Complex Regional Pain Syndrome (CRPS)

A chronic pain condition characterized by severe burning pain and autonomic dysfunction

Table of Contents

Quick Facts

  • Type: Chronic Pain Disorder
  • ICD-10: G90.5
  • Prevalence: 5-26 per 100,000
  • Onset: Usually after injury

Overview

Complex Regional Pain Syndrome (CRPS) is a chronic pain condition that typically affects one arm or leg, usually developing after an injury, surgery, stroke, or heart attack. The pain is disproportionately severe compared to the original injury and is often described as a constant burning or throbbing sensation.

Previously known as Reflex Sympathetic Dystrophy (RSD) and Causalgia, CRPS is now classified into two types: CRPS-1 (formerly RSD) occurs without a confirmed nerve injury, while CRPS-2 (formerly Causalgia) occurs with evidence of nerve damage. Both types share similar symptoms and treatment approaches.

The condition affects the sympathetic nervous system, which controls blood flow, skin temperature, and sweat production. This dysfunction leads to the characteristic combination of severe pain, swelling, skin changes, and temperature abnormalities. CRPS is believed to result from dysfunction in the central or peripheral nervous systems, though the exact mechanisms remain incompletely understood.

Early recognition and treatment are crucial for CRPS, as the condition can progress through different stages and may become irreversible if left untreated. With appropriate intervention, particularly when started early, many patients can achieve significant improvement in pain and function, though some may experience persistent symptoms requiring long-term management.

Symptoms

CRPS symptoms typically begin after an injury or trauma and are often described as being out of proportion to the original injury. The condition progresses through different stages with varying symptom patterns.

Primary Symptoms

Severe Burning Pain

Constant, intense burning or stabbing pain

 Difficulty with Movement

Swallowing difficulties and movement problems

 General Malaise

Overall feeling of being unwell

 Muscle Weakness

Progressive weakness in the affected limb

Physical Changes

  • Skin color changes: Red, blue, pale, or mottled appearance
  • Temperature changes: Affected limb feels warmer or cooler than normal
  • Swelling: Edema in the affected area
  • Skin texture changes: Shiny, thin, or thickened skin
  • Excessive sweating: Increased perspiration in affected area
  • Hair and nail changes: Faster or slower growth, changes in texture

Sensory Symptoms

  • Allodynia: Pain from normally non-painful stimuli (light touch)
  • Hyperalgesia: Increased sensitivity to painful stimuli
  • Hyperpathia: Delayed, prolonged pain response
  • Decreased sensation or numbness
  • Changes in heart rate and blood pressure

Motor and Functional Symptoms

  • Decreased range of motion
  • Muscle spasms and tremors
  • Coordination problems
  • Muscle atrophy (wasting)
  • Dystonia (abnormal muscle contractions)
  • Functional impairment of the affected limb

Psychological Symptoms

  • Depression and anxiety
  • Sleep disturbances
  • Irritability and mood changes
  • Fear of movement (kinesiophobia)
  • Cognitive changes

Stages of CRPS

Stage 1 (Acute, 1-3 months)

  • Severe burning or aching pain
  • Increased skin sensitivity
  • Localized swelling
  • Muscle spasms
  • Restricted movement
  • Rapid nail and hair growth

Stage 2 (Dystrophic, 3-6 months)

  • More constant pain
  • Swelling spreads
  • Decreased hair growth
  • Nails become cracked or brittle
  • Muscle atrophy begins
  • Joint stiffness

Stage 3 (Atrophic, after 6 months)

  • Irreversible changes to skin and bones
  • Marked muscle atrophy
  • Severely limited mobility
  • Contractures may develop
  • Bone demineralization

Causes

CRPS typically develops after an injury or trauma, though the exact mechanisms are not fully understood. The condition appears to result from abnormal responses in the nervous and immune systems.

Triggering Events

  • Fractures: Especially wrist, ankle, or foot fractures
  • Sprains and strains: Soft tissue injuries
  • Surgical procedures: Any surgery on the extremities
  • Nerve injuries: Direct damage to peripheral nerves
  • Heart attack: Can trigger CRPS in the arm
  • Stroke: May lead to CRPS development
  • Infections: Rarely, infections can trigger CRPS
  • Immobilization: Prolonged casting or splinting

Proposed Mechanisms

  • Peripheral sensitization: Increased sensitivity of pain receptors
  • Central sensitization: Enhanced pain processing in the spinal cord and brain
  • Sympathetic nervous system dysfunction: Abnormal autonomic responses
  • Neurogenic inflammation: Inflammatory responses mediated by nerves
  • Cortical reorganization: Changes in brain mapping of the affected limb
  • Autoimmune factors: Immune system attacking healthy tissues

Risk Factors for Development

  • Genetic predisposition: Family history of CRPS or related conditions
  • Gender: More common in women (3-4:1 ratio)
  • Age: Peak incidence around 40-60 years
  • Psychological factors: History of anxiety or depression
  • Smoking: May increase risk
  • Vitamin C deficiency: Low levels may predispose to CRPS

Types of CRPS

  • CRPS-1 (Type I): No definable nerve lesion (90% of cases)
  • CRPS-2 (Type II): Associated with a defined nerve injury (10% of cases)

Risk Factors

Several factors may increase the likelihood of developing CRPS after an injury or trauma:

Demographic Risk Factors

  • Gender: Women are 3-4 times more likely to develop CRPS
  • Age: Most common between ages 40-60, but can occur at any age
  • Genetics: Family history of CRPS or autoimmune conditions
  • Race: More common in Caucasians

Medical Risk Factors

  • Previous CRPS: History of CRPS increases risk of recurrence
  • Autoimmune disorders: Conditions affecting the immune system
  • Migraine headaches: Associated with increased CRPS risk
  • Asthma: May be a predisposing factor
  • Osteoporosis: Bone density problems
  • Anxiety or depression: Pre-existing psychological conditions

Injury-Related Risk Factors

  • Fractures: Especially distal radius (wrist) fractures
  • Severe trauma: High-energy injuries
  • Crush injuries: Significant tissue damage
  • Multiple surgeries: Repeated procedures on the same limb
  • Prolonged immobilization: Extended periods in casts or splints

Lifestyle Risk Factors

  • Smoking: May impair healing and increase inflammation
  • Poor nutrition: Vitamin C deficiency specifically
  • Sedentary lifestyle: Poor physical conditioning
  • High stress levels: Chronic psychological stress

Treatment-Related Risk Factors

  • Inadequate pain control after injury
  • Delayed mobilization after injury
  • Aggressive physical therapy too early
  • Use of tourniquets during surgery
  • Tight casts or bandages

Diagnosis

Diagnosing CRPS can be challenging as there is no single definitive test. Diagnosis is based on clinical criteria, patient history, and exclusion of other conditions.

Clinical Criteria (Budapest Criteria)

For CRPS diagnosis, the patient must report symptoms in at least three of the following categories:

Sensory Symptoms

  • Hyperesthesia (increased sensitivity to stimuli)
  • Allodynia (pain from normally non-painful stimuli)

Vasomotor Symptoms

  • Temperature asymmetry
  • Skin color changes
  • Skin color asymmetry

Sudomotor/Edema Symptoms

  • Edema
  • Sweating changes
  • Sweating asymmetry

Motor/Trophic Symptoms

  • Decreased range of motion
  • Motor dysfunction (weakness, tremor, dystonia)
  • Trophic changes (hair, nails, skin)

Physical Examination

  • Visual inspection: Color, swelling, skin changes
  • Temperature assessment: Comparing both limbs
  • Sensory testing: Light touch, pin prick, vibration
  • Motor assessment: Strength, range of motion, coordination
  • Autonomic function: Sweating patterns, hair growth

Diagnostic Tests

  • Bone scan (three-phase): Shows increased blood flow and bone turnover
  • X-rays: May show osteoporosis in later stages
  • MRI: Can detect bone marrow edema and soft tissue changes
  • Quantitative sensory testing: Measures pain thresholds
  • Thermography: Documents temperature differences
  • Sudomotor testing: Assesses sweating function

Differential Diagnosis

Other conditions that may mimic CRPS include:

  • Infection (cellulitis, osteomyelitis)
  • Vascular disorders
  • Nerve entrapment syndromes
  • Autoimmune conditions
  • Phantom limb pain
  • Conversion disorder
  • Fibromyalgia
  • Myofascial pain syndrome

Specialized Testing

  • Sympathetic nerve blocks: Diagnostic and therapeutic
  • Stellate ganglion block: For upper extremity CRPS
  • Lumbar sympathetic block: For lower extremity CRPS
  • Psychological evaluation: Assessment of psychological factors

Treatment Options

CRPS treatment is most effective when started early and typically involves a multidisciplinary approach combining medications, physical therapy, psychological support, and interventional procedures.

Medications

First-Line Medications

  • Corticosteroids: Prednisolone for acute CRPS (early stages)
  • Anticonvulsants: Gabapentin, pregabalin for neuropathic pain
  • Tricyclic antidepressants: Amitriptyline, nortriptyline
  • Topical agents: Capsaicin, lidocaine patches

Second-Line Medications

  • Opioids: For severe pain (limited duration)
  • NMDA antagonists: Ketamine (IV or topical)
  • Bisphosphonates: For bone changes and pain
  • Calcitonin: May help with bone pain
  • Free radical scavengers: Vitamin C, DMSO

Physical and Occupational Therapy

  • Gentle range of motion: Maintain joint mobility
  • Desensitization: Gradual exposure to stimuli
  • Mirror therapy: Visual feedback to retrain the brain
  • Graded motor imagery: Brain retraining techniques
  • Stress loading: Weight-bearing exercises
  • Contrast baths: Alternating hot and cold water
  • TENS units: Transcutaneous electrical nerve stimulation

Interventional Procedures

  • Sympathetic nerve blocks: Stellate ganglion or lumbar sympathetic blocks
  • Spinal cord stimulation: Implanted device to modulate pain signals
  • Intrathecal pumps: Direct spinal medication delivery
  • Dorsal root ganglion stimulation: Targeted nerve stimulation
  • Peripheral nerve stimulation: Stimulation of specific nerves

Psychological Support

  • Cognitive behavioral therapy: Pain coping strategies
  • Biofeedback: Learning to control physiological responses
  • Relaxation techniques: Stress reduction methods
  • Support groups: Peer support and education
  • Family counseling: Support for family members

Advanced Treatments

  • Sympathectomy: Surgical nerve cutting (rarely used)
  • Amputation: Last resort in severe, intractable cases
  • Ketamine infusions: High-dose IV ketamine protocols
  • Immunoglobulin therapy: IV immunoglobulin
  • Experimental treatments: Clinical trials for new therapies

Complementary Therapies

  • Acupuncture
  • Massage therapy
  • Meditation and mindfulness
  • Yoga and tai chi
  • Nutritional support
  • Herbal supplements

Prevention

While CRPS cannot always be prevented, certain strategies may reduce the risk of development after injury or surgery:

Early Mobilization

  • Avoid prolonged immobilization: Minimize casting and splinting duration
  • Early movement: Begin gentle motion as soon as medically safe
  • Proper splinting: Avoid overly tight or restrictive devices
  • Regular monitoring: Check for early signs of CRPS

Adequate Pain Control

  • Aggressive pain management: Prevent central sensitization
  • Regional anesthesia: Use of nerve blocks during surgery
  • Multimodal analgesia: Combination of different pain medications
  • Patient education: Proper use of pain medications

Vitamin C Supplementation

  • Prophylactic vitamin C: 500mg daily for wrist fractures
  • Antioxidant effects: May reduce inflammatory response
  • Duration: Continue for 50 days post-injury
  • Evidence-based: Supported by clinical studies

Risk Factor Modification

  • Smoking cessation: Improve healing and reduce inflammation
  • Stress management: Address psychological risk factors
  • Nutrition optimization: Ensure adequate vitamin and mineral intake
  • Exercise conditioning: Maintain good physical fitness

Surgical Considerations

  • Gentle tissue handling during surgery
  • Minimal tourniquet time
  • Appropriate postoperative pain control
  • Early mobilization protocols
  • Patient education about warning signs

High-Risk Patients

For patients with risk factors, consider:

  • More intensive monitoring
  • Prophylactic medications
  • Early intervention at first signs
  • Psychological support
  • Multidisciplinary team approach

When to See a Doctor

Early recognition and treatment of CRPS are crucial for optimal outcomes. Seek medical attention if you experience concerning symptoms after an injury.

Seek Immediate Medical Attention

  • Severe, disproportionate pain after an injury
  • Burning pain that doesn't improve with typical pain medications
  • Skin color changes (red, blue, pale, or mottled)
  • Temperature changes in the affected limb
  • Excessive swelling that doesn't respond to elevation
  • Extreme sensitivity to light touch
  • Inability to move or use the affected limb

Warning Signs After Injury

  • Pain that seems worse than expected for the injury
  • Pain that spreads beyond the injury site
  • Skin that feels different (texture, temperature)
  • Changes in hair or nail growth
  • Stiffness or decreased range of motion
  • Weakness or tremors in the affected limb

Follow-up Care

Continue to monitor and seek care if:

  • Symptoms worsen despite treatment
  • New symptoms develop
  • You're not responding to current treatments
  • You experience side effects from medications
  • You need psychological support
  • You have questions about your condition or treatment

Emergency Situations

  • Signs of infection (fever, red streaking, warmth)
  • Complete loss of function in the affected limb
  • Severe psychological distress or suicidal thoughts
  • Allergic reactions to medications
  • Complications from nerve blocks or procedures

Specialist Referrals

Your doctor may refer you to:

  • Pain management specialist: For specialized pain treatments
  • Neurologist: For nerve-related issues
  • Rheumatologist: If autoimmune factors suspected
  • Physical therapist: For rehabilitation
  • Psychologist: For psychological support
  • Orthopedic surgeon: For surgical considerations

Related Conditions

CRPS is associated with several related conditions and may occur alongside other chronic pain disorders:

Chronic Pain Syndrome

Persistent pain conditions affecting daily life

 Fibromyalgia

Widespread musculoskeletal pain disorder

 Peripheral Neuropathy

Nerve damage causing pain and numbness

 Depression

Mood disorder commonly associated with chronic pain

Associated Conditions

Complications of CRPS

  • Muscle atrophy and weakness
  • Joint contractures and stiffness
  • Bone demineralization
  • Chronic disability
  • Depression and anxiety
  • Social isolation
  • Medication dependence

Triggering Conditions

Medical Disclaimer: This information is for educational purposes only and should not replace professional medical advice. CRPS is a complex condition requiring specialized medical care. Early diagnosis and treatment are crucial for optimal outcomes. Always consult with qualified healthcare providers, particularly pain management specialists, for proper diagnosis and treatment. If you suspect you may have CRPS, seek medical attention promptly.

References

  1. Harden RN, Bruehl S, Stanton-Hicks M, Wilson PR. Proposed new diagnostic criteria for complex regional pain syndrome. Pain Med. 2007;8(4):326-31.
  2. Goebel A, Barker CH, Turner-Stokes L, et al. Complex regional pain syndrome in adults: UK guidelines for diagnosis, referral and management in primary and secondary care. Royal College of Physicians. 2018.
  3. 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;2(2):CD010853.
  4. Zollinger PE, Tuinebreijer WE, Kreis RW, Breederveld RS. Effect of vitamin C on frequency of reflex sympathetic dystrophy in wrist fractures: a randomised trial. Lancet. 1999;354(9195):2025-8.
  5. Bean DJ, Johnson MH, Kydd RR. The outcome of complex regional pain syndrome type 1: a systematic review. J Pain. 2014;15(7):677-90.