What are the pathophysiologic theories leading to CRPS?

What are the pathophysiologic theories leading to CRPS?

Multiple theories have been proposed regarding the eti-ology of CRPS. Current accepted theories focus on both the peripheral nerves and the central nervous system. Peripheral etiologies for CRPS describe the existence of ephapses, or neurologic short-circuits between the somatic and sympathetic nervous systems, possibly caused by trauma. It is unclear whether these connections are actual structural connections or “chemical” connections caused by release of neurotransmitters. These ephapses could explain the clinical findings. Stimuli that are usually medi-ated by the autonomic nervous system, such as responses to emotion, temperature, and weather, are rerouted through the somatic nervous system and cause pain. Stimuli that are usually mediated via the somatic nervous system, such as light touch, are rerouted through the autonomic nervous system and cause an uncoordinated sympathetic response.

Central theories that try to explain the etiology of CRPS look at the wide dynamic range neurons in the dorsal horn of the spinal cord. These are neurons that nor-mally receive input from multiple types of nerve fibers and could serve as the anatomic correlate for the short-circuit connections between the somatic and sympathetic nervous systems.