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.