region that has experienced trauma, and autonomic and inflammatory features. It most commonly develops after an arm or leg injury. Patients typically present with extreme hyperalgesia and/or allodynia. The Budapest Criteria are used to make this clinical diagnosis. Prompt diagnosis and aggressive management are critical because long-term outcomes are improved when treatment is initiated soon after symptom onset. The primary management options are rehabilitation and physical therapy, including such approaches as progressive tactile stimulation, normalization of movement to prevent limited range of motion, and others. No drugs are approved by the Food and Drug Administration (FDA) for CRPS management, but some evidence supports the use of drugs used to manage other types of neuropathic pain (eg, gabapentin, tricyclic antidepressants, serotonin-norepinephrine reuptake inhibitors). Nonsteroidal anti-inflammatory drugs also are used, and corticosteroids, bisphosphonates, ketamine, and other drugs can be helpful, particularly for early-stage CRPS. When pain severity prevents patients from participating in rehabilitation, referral to a pain specialist is warranted for consideration of procedural interventions, including sympathetic nerve blockade and spinal cord stimulation.