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Complex Regional Pain Syndrome (CRPS)

Essentials

  • CRPS is a complex pain syndrome that can be triggered by mild or moderate tissue damage (e.g. wrist fracture).
  • It is essential for the recovery process to use the limb in spite of symptoms, to provide physiotherapy and psychological methods for pain management, and to treat the pain with medication normally used for neuropathic pain.

Epidemiology

  • 3-4 times more common in women
  • 60% of cases involve upper and 40% lower limbs
  • The most common underlying factors: fractures (45%), strains (12%), elective surgery (12%), spontaneous CRPS (< 10%)
  • Three out of four patients with CRPS recover within the first year. Recovery may also take place at a later phase of the illness.

Clinical picture and diagnosis

  • The pain often starts several weeks after the injury.
  • The extremity often initially swells, becomes red and shows increased sweating (1-3 months). As months pass, the warm limb often gets colder and loses mobility. Clinical symptoms may spread proximally and sometimes to the healthy limb. Usually these symptoms are initially stronger and may alleviate and heal while the CRPS symptoms subside.
  • Sometimes the symptom picture includes trophic symptoms, such as shininess of the skin, excessive growth of hair, nail changes, dystonia or tremor.
  • There is often both increased (positive symptom) and decreased (negative symptom) sensitivity of the skin on the affected limb.
  • CRPS has a significant negative effect on the quality of life.
  • CRPS is often also associated with limb agnosia and neglect-like symptoms. CRPS may sometimes spread to the limb that was earlier healthy, as well.
  • CRPS is divided into two types: CRPS Type I (no significant nerve damage shown) and CRPS Type II (nerve damage shown).
  • Budapest criteria 2010:
    1. The patient has continuing pain which is disproportionate to the inciting event
    2. The patient has a history of at least one symptom in each of three categories (clinical diagnostic criteria) or one symptom in each of the four categories (diagnostic criteria for research):
      1. Sensory symptoms: hyperaesthesia or allodynia
      2. Vasomotor symptoms: temperature asymmetry, varying or asymmetric skin colour
      3. Sweating changes, sweating asymmetry or oedema
      4. Motor or trophic changes: decreased range of motion, weakness, tremor, dystonia or trophic changes (changes to hair, nail or skin)
    3. At the time of examination, at least one diagnostic finding in two or more categories:
      1. Sensory findings: hyperalgesia (to pinprick) or allodynia (to light touch, pressure or joint movement)
      2. Vasomotor findings: temperature asymmetry (difference between sides > 1°C), varying or asymmetric skin colour
      3. Oedema, sweating changes or sweating asymmetry
      4. Motor or trophic changes: decreased range of motion, weakness, tremor, dystonia or trophic changes (changes to hair, nail or skin)
    4. No other diagnostic explanation for the symptoms and findings

Risk factors

  • Immobilization
  • Pain exceeding 5/10 NRS (numeric rating scale) one week after fracture
  • Other musculoskeletal disease, such as rheumatoid arthritis.
  • Genetic factors; there are even families with CRPS, but the exact inheritance pattern is not yet known. Subtypes B62 and DQ8 of the HLA gene are known to be associated with CRPS symptoms with dystonia.
  • In studies, depression or anxiety have not been shown to be predisposing factors; instead, posttraumatic stress disorder may possibly predispose to CRPS. Psychological factors, such as severe anxiety, pain-related fear, catastrophizing and strong negative reactions to limb stimuli, have been associated with worse clinical course.

TreatmentIntravenous Sympathetic Blockade for Pain Relief in Reflex Sympathetic Dystrophy, Local Anesthetic Sympathetic Blockade for Complex Regional Pain Syndrome

  • Requires multidisciplinary rehabilitation carried out through cooperation between a physician, physiotherapist and psychologist.
  • If effective analgesic medication combined with physiotherapy aimed at normalization of the range of motion does not produce results within a couple of weeks, the patient should be referred to a multidisciplinary, specialized pain clinic without delay.
  • Gradually improving perception of the limb as well as exercise treatment and "toughening" of the limb are the cornerstone of the rehabilitation process requiring patience ("use it or lose it").
  • An assessment, instructions and exercises provided by a psychologist are essential. These include, for example, revoking the fear-avoidance behaviour as well as learning and implementation of various pain management methods).
  • Analgesic medication should be used as indicated in neuropathic pain: gabapentin (300-1 200 mg three times daily), pregabalin (150-300 mg twice daily) amitriptyline (25-75 mg once daily), nortriptyline (25-75 mg once daily), duloxetine (60-120 mg once daily), venlaflaxine (150-225 mg once daily) etc.
  • Potent opioids are not recommended.
  • When symptoms begin, short-term glucocorticoid treatment at moderate decreasing doses may alleviate the pain.
  • Bisphosphonates may alleviate the inflammation in patients with CRPS.
  • Sympathetic blockade Local Anesthetic Sympathetic Blockade for Complex Regional Pain Syndrome may be used to facilitate or promote physiotherapy. There is no actual proof of an alleviating effect on the pain, and repeated series of local anaesthetic sympathetic blockade are not recommended.
  • Surgical sympathectomy will not help.
  • Treatment methods in specialized care
    • Epidural stimulation therapy
    • Dorsal root ganglion stimulation (DRG) has been investigated but more research is needed.
    • Navigated repetitive transcranial magnetic stimulation (rTMS)
  • A scroring system for the spectrum of symptoms in CRPS, where the occurrence of each symptom or sign gives 1 point, may be used in the assessment of the initial situation and follow-up. A change of five points within the follow-up is regarded as good response.

CRPS Symptom Score. Each symptom/sign gives one point.

Does the patient report the following symptoms in the CRPS limb?Yes=1No=0
Pain
Allodynia or hyperalgesia
Temperature asymmetry
Skin colour asymmetry
Sweating asymmetry
Asymmetric oedema
Trophic changes (in skin, nails, hair)
Lack of (motor) strength
Sum/8 points
Signs observed on examination of the CRPS limbYes=1No=0
Hyperalgesia to sharp object
Allodynia
Temperature difference > 1°C between sides
Skin colour asymmetry
Sweating asymmetry (palpated)
Asymmetric oedema
Trophic changes (in skin, nails, hair)
Lack of (motor) strength
Sum/8 points
Total points/16 points

References

  • Harden RN, Maihofner C, Abousaad E ym. A prospective, multisite, international validation of the Complex Regional Pain Syndrome Severity Score. Pain 2017;158(8):1430-1436. [PubMed]
  • den Hollander M, Goossens M, de Jong J ym. Expose or protect? A randomized controlled trial of exposure in vivo vs pain-contingent treatment as usual in patients with complex regional pain syndrome type 1. Pain 2016;157(10):2318-29. [PubMed]
  • Cruccu G, Garcia-Larrea L, Hansson P ym. EAN guidelines on central neurostimulation therapy in chronic pain conditions. Eur J Neurol 2016;23(10):1489-99. [PubMed]
  • Shim H, Rose J, Halle S et al. Complex regional pain syndrome: a narrative review for the practising clinician. Br J Anaesth 2019;123(2):e424-e433. [PubMed]

Evidence Summaries ⬆