How is the diagnosis of CRPS made?
The diagnosis of CRPS is a clinical one, made by the his-tory and physical examination. There is no one test that can make the diagnosis definitively.
The most commonly used diagnostic test involves blocking the sympathetic innervation to the affected area and noting any improvement in the clinical symptoms. Another modality that has been described is a continuous intravenous phentolamine infusion.
Indirect measures of sympathetic function that can be used to diagnose CRPS include skin probes and infrared thermography to measure temperature changes to the area affected, peripheral somatosensory mapping for allodynia/hyperesthesia, triple-phase bone scans, and sweat testing.