Complex regional pain syndrome

Complex regional pain syndrome
Other names	Algodystrophy; Amplified musculoskeletal pain syndrome; hyponym: reflex sympathetic dystrophy (RSD); hyponym: causalgia; hyponym: reflex neurovascular dystrophy (RND)
Leg of an individual (left) with complex regional pain syndrome following tibial bone fracture
Specialty	Neurology, psychiatry, anesthesiology
Symptoms	Pain, allodynia, hypo- or hyperesthesia, skin temperature abnormalities, atrophy, stiffness
Treatment	Physical therapy (more effective with early diagnosis); medications (e.g., anticonvulsants, opioids, muscle relaxers, etc.); sympathetic nerve blockade; ketamine infusions; lidocaine infusions; implantable pharmaceuticals; amputation
Medication	Anticonvulsants (e.g., gabapentin); muscle relaxers (e.g., baclofen), ketamine or lidocaine infusions[citation needed]

Complex regional pain syndrome (CRPS Type 1 and Type 2), sometimes referred to by the hyponyms Reflex Sympathetic Dystrophy (RSD) or Reflex Neurovascular Dystrophy (RND), is a rare and severe form of neuroinflammatory and dysautonomic disorder causing chronic pain, neurovascular, and neuropathic symptoms. Although it can vary widely, the classic presentation occurs when severe pain from a physical trauma or neurotropic viral infection^[1] outlasts the expected recovery time, and may subsequently spread to uninjured areas. The symptoms of types 1 and 2 are the same except type 2 is associated with nerve injury.

Usually starting in a single limb, CRPS often first manifests as pain, swelling, limited range of motion or partial paralysis, and/or changes to the skin and bones. It may initially affect one limb and then spread throughout the body; 35% of affected individuals report symptoms throughout the body.^[2] Two types are thought to exist: CRPS type 1 (previously referred to as reflex sympathetic dystrophy) and CRPS type 2 (previously referred to as causalgia). It is possible to have both types.^[3]

Amplified musculoskeletal pain syndrome, a condition that is similar to CRPS, primarily affects pediatric patients, falls under rheumatology and pediatrics, and is generally considered a subset of CRPS type I.^[4]