neurologic disorders
Complex Regional Pain Syndrome (CRPS)
Diagnosis of CRPS
Clinical evaluation Complex regional pain syndrome is diagnosed when the following are present: Patients have continuing pain beyond that explained by dysfunction of a single nerve and that is disproportionate to any original tissue damage. Certain clinical criteria (Budapest criteria Diagnosis reference ) are met. The Budapest criteria have four categories. For CRPS to be diagnosed, the patient must report at least one symptom in three of the four categories, and the clinician must detect at least one sign in two of the same four categories (symptoms and signs overlap): Sensory: Hyperesthesia (as a sign, to pinprick) or allodynia (as a sign, to light touch, deep somatic pressure, and/or joint movement) Vasomotor: Temperature asymmetry (> 1° C as a sign) or asymmetric skin color changes Sudomotor or edema: Sweating changes, sweating asymmetry, or edema Motor or trophic: Trophic changes in skin, hair, or nails, decreased range of motion, or motor dysfunction (weakness, tremor, dystonia) Also, there must be no evidence of another disorder that could explain the symptoms. If another disorder is present, CRPS should be considered possible or probable. Bone changes (eg, demineralization on x-ray, increased uptake on a triple-phase radionuclide bone scan) may be detected and are usually evaluated only if the diagnosis is equivocal. However, on imaging tests, bone may also look abnormal after trauma in patients without CRPS, making abnormalities detected by x-rays and bone scans nonspecific. In one test of sympathetic involvement, a patient is given IV infusions of saline (placebo) orphentolamine1 mg/kg over 10 minutes while pain scores are recorded; a decrease in pain afterphentolaminebut not placebo indicates sympathetically maintained pain. Sympathetic nerve block (cervical stellate ganglion or lumbar) has been used for diagnosis (and is used for treatment). However, false-positive and false-negative results are common because not all CRPS pain is sympathetically maintained and nerve block may also affect nonsympathetic fibers. 1.Harden RN, Bruehl S, Stanton-Hicks M, Wilson PR: Proposed new diagnostic criteria for complex regional pain syndrome.Pain Med8 (4):326–331, 2007. 