Diagnosis is primarily based on clinical findings. The original diagnostic criteria for<unk>  adopted by the International Association for the Study of<unk>  (IASP) in 1994 have now been superseded in both clinical practice and research by the ‘‘Budapest Criteria” which were created in 2003 and have been found to be more sensitive and specific. They have since been adopted by the IASP. The criteria require there to be<unk>  as well as a history and clinical evidence of Sensory, Vasomotor, Sudomotor and Motor or Trophic changes. It is also stated that it is a diagnosis of exclusion. To make a clinical diagnosis all four of the following criteria must be met: # Continuing<unk> , which is disproportionate to any inciting event # Must report at least one symptom in three of the four following categories.. #* Sensory: Reports of hyperesthesia #* Vasomotor: Reports of temperature asymmetry and/or skin color changes and/or skin color asymmetry #* Sudomotor/Edema: Reports of edema and/or sweating changes and/or sweating asymmetry #* Motor/Trophic: Reports of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nail, skin) # Must display at least one sign at time of evaluation in two or more of the following categories #* Sensory: Evidence of hyperalgesia (to pinprick) and/or allodynia (to light touch and/or temperature sensation and/or deep somatic pressure and/or joint movement) #* Vasomotor: Evidence of temperature asymmetry (>1 °C) and/or skin color changes and/or asymmetry #* Sudomotor/Edema: Evidence of edema and/or sweating changes and/or sweating asymmetry #* Motor/Trophic: Evidence of decreased range of motion and/or motor dysfunction (weakness, tremor, dystonia) and/or trophic changes (hair, nail, skin) # There is no other diagnosis that better explains the signs and symptoms Diagnostic adjuncts No specific test is available for<unk> , which is diagnosed primarily through observation of the symptoms. However, thermography, sweat testing, X-rays, electrodiagnostics, and sympathetic blocks can be used to build up a picture of the disorder. Diagnosis is complicated by the fact that some patients improve without treatment. A delay in diagnosis and/or treatment for this<unk>  can result in severe physical and psychological problems. Early recognition and prompt treatment provide the greatest opportunity for recovery. Thermography Presently, established empirical evidence suggests against thermography's efficacy as a reliable tool for diagnosing<unk> . Although<unk>  may, in some cases, lead to measurably altered blood flow throughout an affected region, many other factors can also contribute to an altered thermographic reading, including the patient's smoking habits, use of certain skin lotions, recent physical activity, and prior history of trauma to the region. Also, not all patients diagnosed with<unk>  demonstrate such "vasomotor instability" — particularly those in the later stages of the disease. Thus, thermography alone cannot be used as conclusive evidence for—or against—a diagnosis of<unk>  and must be interpreted in light of the patient's larger medical history and prior diagnostic studies. In order to minimise the confounding influence of external factors, patients undergoing infrared thermographic testing must conform to special restrictions regarding the use of certain vasoconstrictors (namely, nicotine and caffeine), skin lotions, physical therapy, and other diagnostic procedures in the days prior to testing. Patients may also be required to discontinue certain<unk>  medications and sympathetic blockers. After a patient arrives at a thermographic laboratory, he or she is allowed to reach thermal equilibrium in a 16–20 °C, draft-free, steady-state room wearing a loose fitting cotton hospital gown for approximately twenty minutes. A technician then takes infrared images of both the patient's affected and unaffected limbs, as well as reference images of other parts of the patient's body, including his or her face, upper back, and lower back. After capturing a set of baseline images, some labs further require the patient to undergo cold-water autonomic-functional-stress-testing to evaluate the function of their autonomic nervous system's peripheral vasoconstrictor reflex. This is performed by placing a patient's unaffected limb in a cold water bath (approximately 20 °C) for five minutes while collecting images. In a normal, intact, functioning autonomic nervous system, a patient's affected extremity will become colder. Conversely, warming of an affected extremity may indicate a disruption of the body's normal thermoregulatory vasoconstrictor function, which may sometimes indicate underlying<unk> . Radiography Scintigraphy, plain radiographs, and magnetic resonance imaging may all be useful diagnostically. Patchy osteoporosis (post-traumatic osteoporosis), which may be due to disuse of the affected extremity, can be detected through X-ray imagery as early as two weeks after the onset of<unk> . A bone scan of the affected limb may detect these changes even sooner and can almost confirm the disease. Bone densitometry can also be used to detect changes in bone mineral density. It can also be used to monitor the results of treatment since bone densitometry parameters improve with treatment. Ultrasound Ultrasound-based osteodensitometry (ultrasonometry) may be potential future radiation-free technique to identify reduced bone mineral density in<unk> . Additionally, this method promises to quantify the bone architecture in the periphery of affected limbs. This method is still under experimental development. Electrodiagnostic testing Electromyography (EMG) and nerve conduction studies (NCS) are important ancillary tests in<unk>  because they are among the most reliable methods of detecting nerve injury. They can be used as one of the primary methods to distinguish between<unk>  types I and II, which differ based on evidence of actual nerve damage. EMG and NCS are also among the best tests for ruling in or out alternative diagnoses.<unk>  is a "diagnosis of exclusion", which requires that no other diagnosis can explain the patient's symptoms. This is very important to emphasise because patients otherwise can be given a wrong diagnosis of<unk>  when they actually have a treatable condition that better accounts for their symptoms. An example is severe carpal tunnel<unk>  (CTS), which can often present in a very similar way to<unk> . Unlike<unk> , CTS can often be corrected with surgery to alleviate the<unk>  and avoid permanent nerve damage and malformation. Both EMG and NCS involve some measure of discomfort. EMG involves the use of a tiny needle inserted into specific muscles to test the associated muscle and nerve function. Both EMG and NCS involve very mild shocks that in normal patients are comparable to a rubber band snapping on the skin. Although these tests can be very useful in<unk> , thorough informed consent must be obtained prior to the procedure, particularly in patients experiencing severe allodynia. In spite of the utility of the test, these patients may wish to decline the procedure to avoid discomfort. Classification * Type I, formerly known as reflex sympathetic dystrophy (RSD), Sudeck's atrophy, or algoneurodystrophy, does not exhibit demonstrable nerve lesions. As the vast majority of patients diagnosed with<unk>  have this type, it is most commonly referred to in medical literature as type I. * Type II, formerly known as causalgia, has evidence of obvious nerve damage. Despite evidence of nerve injury, the cause or the mechanisms of<unk>  type II are as unknown, as the mechanisms of type I. Patients are frequently classified into two groups based upon temperature: "warm" or "hot"<unk>  in one group and "cold"<unk>  in the other group. The majority of patients (about 70%) have the "hot" type, which is said to be an acute form of<unk> . Cold<unk>  is said to be indicative of a more chronic<unk>  and is associated with poorer McGill<unk>  Questionnaire scores, increased central nervous system involvement, and a higher prevalence of dystonia. Prognosis is not favourable for cold<unk>  patients; longitudinal studies suggest these patients have "poorer clinical<unk>  outcomes and show persistent signs of central sensitisation correlating with disease progression".
Complex regional pain syndrome
Thoracic outlet syndrome
Calpainopathy
Myofascial pain syndrome
Central pain syndrome
Nerve compression syndrome
Radiation-induced lumbar plexopathy
Polymyalgia rheumatica