Complex Regional Pain Syndrome (CRPS)¶

VERSION: 1.1 CREATED: February 8, 2026 REVISED: February 8, 2026 STATUS: Draft - Revised per Checker/Rebuilder Pipeline

DIAGNOSIS: Complex Regional Pain Syndrome (CRPS)

ICD-10: G90.50 (Complex regional pain syndrome I, unspecified), G90.51 (CRPS I of upper limb), G90.52 (CRPS I of lower limb), G90.59 (CRPS I, other specified site), G56.40 (Causalgia of unspecified upper limb — CRPS II), G57.70 (Causalgia of unspecified lower limb — CRPS II)

CPT CODES: 85025 (CBC), 80048 (BMP), 86140 (CRP quantitative), 86200 (CRP), 85652 (ESR), 86235 (ANA), 84443 (TSH), 82310 (Calcium total), 82607 (Vitamin B12), 78300 (Triple-phase bone scan), 77072 (Bone survey), 70553 (MRI brain without and with contrast), 73221 (MRI upper extremity), 73721 (MRI lower extremity), 73000 (Plain radiograph upper extremity), 73590 (Plain radiograph lower extremity), 95907-95913 (Nerve conduction studies, 1-13+ studies), 95903 (NCS — motor), 95904 (NCS — sensory), 95886 (Needle EMG, complete), 95860 (EMG — needle), 88305 (Skin biopsy — IENFD pathology), 96000 (Quantitative sensory testing), 95836 (Autonomic function testing — sudomotor), 64520 (Stellate ganglion block), 64530 (Lumbar sympathetic block), 64510 (Stellate ganglion block — alternate), 63650 (Spinal cord stimulator — percutaneous trial), 63685 (Spinal cord stimulator — permanent implant), 96365 (IV infusion, initial hour — ketamine), 96366 (IV infusion, additional hour)

SYNONYMS: CRPS, complex regional pain syndrome, CRPS type I, CRPS type II, CRPS type 1, CRPS type 2, CRPS-I, CRPS-II, reflex sympathetic dystrophy, RSD, causalgia, Sudeck atrophy, algodystrophy, algoneurodystrophy, sympathetically maintained pain, SMP, shoulder-hand syndrome

SCOPE: Evaluation and management of Complex Regional Pain Syndrome (CRPS) Types I and II in adults. Includes Budapest diagnostic criteria, staging, etiologic workup, pharmacologic management (neuropathic pain agents, bisphosphonates, corticosteroids), interventional procedures (sympathetic blocks, spinal cord stimulation), and rehabilitation (graded motor imagery, mirror therapy). Covers ED acute pain management, inpatient evaluation, outpatient chronic management, and ICU-level ketamine infusion protocols. Excludes other chronic pain syndromes unless part of differential.

DEFINITIONS: - CRPS Type I (Reflex Sympathetic Dystrophy): Regional pain syndrome occurring after an inciting noxious event (fracture, surgery, immobilization) without a definable nerve lesion; disproportionate to inciting event - CRPS Type II (Causalgia): Regional pain syndrome with a definable nerve lesion confirmed by electrodiagnostic studies or imaging - Budapest Criteria: Validated clinical diagnostic criteria requiring symptoms in 3 or more categories and signs in 2 or more categories from: sensory, vasomotor, sudomotor/edema, and motor/trophic domains - Sympathetically Maintained Pain (SMP): Pain component mediated by sympathetic efferent activity; responsive to sympathetic blockade - Sympathetically Independent Pain (SIP): Pain component that persists despite sympathetic blockade - Allodynia: Pain from a stimulus that does not normally provoke pain (e.g., light touch) - Hyperalgesia: Increased pain from a stimulus that normally provokes pain - Budapest Criteria Categories: (1) Sensory — allodynia, hyperalgesia, hyperesthesia; (2) Vasomotor — temperature asymmetry >1°C, skin color changes; (3) Sudomotor/edema — edema, sweating changes, sweating asymmetry; (4) Motor/trophic — decreased ROM, weakness, tremor, dystonia, trophic changes (hair, nail, skin)

PRIORITY KEY: STAT = Immediate | URGENT = Within hours | ROUTINE = Standard | EXT = Extended/atypical cases | - = Not applicable to this setting

1. LABORATORY WORKUP¶

1A. Core Labs (All Patients)¶

Test	ED	HOSP	OPD	ICU	Rationale	Target Finding
CBC with differential (CPT 85025)	STAT	ROUTINE	ROUTINE	STAT	Baseline; exclude infection or hematologic cause of pain	Normal
BMP (CPT 80048)	STAT	ROUTINE	ROUTINE	STAT	Electrolytes, renal function; baseline before bisphosphonate or NSAID use; required before ketamine infusion	Normal
ESR (CPT 85652)	ROUTINE	ROUTINE	ROUTINE	-	Exclude inflammatory or infectious etiology	<20 mm/hr
CRP (CPT 86200)	ROUTINE	ROUTINE	ROUTINE	-	Exclude infection, inflammatory arthritis, or osteomyelitis	<0.5 mg/dL
Calcium, phosphorus, vitamin D (25-OH)	-	ROUTINE	ROUTINE	-	Baseline before bisphosphonate therapy; exclude metabolic bone disease	Normal calcium; vitamin D >30 ng/mL
TSH (CPT 84443)	-	ROUTINE	ROUTINE	-	Thyroid dysfunction can mimic or exacerbate pain/autonomic symptoms	0.4-4.0 mIU/L
Magnesium	STAT	ROUTINE	ROUTINE	STAT	Baseline for ketamine infusion; hypomagnesemia exacerbates pain	1.7-2.2 mg/dL

1B. Extended Labs (Based on Clinical Suspicion)¶

Test	ED	HOSP	OPD	ICU	Rationale	Target Finding
ANA (CPT 86235)	-	ROUTINE	ROUTINE	-	Exclude autoimmune/connective tissue disease as cause of pain and vasomotor changes	Negative
Uric acid	-	EXT	EXT	-	Exclude gout if joint involvement suspected	Normal
HbA1c / fasting glucose	-	ROUTINE	ROUTINE	-	Diabetes as risk factor for CRPS-II (neuropathic component)	HbA1c <5.7%; fasting glucose <100 mg/dL
Serum protein electrophoresis (SPEP)	-	EXT	EXT	-	Exclude paraproteinemia if atypical neuropathy suspected	No monoclonal protein
Hepatic function panel	-	ROUTINE	ROUTINE	-	Baseline before chronic analgesic or bisphosphonate therapy	Normal

1C. Rare/Specialized Labs¶

Test	ED	HOSP	OPD	ICU	Rationale	Target Finding
Complement C3/C4	-	-	EXT	-	If vasculitis or autoimmune etiology suspected	Normal
Paraneoplastic antibody panel	-	-	EXT	-	If atypical presentation raises concern for paraneoplastic syndrome	Negative
Catecholamines (plasma or urine)	-	-	EXT	-	If pheochromocytoma or sympathetic hyperactivity considered	Normal

2. DIAGNOSTIC IMAGING & STUDIES¶

2A. Essential Imaging (First-Line)¶

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
Plain radiographs of affected limb (CPT 73000/73590)	ROUTINE	ROUTINE	ROUTINE	-	Initial evaluation	Patchy osteopenia (Sudeck atrophy) in established CRPS; exclude fracture	None
Triple-phase bone scan (CPT 78300)	-	ROUTINE	ROUTINE	-	Within first 6 months for highest sensitivity	Increased periarticular uptake in delayed phase; sensitivity 80-96% in early CRPS	Pregnancy
MRI of affected extremity (CPT 73221/73721)	-	ROUTINE	ROUTINE	-	When diagnosis uncertain or to exclude alternate pathology	Bone marrow edema, soft tissue edema, skin thickening; exclude tumor, infection, AVN	MRI-incompatible implants

2B. Extended Imaging & Diagnostic Studies¶

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
Nerve conduction studies / EMG (CPT 95903/95904/95860)	-	ROUTINE	ROUTINE	-	If CRPS-II suspected or to differentiate from peripheral neuropathy	Define nerve lesion for CRPS-II; normal in CRPS-I	Anticoagulation (relative for needle EMG)
Infrared thermography	-	EXT	ROUTINE	-	Supportive; temperature asymmetry >1°C	Temperature difference >1°C between affected and unaffected limb	None
Diagnostic sympathetic nerve block (stellate ganglion or lumbar sympathetic) (CPT 64510/64520)	-	ROUTINE	ROUTINE	-	To determine sympathetically maintained vs independent pain	>50% pain relief supports SMP component	Coagulopathy, local infection, patient refusal

2C. Rare/Specialized Studies¶

Study	ED	HOSP	OPD	ICU	Timing	Target Finding	Contraindications
Quantitative sensory testing (QST) (CPT 96000)	-	-	ROUTINE	-	Outpatient; quantify sensory thresholds	Altered thermal and vibratory thresholds in affected limb	Requires patient cooperation
Sudomotor function testing (QSART) (CPT 95836)	-	-	ROUTINE	-	Outpatient; assess autonomic (sudomotor) dysfunction	Asymmetric sweat output in affected limb	None
Skin biopsy for intraepidermal nerve fiber density (IENFD) (CPT 88305)	-	-	EXT	-	If CRPS-II suspected or small fiber neuropathy overlap	Reduced IENFD in affected limb	Anticoagulation (relative), local infection
Laser Doppler flowmetry	-	-	EXT	-	Research/specialized centers; assess microvascular flow	Asymmetric blood flow	None
DEXA scan	-	-	EXT	-	If bisphosphonate considered; evaluate bone density	Document osteopenia/osteoporosis	None

3. TREATMENT¶

3A. Acute/Emergent Management (Pain Crisis)¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
IV ketamine (subanesthetic)	IV	Acute CRPS pain crisis; refractory severe pain	0.1-0.3 mg/kg/hr :: IV :: continuous :: Start 0.1 mg/kg/hr; titrate by 0.05 mg/kg/hr q30min; max 0.3 mg/kg/hr; infusion duration 4-8 hours	Uncontrolled HTN, psychosis, raised ICP, pregnancy	BP, HR, SpO2, dissociative symptoms q15-30min during infusion	URGENT	ROUTINE	-	ROUTINE
Prednisone (corticosteroid burst)	PO	Early CRPS (<3 months); acute inflammatory phase	40 mg/day :: PO :: daily :: 40 mg/day x 2 weeks, then taper by 10 mg/week over 2 weeks; total 4-week course	Active infection, uncontrolled diabetes, GI ulcer	Blood glucose, BP, mood, GI symptoms	-	ROUTINE	ROUTINE	-
Ketorolac	IV/IM	Acute pain management; short-term use	15-30 mg :: IV :: q6h :: 15-30 mg IV q6h; max 5 days	Renal impairment, GI bleeding, coagulopathy	Renal function, GI symptoms	STAT	ROUTINE	-	ROUTINE
Lidocaine IV infusion	IV	Refractory acute CRPS pain; neuropathic pain crisis	1-5 mg/kg :: IV :: once :: 1-5 mg/kg over 30-60 minutes; cardiac monitoring required	Cardiac arrhythmia, heart block, hepatic failure, allergy to amides	Continuous ECG, BP, neurologic status for toxicity (perioral numbness, tinnitus)	-	ROUTINE	-	ROUTINE
Morphine	IV	Severe acute pain crisis unresponsive to non-opioid measures	2-4 mg :: IV :: q2-4h PRN :: 2-4 mg IV q2-4h PRN; titrate to pain control; avoid long-term opioid use in CRPS	Respiratory depression, paralytic ileus, known opioid allergy	Respiratory rate, sedation, pain scores; naloxone at bedside	URGENT	ROUTINE	-	ROUTINE

3B. First-Line Pharmacotherapy¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Gabapentin	PO	Neuropathic pain; first-line for CRPS pain	300 mg qHS; 300 mg TID; 600 mg TID :: PO :: TID :: Start 300 mg qHS; titrate by 300 mg q3-7d; target 1800-3600 mg/day in 3 divided doses	Severe renal impairment (dose adjust)	Sedation, dizziness, peripheral edema; adjust dose for CrCl <60	ROUTINE	ROUTINE	ROUTINE	-
Pregabalin	PO	Neuropathic pain; alternative to gabapentin	75 mg BID; 150 mg BID; 300 mg BID :: PO :: BID :: Start 75 mg BID; titrate by 75 mg q3-7d; max 600 mg/day	Severe renal impairment (dose adjust)	Sedation, dizziness, weight gain, peripheral edema	ROUTINE	ROUTINE	ROUTINE	-
Amitriptyline	PO	Neuropathic pain; sleep disruption from pain	10 mg qHS; 25 mg qHS; 75 mg qHS :: PO :: qHS :: Start 10 mg qHS; titrate by 10-25 mg q1-2 weeks; max 75-150 mg/day	Cardiac arrhythmia, recent MI, MAOIs, urinary retention, narrow-angle glaucoma	ECG at baseline if >40 yo or cardiac risk; anticholinergic effects; sedation	ROUTINE	ROUTINE	ROUTINE	-
Nortriptyline	PO	Neuropathic pain; better tolerated than amitriptyline	10 mg qHS; 25 mg qHS; 75 mg qHS :: PO :: qHS :: Start 10 mg qHS; titrate by 10-25 mg q1-2 weeks; max 150 mg/day	Cardiac arrhythmia, recent MI, MAOIs, urinary retention, narrow-angle glaucoma	ECG at baseline if >40 yo or cardiac risk; anticholinergic effects (less than amitriptyline); sedation	ROUTINE	ROUTINE	ROUTINE	-
Duloxetine	PO	Neuropathic pain; comorbid depression or anxiety	30 mg daily; 60 mg daily :: PO :: daily :: Start 30 mg daily x 1 week; increase to 60 mg daily; max 120 mg/day	Severe hepatic impairment, MAOIs, uncontrolled narrow-angle glaucoma	Hepatic function, BP, serotonergic effects; taper when discontinuing	ROUTINE	ROUTINE	ROUTINE	-
Topical lidocaine 5% patch	Topical	Localized allodynia; adjunctive pain relief	1-3 patches :: Topical :: q12h :: Apply up to 3 patches to affected area; 12 hours on / 12 hours off	Allergy to amide anesthetics	Skin irritation at application site	ROUTINE	ROUTINE	ROUTINE	-
Topical capsaicin 8% patch	Topical	Localized CRPS pain; desensitization	1 patch :: Topical :: q3 months :: Single 60-minute application to affected area; may repeat q3 months; apply in clinic setting with pretreatment	Open wounds, broken skin	Pain during application (pretreat with topical anesthetic); skin erythema	-	-	ROUTINE	-

3C. Second-Line/Refractory Pharmacotherapy¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Alendronate	PO	CRPS with bone pain, osteopenia; strong evidence for pain reduction	40 mg/day :: PO :: daily :: 40 mg/day x 8 weeks; take on empty stomach with full glass of water; remain upright 30 min	Esophageal disorders, hypocalcemia, CrCl <35	Calcium, vitamin D levels; GI symptoms; renal function	-	-	ROUTINE	-
Pamidronate (IV bisphosphonate)	IV	CRPS with significant bone involvement; oral bisphosphonate intolerant	60 mg :: IV :: q4 weeks x 3 :: 60 mg IV infusion over 2-4 hours q4 weeks x 3 doses	Hypocalcemia, severe renal impairment (CrCl <30)	Calcium, creatinine, phosphorus; flu-like symptoms post-infusion; osteonecrosis of jaw (rare)	-	ROUTINE	ROUTINE	-
Zoledronic acid (IV bisphosphonate)	IV	CRPS; alternative IV bisphosphonate	5 mg :: IV :: once :: 5 mg IV over 15 minutes; single dose	Hypocalcemia, CrCl <35	Calcium, creatinine; flu-like symptoms 1-3 days post-infusion; dental evaluation before treatment	-	ROUTINE	ROUTINE	-
Baclofen	PO	CRPS-related dystonia or muscle spasm	5 mg TID; 10 mg TID; 20 mg TID :: PO :: TID :: Start 5 mg TID; titrate by 5 mg/dose q3-5d; max 80 mg/day	Withdrawal seizures if abrupt discontinuation	Sedation, weakness; taper gradually when discontinuing	-	ROUTINE	ROUTINE	-
Clonidine transdermal patch	Transdermal	Sympathetically maintained pain component; adjunctive	0.1 mg/day; 0.2 mg/day :: Transdermal :: weekly :: Start 0.1 mg/day patch; titrate to 0.2 mg/day after 1-2 weeks	Bradycardia, hypotension	BP, HR; rebound hypertension if abruptly removed	-	ROUTINE	ROUTINE	-
Calcitonin (nasal)	Intranasal	CRPS pain; bone-related pain	200 IU :: Intranasal :: daily :: 200 IU intranasal daily; alternate nostrils	Hypersensitivity to salmon calcitonin	Rhinitis, nasal irritation; limited long-term efficacy data	-	-	ROUTINE	-
IV ketamine infusion (multi-day)	IV	Refractory CRPS; inpatient protocol	0.1-0.35 mg/kg/hr :: IV :: continuous :: 0.1-0.35 mg/kg/hr continuous infusion over 4-14 days; requires dedicated pain or ICU setting	Uncontrolled HTN, psychosis, raised ICP, pregnancy, hepatic failure	Continuous cardiac monitoring, BP, SpO2, hepatic function, dissociative symptoms, bladder function	-	ROUTINE	-	ROUTINE
Memantine	PO	NMDA antagonist; adjunctive for refractory neuropathic pain	5 mg daily; 10 mg BID :: PO :: daily then BID :: Start 5 mg daily; increase by 5 mg/week; target 10 mg BID; max 20 mg/day	Severe renal impairment	Dizziness, headache, confusion; adjust dose for renal function	-	-	EXT	-
Naproxen	PO	Mild-moderate CRPS pain; anti-inflammatory adjunct	250 mg BID; 500 mg BID :: PO :: BID :: Start 250 mg BID; increase to 500 mg BID if tolerated; max 1000 mg/day	GI bleeding, renal impairment, aspirin-exacerbated respiratory disease	GI symptoms, renal function, BP; avoid long-term use	ROUTINE	ROUTINE	ROUTINE	-

3D. Interventional/Procedural Therapies¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Stellate ganglion block (CPT 64510)	Injection	Upper extremity CRPS; diagnostic and therapeutic sympathetic blockade	N/A :: Injection :: series :: Fluoroscopic or ultrasound-guided; series of 3-6 blocks at 1-2 week intervals	Coagulopathy, local infection, contralateral pneumothorax, contralateral vocal cord paralysis	Horner syndrome (expected); BP, respiratory status; hoarseness; pneumothorax risk	-	ROUTINE	ROUTINE	-
Lumbar sympathetic block (CPT 64520)	Injection	Lower extremity CRPS; diagnostic and therapeutic sympathetic blockade	N/A :: Injection :: series :: Fluoroscopic-guided; series of 3-6 blocks at 1-2 week intervals	Coagulopathy, local infection	BP, temperature change in affected limb (expected warmth); back pain	-	ROUTINE	ROUTINE	-
Spinal cord stimulation (SCS) — trial (CPT 63650)	Implant	CRPS refractory to conservative management >=6 months; >50% pain relief with trial	N/A :: Implant :: trial :: Percutaneous trial lead placement; 5-7 day trial period; success = >=50% pain relief and functional improvement	Active infection, coagulopathy, inability to undergo MRI (varies by device), psychiatric instability	Pain scores, functional assessment during trial; wound site	-	ROUTINE	ROUTINE	-
Spinal cord stimulation (SCS) — permanent implant (CPT 63685)	Implant	Successful SCS trial (>=50% pain relief)	N/A :: Implant :: permanent :: Permanent pulse generator and lead placement; programming optimization over weeks	Active infection, failed trial, psychiatric instability, unrealistic expectations	Device function, pain scores, wound healing; ongoing reprogramming	-	ROUTINE	ROUTINE	-
Dorsal root ganglion (DRG) stimulation	Implant	CRPS especially involving foot or focal distribution; alternative to traditional SCS	N/A :: Implant :: permanent :: Trial followed by permanent implant if successful; targets specific DRG level	Active infection, coagulopathy, inability to undergo MRI (varies by device), psychiatric instability	Pain scores, paresthesia coverage of affected area, wound site	-	ROUTINE	ROUTINE	-
Intrathecal baclofen pump	Implant	CRPS-related dystonia refractory to oral baclofen	N/A :: Intrathecal :: continuous :: Trial with intrathecal bolus; if successful, pump implantation; typical dose 50-800 mcg/day	Active infection, CSF obstruction	Baclofen withdrawal (life-threatening if pump malfunction); dystonia response; pump refills q1-3 months	-	ROUTINE	ROUTINE	-
IVIG (intravenous immunoglobulin)	IV	CRPS with suspected autoimmune/inflammatory component; refractory cases	0.5 g/kg/day :: IV :: daily x 5 :: 0.5 g/kg/day x 5 days; may repeat monthly based on response	IgA deficiency with anti-IgA antibodies, severe renal impairment	Renal function, headache (aseptic meningitis), thrombotic events, infusion reactions; premedicate with acetaminophen and diphenhydramine	-	ROUTINE	EXT	-

3E. Rehabilitation Therapies¶

Treatment	Route	Indication	Dosing	Contraindications	Monitoring	ED	HOSP	OPD	ICU
Graded motor imagery (GMI)	PT/OT	All CRPS patients; central desensitization program	N/A :: PT/OT :: daily :: Three-stage protocol: (1) laterality recognition, (2) imagined movements, (3) mirror therapy; 10-15 min/session progressing over weeks	None	Pain levels during sessions; functional progress	-	ROUTINE	ROUTINE	-
Mirror therapy	PT/OT	CRPS of extremity; cortical reorganization	N/A :: PT/OT :: daily :: 15-30 min daily; move unaffected limb while watching mirror reflection; brain perceives affected limb moving	None (may increase pain initially — titrate)	Pain response; functional improvement	-	ROUTINE	ROUTINE	-
Desensitization program	PT/OT	Allodynia; tactile hypersensitivity	N/A :: PT/OT :: daily :: Progressive exposure to textures (silk, cotton, terry cloth, denim); graded from least to most stimulating	Severe open wounds	Allodynia severity; tolerance progression	-	ROUTINE	ROUTINE	-
Stress loading (scrubbing and carrying)	PT/OT	Upper extremity CRPS; active loading without joint movement	N/A :: PT/OT :: 3x daily :: Scrubbing: affected hand on brush, body weight through arm; Carrying: weighted bag 1-5 lbs progressing; 3 sessions/day, 3 min each	Fracture, open wound	Pain levels; edema; functional ROM	-	ROUTINE	ROUTINE	-
Aquatic therapy	PT	CRPS; weight-bearing difficulty; edema management	N/A :: PT :: 2-3x/week :: Warm water pool (92-96F); active ROM, progressive weight bearing, desensitization in water; 30-45 min sessions	Open wounds, active infection, cardiac instability	Pain levels, edema, ROM, functional progress	-	-	ROUTINE	-
Occupational therapy — functional retraining	OT	CRPS; ADL restoration and limb reintegration	N/A :: OT :: 2-3x/week :: Task-specific training; splinting as needed; activity pacing; ergonomic adaptation	None	Functional milestones; pain-contingent vs time-contingent activity	-	ROUTINE	ROUTINE	-

4. OTHER RECOMMENDATIONS¶

4A. Referrals & Consults¶

Recommendation	ED	HOSP	OPD	ICU	Indication
Pain medicine / Pain management	URGENT	ROUTINE	ROUTINE	URGENT	All CRPS patients; coordinate multimodal therapy and interventional procedures
Physical therapy (CRPS-experienced)	-	ROUTINE	ROUTINE	-	All CRPS patients; graded motor imagery, desensitization, functional restoration
Occupational therapy	-	ROUTINE	ROUTINE	-	Upper extremity CRPS; ADL retraining, splinting, functional adaptation
Psychology / Psychiatry (pain-focused CBT)	-	ROUTINE	ROUTINE	-	Cognitive behavioral therapy for pain; anxiety/depression management; catastrophizing reduction
Neurology	ROUTINE	ROUTINE	ROUTINE	-	CRPS-II evaluation; nerve lesion localization; atypical presentations; diagnostic confirmation
Orthopedic surgery	-	EXT	EXT	-	If underlying fracture/contracture management needed; avoid unnecessary surgery on affected limb
Vascular surgery	-	EXT	EXT	-	If vascular insufficiency must be excluded
Interventional radiology / Anesthesia (pain procedures)	-	ROUTINE	ROUTINE	-	Sympathetic blocks, SCS trial/implant, intrathecal pump
Sleep medicine	-	-	ROUTINE	-	Persistent sleep disruption despite analgesic optimization; comorbid insomnia assessment
Physiatry / Rehabilitation medicine	-	ROUTINE	ROUTINE	-	Comprehensive rehabilitation coordination; functional restoration program design

4B. Patient/Family Instructions¶

Recommendation	Rationale	ED	HOSP	OPD
Educate on CRPS as a real, treatable neurological condition	Combat stigma; improve treatment engagement; reduce catastrophizing	ROUTINE	ROUTINE	ROUTINE
Active use of affected limb encouraged within pain tolerance	Disuse leads to worsening dystrophy, contracture, and central sensitization	ROUTINE	ROUTINE	ROUTINE
Home mirror therapy and GMI exercises daily	Cortical reorganization requires consistent daily practice for efficacy	-	ROUTINE	ROUTINE
Avoid immobilization of affected limb (no slings, casts unless fracture)	Immobilization worsens CRPS; evidence for harm from prolonged rest	ROUTINE	ROUTINE	ROUTINE
Apply warm or cool packs per patient preference to affected area	Symptom relief; patient-directed (some prefer warmth, others cold)	ROUTINE	ROUTINE	ROUTINE
Report new weakness, spreading pain to other limbs, color changes, skin breakdown, or worsening pain promptly	Early detection of disease progression, spread, or complications	ROUTINE	ROUTINE	ROUTINE
Avoid surgical procedures on the affected limb unless absolutely necessary	Surgery on CRPS-affected limb can cause flare or spread; preoperative sympathetic block recommended if surgery unavoidable	ROUTINE	ROUTINE	ROUTINE
Keep a pain diary tracking daily pain levels, triggers, sleep, and functional activities	Facilitates treatment titration and objective progress monitoring at follow-up visits	-	ROUTINE	ROUTINE

4C. Lifestyle & Prevention¶

Recommendation	Rationale	ED	HOSP	OPD
Vitamin C 500 mg daily after fracture or surgery	Evidence supports prophylactic vitamin C (500 mg/day x 50 days) to reduce CRPS incidence after wrist fracture	ROUTINE	ROUTINE	ROUTINE
Early mobilization after fracture or surgery	Prolonged immobilization is a known risk factor for CRPS development	ROUTINE	ROUTINE	ROUTINE
Stress management and relaxation techniques (mindfulness, paced breathing, progressive muscle relaxation)	Psychological stress exacerbates CRPS symptoms and central sensitization	-	ROUTINE	ROUTINE
Sleep hygiene optimization	Poor sleep amplifies central sensitization and pain perception	-	ROUTINE	ROUTINE
Smoking cessation counseling	Smoking impairs microvascular flow and wound healing; worsens CRPS outcomes	-	ROUTINE	ROUTINE
Regular low-impact aerobic exercise (walking, cycling, swimming)	General conditioning, mood improvement, pain modulation via endorphin release	-	-	ROUTINE
Ergonomic workplace and home adaptations	Reduce repetitive strain on affected limb; activity modification to promote function without overload	-	ROUTINE	ROUTINE

5. DIFFERENTIAL DIAGNOSIS¶

Alternative Diagnosis	Key Distinguishing Features	Tests to Differentiate
Peripheral neuropathy (diabetic, idiopathic)	Symmetric stocking-glove distribution; no vasomotor or sudomotor signs; no edema; gradual onset	NCS/EMG (abnormal); HbA1c; no temperature asymmetry
Deep vein thrombosis (DVT)	Unilateral limb swelling and pain; risk factors (immobility, surgery, malignancy); no allodynia or trophic changes	D-dimer; compression ultrasound; no vasomotor color changes
Cellulitis / Soft tissue infection	Erythema, warmth, fever; WBC elevated; responds to antibiotics; no allodynia or motor/trophic signs	CBC with left shift; blood cultures; imaging if abscess suspected
Raynaud phenomenon	Episodic digital color changes (white-blue-red); triggered by cold or stress; bilateral; no pain disproportionate to findings	History of triphasic color changes; cold provocation; nailfold capillaroscopy; ANA
Peripheral vascular disease / Arterial insufficiency	Claudication; diminished pulses; ABI <0.9; trophic changes in vascular distribution; no allodynia	ABI; arterial duplex ultrasound; CTA/MRA
Fracture (occult)	Localized pain and swelling after trauma; point tenderness; no vasomotor asymmetry or sudomotor changes	Plain radiographs; CT or MRI if radiographs negative; bone scan
Tendinopathy / Overuse injury	Pain localized to tendon; worsened by specific motion; no vasomotor, sudomotor, or trophic changes	Examination; ultrasound or MRI of tendon; no diffuse limb changes
Inflammatory arthritis (RA, gout, psoriatic)	Joint-focused swelling and pain; systemic inflammatory markers elevated; polyarticular in RA	RF, anti-CCP, uric acid; joint aspiration; radiographs showing erosions
Malingering / Factitious disorder	Inconsistent examination findings; secondary gain; symptom magnification without objective autonomic signs	Objective autonomic testing (thermography, QSART) shows no asymmetry; psychological evaluation
Erythromelalgia	Episodic burning pain, erythema, warmth in distal extremities; bilateral; relieved by cooling; no edema or trophic changes	History of episodic symptoms; relief with cooling; genetic testing (SCN9A); no bone scan changes

6. MONITORING PARAMETERS¶

Parameter	Frequency	Target/Threshold	Action if Abnormal	ED	HOSP	OPD	ICU
Pain scores (NRS 0-10)	Every encounter	Trend toward reduction; goal NRS <4 or >=30% improvement	Adjust analgesic regimen; consider interventional therapy	STAT	Daily	Every visit	STAT
Limb temperature measurement (infrared)	Every encounter	Asymmetry <1C between limbs	Vasomotor changes worsening: escalate treatment	-	Daily	Every visit	-
Edema measurement (circumference)	Weekly to monthly	Decreasing edema trend	Compression therapy; elevation; medication adjustment	-	Weekly	Monthly	-
Range of motion (goniometry)	Monthly	Progressive improvement toward baseline	Intensify PT/OT; evaluate for contracture	-	Weekly	Monthly	-
Bone density (DEXA or radiographs)	Every 6-12 months	Stable or improving bone density	Initiate bisphosphonate if progressive osteopenia	-	-	Every 6-12 months	-
Renal function (creatinine, eGFR)	Before and during bisphosphonate therapy	eGFR >35 for bisphosphonates	Hold bisphosphonate if renal function declines	-	ROUTINE	q3-6 months	ROUTINE
Calcium, vitamin D	Before and during bisphosphonate therapy	Calcium normal; vitamin D >30 ng/mL	Supplement calcium and vitamin D before bisphosphonate initiation	-	ROUTINE	q3-6 months	-
Hepatic function	Baseline and q6 months if on chronic medications	Normal ALT/AST	Dose adjust or discontinue hepatotoxic medications	-	ROUTINE	q6 months	-
ECG	Baseline for tricyclic antidepressants	Normal QTc; no conduction abnormality	Do not initiate or discontinue TCA if QTc prolonged	ROUTINE	ROUTINE	Baseline	ROUTINE
SCS device function	Post-implant ongoing	Adequate paresthesia coverage; >=50% pain relief maintained	Reprogram device; evaluate for lead migration	-	Post-op	q3-6 months	-
Psychological assessment (depression, anxiety, catastrophizing)	Baseline and q3-6 months	Stable or improving mood; reduced catastrophizing	Psychology referral; medication adjustment	-	ROUTINE	q3-6 months	-
Ketamine infusion monitoring (BP, HR, SpO2, dissociation)	Continuous during infusion	BP <180/100; HR <120; SpO2 >95%; no severe dissociation	Reduce infusion rate or discontinue; administer midazolam for severe dissociation	STAT	Continuous	-	Continuous

7. DISPOSITION CRITERIA¶

Disposition	Criteria
Discharge from ED	Mild-moderate pain controlled with oral analgesics; no acute compartment syndrome; follow-up with pain medicine or neurology arranged within 1-2 weeks; able to perform basic self-care
Admit to hospital	Severe pain crisis unresponsive to outpatient management; need for IV ketamine infusion; need for IV bisphosphonate infusion; new-onset CRPS with diagnostic uncertainty requiring expedited workup; acute functional decline
ICU admission	Ketamine infusion requiring continuous cardiac monitoring; hemodynamic instability; respiratory concerns during ketamine infusion; multi-day high-dose ketamine protocol
Transfer to pain center	Refractory CRPS requiring multidisciplinary inpatient pain rehabilitation; SCS trial/implant evaluation; intrathecal pump evaluation
Outpatient follow-up — Pain medicine	All CRPS patients for ongoing multimodal management; interventional procedure scheduling; every 2-4 weeks during active treatment, then q1-3 months when stable
Outpatient follow-up — Neurology	CRPS-II patients; nerve lesion characterization and management; atypical presentations
Outpatient follow-up — PT/OT	All CRPS patients; 2-3x/week initially for GMI, mirror therapy, desensitization, functional restoration
Outpatient follow-up — Psychology	All CRPS patients; pain coping, CBT, catastrophizing reduction; q1-2 weeks initially

8. EVIDENCE & REFERENCES¶

Recommendation	Evidence Level	Source
Budapest criteria for clinical diagnosis of CRPS	Validated diagnostic criteria; sensitivity 0.99, specificity 0.68	Harden et al. Pain 2010
Comprehensive CRPS pathophysiology and management review	Expert review	Bruehl S. BMJ 2015
CRPS pathophysiology, diagnosis, and treatment overview	Expert review	Birklein et al. Neurology 2015
Bisphosphonates (alendronate 40 mg/day x 8 weeks) for CRPS pain	Level I (RCT); significant pain reduction vs placebo	Varenna et al. Rheumatology 2013
IV pamidronate for CRPS pain	Level I (RCT)	Robinson et al. Pain Medicine 2004
Spinal cord stimulation for CRPS; long-term outcomes	Level I-II; significant pain reduction; practice guidelines	Deer et al. Neuromodulation 2017
DRG stimulation superior to traditional SCS for CRPS (ACCURATE trial)	Level I (RCT)	Deer et al. Pain 2017
IV ketamine for CRPS pain (subanesthetic infusion)	Level I (RCT); significant short-term pain reduction	Sigtermans et al. Pain 2009
Corticosteroids for early CRPS	Level II; moderate evidence for acute phase	Kalita et al. Pain Physician 2016
Vitamin C 500 mg/day for CRPS prophylaxis after wrist fracture	Level I (RCT); reduced CRPS incidence	Zollinger et al. J Bone Joint Surg Am 2007
Mirror therapy and graded motor imagery for CRPS	Level II; RCTs support efficacy	Moseley GL. Neurology 2006
Guidelines for CRPS interventional management	Evidence-based consensus guidelines	Harden et al. Pain Medicine 2013

NOTES¶

CRPS is a clinical diagnosis; no single laboratory test or imaging study confirms the diagnosis — Budapest criteria are the accepted standard
Budapest criteria require: >=1 symptom in 3 of 4 categories AND >=1 sign in 2 of 4 categories (sensory, vasomotor, sudomotor/edema, motor/trophic) AND no better explanation
CRPS Type I (no nerve lesion) accounts for ~90% of cases; Type II (definable nerve lesion) accounts for ~10%
Historical staging (Acute/Warm -> Dystrophic/Mixed -> Atrophic/Cold) is controversial and not consistently observed; many patients do not progress linearly
Early aggressive treatment (within 3-6 months of onset) yields significantly better outcomes; delays worsen prognosis
Bisphosphonates have among the strongest RCT evidence for CRPS pain reduction and should not be overlooked
Multidisciplinary approach (pain medicine, PT/OT, psychology) is essential; no single intervention is sufficient
Avoid immobilization; it worsens CRPS — early mobilization is a core treatment principle
SCS is FDA-approved for CRPS and has Level I evidence; DRG stimulation may be superior for focal CRPS
IV ketamine should be administered in monitored settings only; outpatient infusion centers may be appropriate for experienced patients
Surgery on the affected limb can trigger CRPS flare or spread; preoperative sympathetic block may mitigate risk
Recurrence/spread to other limbs occurs in approximately 7-10% of patients

CHANGE LOG¶

v1.1 (February 8, 2026) - Added ICU to frontmatter setting field (was missing) - Updated VERSION to 1.1 and STATUS to reflect Checker/Rebuilder revision - Updated SCOPE to mention ICU-level ketamine protocols - Section 1A: Added ICU coverage (STAT) for CBC and BMP (needed before ketamine infusion); added Magnesium as core lab for ketamine baseline - Section 3A: Added Ketorolac ICU coverage (ROUTINE); added Morphine as acute pain option with safety guardrails - Section 3B: Fixed all empty frequency fields in structured dosing (gabapentin TID, pregabalin BID, amitriptyline qHS, nortriptyline qHS, duloxetine daily, topical lidocaine q12h, topical capsaicin q3 months) - Section 3B: Added ED coverage (ROUTINE) for all first-line oral medications — patients may present on these or need initiation - Section 3B: Fixed Nortriptyline cross-reference — replaced "Same as amitriptyline" with fully self-contained contraindications and monitoring (C1 fix) - Section 3C: Added frequency fields for baclofen (TID), memantine (daily then BID), clonidine (weekly); added Naproxen as oral NSAID option - Section 3C: Upgraded clonidine from OPD-only to include HOSP coverage - Section 4A: Added Neurology ED coverage (ROUTINE) for diagnostic confirmation; added Sleep medicine referral; added Physiatry/Rehabilitation medicine referral; total referrals now 10 - Section 4B: Expanded ED coverage for patient instructions (active limb use, surgical avoidance, return precautions); added pain diary instruction; total instructions now 8 - Section 4C: Added ergonomic workplace/home adaptations; expanded stress management detail; total lifestyle items now 7 - Section 6: Added Ketamine infusion monitoring row with continuous monitoring parameters and action thresholds; added ECG ED/ICU coverage; added renal function ICU coverage - Section 6: Changed bone density action from "Consider" to "Initiate" (directive language fix) - Section 7: Added "multi-day high-dose ketamine protocol" to ICU admission criteria

v1.0 (February 8, 2026) - Initial template creation - Budapest diagnostic criteria integrated - Comprehensive pharmacotherapy including bisphosphonates, neuropathic agents, and IV ketamine - Interventional therapies: sympathetic blocks, SCS, DRG stimulation, intrathecal baclofen - Rehabilitation section: GMI, mirror therapy, desensitization, stress loading, aquatic therapy - 12 PubMed-linked references included