Diagnosis of CRPS
CRPS (or RSD) can be difficult to diagnoseespecially early in the course of the disorder. Diagnosis often involves taking a thorough medical history and performing a neurological examination, and requires excluding other conditions that produce similar symptoms (called differential diagnosis). During the neuro exam, the clinician may notice that the response to mild sensory stimuli produces severe pain.
Physical examination involves observing the skin color and temperature, any swelling, vascular reactivity, overgrown and grooved nails, swollen and stiff joints, and muscle weakness and atrophy.
Other conditions are ruled out with appropriate testing, such as triple phase bone scan, magnetic resonance imaging (MRI scan), a full laboratory panel, electrophysiological studies of the nerves and muscles (e.g., EMG, NCV), and a thermogram (test that uses an infrared video camera to measure the emission of heat from the affected limb). EMG and NCV tests can be used in combination and are often referred to as EMG/NCV studies.