The definition of the IASP (International Association for the Study of Pain) describes Complex Regional Pain Syndrome (CRPS) as being a set of locally occurring painful conditions following trauma, which are mainly expressed distally and exceed in severity and duration the expected clinical course of the original trauma, often resulting in a substantial reduction in motor skills, characterised by variable progression over time.
A distinction is made between CRPS type I without nerve injury and CRPS type with proven nerve injury. More recently still, a third type has been added, known as CRPS-NOS (Not Otherwise Specified). This relates to conditions that only partially meet the diagnostic criteria of CRPS, but where no other diagnosis can be made.
CRPS is a pain syndrome that can occur after surgery or trauma. However, CRPS without a causal reason is also possible.
The incidence of CRPS is 26.2 per 100,000 person/years and is more frequently seen in the upper extremities. A fracture is the most frequent initiating event. Females have CRPS three times more often than males. The highest incidence has been established in females between the ages of 61 and 70 years. CPRS usually affects one extremity, but cases of multiple extremities have been described.
There is no uniformity in the pathophysiology of CRPS. Not only afferent mechanisms such as inflammation, and efferent mechanisms such as dysregulation of the involuntary nervous system, but also central mechanisms such as psychological factors, have all been described.
Signs and symptoms
CRPS usually has a glove-like appearance in the arm or a sock-like appearance in the leg. The affected area is often more extensive than the area of the initial injury.
CRPS is characterised by a combination of pain, and sensory, vasomotor, sudomotor, motor and trophic phenomena. The pain is continuously present. Allodynia of the skin (pain by touching), left/right difference of skin temperature and/or skin colour changes, are typical of CRPS. Anamnestic, CRPS patients can have oedema and/or increased transpiration in the affected extremity. The patient can complain about functional restrictions, such as paresis, tremor or dystonia, and changes in hair and/or nail growth. Symptoms often become worse during and after physical effort. CRPS symptoms are not constant over time.
On physical examination, vasomotor, sudomotor and trophic phenomena may be observed. There are skin colour differences, oedema, and altered hair and nail growth in the affected and contralateral extremity. Sensory vasomotor symptoms are present on palpation.
Allodynia, hyperalgesia and skin temperature differences between the affected and contralateral extremity are noted. On functional examination, motor disturbances are seen due to weakness, stiffness, pain due to involuntary movements, tremor and dystonia.
Additional neurological examination does not reveal other deficits (e.g., reflex differences), except for those abnormalities mentioned earlier.
Additional Somatic Diagnostics
There are no specific clinical tests and/or additional examinations characteristic for the diagnosis CRPS.
Additional Psycho-cognitive Diagnostics
- RAND-36 (quality of life)
- VAS Pain (maximal, minimal, actual, average/week)
- PCS (catastrophising)
- HADS (fear and depression)
Whether or not somatic treatment is indicated is based on the pain diagnosis. Based on the findings of the pain questionnaires, additional diagnostics and/or multidisciplinary treatment consisting of various non-somatic treatments may be necessary.
- Psychological Treatment
- Depression Treatment
- Cognitive-Behavioural Treatment
- Rehabilitation Treatment
Depending on the mechanism that plays a role in a particular CRPS patient, various treatment strategies can be applied. The efficacy of these evidence-based treatments has been catalogued in the Dutch National Guidelines Complex Regional Pain Syndrome Type I.
- O2 radical scavengers such as dimethyl sulfoxide and N-acetylcysteine, and biphosphonates such as clodronate, aledronate and corticosteroids, are effective.
- Ketamine IV, gabapentine.
- Calcium influx blockers, ketanserine
- Spasmolytic treatment
- Oral spasmolytic therapy with benzodiazepines or baclofen oral, baclofen intrathecal in patients with dyskinesia.
Interventional Pain Treatment
- Stellate ganglion test block (arm)
- Stellate ganglion RF treatment (arm)
- Lumbar sympathetic test block (leg)
- Lumbar sympathetic RF treatment (leg)