Complex Regional Pain Syndrome (CRPS) is a poorly understood chronic pain condition of multifactorial origin. CRPS involves sensory, motor, and autonomic symptoms primarily affecting one extremity. The affected neuropsychological functions constitute three distinct but not independent groups: distorted body representation, deficits in lateralised spatial cognition, and impairment of non-spatially-lateralised higher cognitive functions. (Halicka et al, 2020).
In acute phase, patients experience severe burning pain with redness, warmth and swelling along with mechanical and thermal allodynia and/or hyperalgesia. Autonomic system (increased sweating) is involved in 50%of patients. In the chronic phase, the skin turns cold and bluish. Trophic changes possibly due to interruption of nerve supply which result in shiny skin and faster hair and nail growth.
CRPS primarily involves the extremities and craniofacial area involvement is not that common.
The diagnosis and treatment of CRPS are often difficult as there is no one confirmatory test and no one definitive treatment. Currently, the most widely accepted clinical diagnostic criteria are the Budapest criteria, which were developed by expert consensus. (Kessler et al, 2020)
Complex regional pain syndrome describes an array of painful conditions that are characterized by a continuing (spontaneous and/or evoked) regional pain that is seemingly disproportionate in time or degree to the usual course of any known trauma or other lesion. The pain is regional (not in a specific nerve territory or dermatome) and usually has a distal predominance of abnormal sensory, motor, sudomotor, vasomotor, and/or trophic findings. The syndrome shows variable progression over time.
To make the clinical diagnosis, the following criteria must be met:
There is no other diagnosis that better explains the signs and symptoms.
There are mostly case reports in the literature, describing burning pain and allodynia accompanied by swelling and redness on exposure to cold or stress after a traumatic event. (Kalladka et al, 2020)
The clinical presentation includes spontaneous or evoked pain, burning, shooting, throbbing, pressing and aching. The location is usually deep, and the intensity is disproportionate to the inciting event. they might be hyperalgesia, allodynia. Autonomic dysfunction might be present.
As with CRPS in other parts of the body, the signs and symptoms of CRPS in the face always start after a traumatic event, eg, a penetrating lesion on the skin of the face, tooth extraction, or surgical trauma to the craniofacial region. (Melis et al, 2002).
Goals of therapy in CRPS should be pain relief, functional restoration, and psychological stabilization, but early interventions are needed in order to achieve these objectives.
Several drugs have been used to reduce pain and to improve functional status in CRPS, despite the lack of scientific evidence supporting their use in this scenario. They include anti-inflammatory drugs, analgesics, anesthetics, anticonvulsants, antidepressants, oral muscle relaxants, corticosteroids, calcitonin, bisphosphonates, calcium channel blockers and topical agents. (Resmini et al, 2015)
Ketamine, a NMDA receptor antagonist for anesthetic, and sympathetic nerve blocks may be effective in elected cases.
The best available data show that graded motor imagery and mirror therapy may provide clinically meaningful improvements in pain and function in people with CRPS I although the quality of the supporting evidence is very low. (Smart et al, 2016)
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Richard A. Pertes, DDS, Sowmya Ananthan, DMD, MSD; ttps://moodle.rutgers.edu/pluginfile.php/191829/mod_resource…nt/12/Chapter5/Ch_5_Neuropathic_Orofacial_Pain_Disorders.html
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Smart KM, Wand BM, O'Connell NE. Physiotherapy for pain and disability in adults with complex regional pain syndrome (CRPS) types I and II. Cochrane Database Syst Rev. 2016 Feb 24;2(2):CD010853. doi: 10.1002/14651858.CD010853.pub2. PMID: 26905470; PMCID: PMC8646955.