Snapshot A 65-year-old woman with a history of dementia falls onto her outstretched right hand and sustains an extra-articular distal radius fracture. Her fracture is reduced and immobilized in a fiberglass cast. She is seen 1 week post-reduction without any significant concerns. However, she is lost to follow-up temporarily and returns to clinic 3 months later. At cast removal, it is noted that her forearm is swollen, shiny, and erythematous. The limb is extremely tender to light touch over the entire length of her forearm, and small movements at the wrist elicit burning pain. Radiographs reveal bony union of the fracture and generalized osteopenia of the carpal and forearm bones. Introduction Clinical definition abnormality of a body region that is characterized by pain and swelling vasomotor instability skin changes patchy bone demineralization impaired range of motion Epidemiology Demographics more common in women and patients > 30 years of age Etiology Complex regional pain syndrome (CRPS) typically occurs after a precipitating injury such as surgery soft tissue injury fracture Pathogenesis may involve both central and peripheral mechanisms; however, the exact mechanism is unclear Presentation Symptoms and physical exam pain autonomic symptoms changes in skin temperature and color sweat edema sensory abnormalities e.g., hyperalgesia and allodynia functional motor impairments trophic changes e.g., increased hair growth in the affected region and skin atrophy Imaging Radiography indication can be used in the workup of patients with CRPS findings patchy osteoporosis Bone scintigraphy indication can be used in the workup of patients with CRPS findings increased radiotracer uptake may be seen Studies Thermography, sweat testing, x-rays, electrodiagnostics, and sympathetic blocks can assist in diagnosis Differential Diabetic neuropathy distinguishing factor patients will have a history of uncontrolled diabetes Guillain-Barre syndrome distinguishing factor classically presents as an ascending paralysis with decreased or absent reflexes typically following an upper respiratory or gastrointestinal infection Compartment syndrome distinguishing factors the affected compartment is typically tense and swollen pain is elicited by stretching of the muscle that is compressed Raynaud phenomenon distinguishing factor notable skin changes (white, blue, or both) following exposure to cold temperatures DIAGNOSIS Making the diagnosis primarily a clinical diagnosis Treatment Conservative physical and occupational therapy indication considered first-line in patients with CRPS patient education is also integral to managing this patient population Medical pain management indication to improve pain as patients continue their physical and occupational therapy medications nonsteroidal antiinflammatory drugs (NSAIDs) gabapentin bisphosphonates tricyclic antidepressants Complications Chronic pain Disability Prognosis Many of the symptoms may resolve within a year