2DefinitionCRPS: Complex regional Pain Syndrome, a neuropathic pain syndrome associated with sympathetic nervous system dysfunctionCRPS1: Previously known as Reflex sympathetic dystrophy, is a syndrome occurring after minor traumaCRPS 11: Causalgia, usually occurs after major nerve injury
4Pathophysiology Peripheral & Central Mechanism Proposed mech include Sensitization of small diameter polymodal C & A delta afferent fibersSensitization of central wide dynamic range neuronsAltered activity of low threshold A beta fibers
5QuestionComplex regional pain syndrome type 11 (Causalgia) is differentiated from complex regional pain synd type 1 by knowledge ofEtiologyChronicityAffected body regionType of symptomsRapidity of onset
6Answer (A)Complex regional pain syndrome type 1 is a clinical syndrome of continuous burning pain usually occurring after an injury or surgery. Pts present with variable sensory, motor, autonomic, & trophic changes. Complex regional pain syndrome type 11 exhibits the same features as complex regional pain syndrome type 1, but the etiology is damage to a major nerve.
8Diagnostic criteriaAt least 4 of the following must be present to diagnose CRPSExamination findings:Temperature / Color change.EdemaTrophic skin, hair, nail growth abnormalities.Impaired motor function.Hyperpathia / AllodyniaSudomotor changes
9Diagnostic criteria-cont- Diagnostic test resultsThree phase bone scan that is abnormal in pattern characteristic.This test is not needed if 4 or more of examination findings are present.
10Stages of Complex regional type 1 CRPS 1 is divided into 3 stagesAcuteDystrophicAtrophic
11Acute phase Pain: Localized, Severe, Burning Extremity : Warm, swollen, nail growthSkin: Dry & red, growth of hairsX-ray: NormalMech.: Could be due to increase blood supply
12Dystrophic Phase Pain: Diffuse, throbbing Extremity: Cold, Cyanotic, edematous, muscle wasting.Skin: Sweaty, thinning or loss of hairsX-ray: Reveals osteoporosisMech.: Could be due to vasoconstriction
13Atrophic Phase Pain: Less severe, may involve other extremities Extremity: Severe muscle atrophy, contracturesSkin: Glossy & atrophicX-ray: Reveals severe osteoporosis, & ankylosis of joints.Mech.: Could be due to disuse atrophy
14Physical Exam Allodynia: Perception of non noxious stimulus as painful Hyperesthesia: Increased response to mild stimulusSkin discoloration/mottlingDry glossy extremitySweatingEdemaAbnormal temperatureWeakness, tremor, Hyperkeratosis, Brittle nail
15Question Allodynia is defined as Spontaneous pain in an area or region that is anestheticPain initiated or caused by a primary lesion or dysfunction in the nervous system.An unpleasant abnormal sensation, whether spontaneous or provokedAn increased response to a stimulus that is normally painfulPain caused by a stimulus that does not normally provoke pain.
16Answer (E). The IASP has defined several pain terms. Anesthesia dolorosa: refers to spontaneous pain in an area or region that is anesthetic.Neuropathic pain: is caused by dysfuction in NS.Dysthesia :is unpleasant abnormal sensation.Hyperalgesia :is increased response to painful stimulus.Allodynia: is pain caused by a stimulus that does not normally provoke pain.
17Tests Imaging Osteoporosis or fine demineralization on xray Increased periarticular uptake in delayed bone scintigraphy
18Pathological findings Reduced thermoregulatory reflexesChanges in sudomotor neuron activityNeurogenic inflammation
19QuestionWhich of the following choices is not consistent with a limb affected by complex regional pain syndrome?Osteoporosis.Allodynia.Dermatomal distribution of painAtrophy of the involved extremity.Hyperesthesia.
22Medications First line Anticonvulsants Gabapentin up to 900 mgs PO q8 hrs.Pregabalin up to 300 mg PO q 12 hrsTricyclic antidepressants:Amitriptiline up to 150 mgs PO qhsNortriptylene: upto 150 mgs PO qhsDesipramine: upto 150 mgs PO qhs- NSAIDs: If no complications
23Second Line Other anticonvulsants Oxcarbazepine upto 600 mg PO q12 hrs Lamotrigine upto 150 mgs PO qhsShort & long acting opioids (Controversial)Alpha adrenergic blocking agentsCorticosteroids(Short term only)BiphosphonatesTopical therapies
24Interventional Regional anesthetic approaches Sympathetic blockade (local with or without steroids)Peripheral nerve blockadeIV regional analgesia (reserpine, guanethidine, bretylium)Chemical sympathetic neurolysisRadiofrequency sympathetic rhizotomyEpidural clonidineSpinal cord stimulation
26Mental Test/Behavioral Psychometric testingCounselingBehavioral modificationRelaxation therapyGroup therapySelf-hypnosisPsychotherapyMedical management of depression
27Technique for Stellate ganglion Block Pt. supine, head midline, mouth slightly open2 finger breadth or 2 cm. above clavicular head, trachea, sternocleidomastoid ms, & carotid sheath palpated at level of cricoid cartilage2 fingers press down at lat. Edge of transverse process of C6, pushing the contents of carotid sheath laterallyA in. 23 or 25 gauge B bevel needle is inserted lat to trachea after skin inf. With local anesth.Transverse of C6 encountered between 2 fingers withdraw needle 2 mm & inj 8-10 ml local
32Signs of successful block Horner’s synd.Ipsilateral nasal congestionFlushing of conjunctiva & skinTemperature increase in the ipsilateral arm & hand
33Side effects & complications Lump sensation in throatHoarseness & dysphagia due to recurrent n blockHematoma, osteitisBrachial Plexus blockPhrenic nerve blockEpidural & subarachnoid blockPneumothoraxVertebral art. Inj. Causing loss of consciousnessCardioaccelarator nerve block with hypotension
34Follow up Prognosis Some resolve with minimal management Most respond to initial conservative measureEarly aggressive treatment in those with rapid temporal changes has best results if initiated within 12 weeks of onsetPrognosis poor if pain becomes chronic with marked disability, thus emphasizing multidisciplinary approach.