How do you diagnose CRPS

Sudeck's disease: diagnosis possible without apparatus

Unclear and inadequate pain after an operation or trauma should always make you think of Sudeck's disease (CRPS). Key messages of the new line from 2018.

Paul Sudeck was the first to describe the “derailed healing inflammation”, which is now internationally known as the “complex regional pain syndrome” (CRPS). CRPS develops after injuries to extremities in 2–5% of patients, most frequently with distal radius fractures (“loco typico”). A spontaneously occurring CRPS is very rare, but minor trauma can also trigger this syndrome.

CRPS is divided into CRPS I (without a major nerve lesion) and CRPS II (with a nerve lesion). A division into a “primarily warm” and a “primarily cold” CRPS is now preferred. These categories are interesting because they entail different therapeutic options and have different prognoses.

Symptoms show up early

A primarily warm CRPS shows the typical signs of inflammation (dolor, tumor, rubor, calor), a primarily cold one includes a pale skin color and a colder temperature. CRPS II and primary cold CRPS often have a poorer prognosis (1). The modified Budapest criteria (see box) are decisive for diagnosis. In any case, sensory disorders that do not adhere to the nerve supply areas (“glove-shaped”), motor and vegetative disorders as well as body diagram disorders are groundbreaking.

Inadequate pain often occurs early after trauma or surgery during exercise and at rest. Especially distal to the fracture, the joints show pressure hyperalgesia, the skin mechanical and thermal hyperalgesia. Often there is a pronounced allodynia early in the course of the disease, which also does not correspond to the typical nerve supply areas.

In addition to a restriction in active and passive mobility, a variety of neurological symptoms sometimes dominate - such as disorders of diadochokinesis, pain-related decrease in strength, tremors, myoclonus and dystonia.

Vegetative signs are changes in skin temperature and color, edema, changes in hair and nail growth, and hyper- or hypohidrosis. These symptoms change strongly in the course of the individual. If left untreated, trophic changes quickly lead to restricted mobility and contractures.

Psychological evaluation for post-traumatic stress disorder (PTSD) and generalized anxiety disorder (GAD) should always be performed. The latter have a negative predictive value for the course (2).

Early multimodal therapy

The success of the treatment of CRPS depends on the fact that a multidisciplinary (multimodal) therapy for pain, loss of function and possible accompanying psychological disorders is provided as early as possible.

At the center of analgesic therapy are drugs that have a positive effect on the underlying neuropathy (see table). Despite little evidence, the calcium modulators gabapentin and pregabalin are administered. Ketamine infusions over several days reduce pain and improve function over a period of several weeks.

Low-dose intravenous immunoglobulins (0.5 g / kg) are ineffective in chronic CRPS and are therefore not recommended. Baclofen can be used intrathecally for dystonia in specialized centers.

In warm CRPS in the acute phase, due to the anti-inflammatory and anti-edematous effects, corticosteroids are used in a dose of 1 mg / kg body weight prednisolone equivalent. Calcitonin is characterized as ineffective. Another pillar of drug therapy are bisphosphonates, which are recommended in the guideline in a comparatively high dose. However, we usually give a lower dose due to potential side effects.

A new addition to the recommendations is N-acetylcysteine ​​(NAC), which in a comparative study was just as effective as dimethyl sulfoxide ointment (DMSO) and is virtually free of side effects.

Dimethyl sulfoxide ointment (DMSO), which is standard anti-inflammatory therapy for CRPS in the Netherlands, can be applied topically. However, the data situation is thin.

An Ambroxol ointment mixture (Ambroxol 10 g, DMSO 5 g, Linola 50 g) is not mentioned in the guideline, but is effective against allodynia (3). Ambroxol appears to reduce oxidative stress and is a sodium channel modulator.

There are some studies on naltrexone (4), but they are also not mentioned in the guideline.

Spinal cord stimulation (SCS) is only recommended for therapy-refractory patients if the trial stimulation was effective. However, there is a lack of long-term data here. The electrical stimulation of the spinal ganglia ("dorsal root ganglion stimulation", DRG) could be an alternative in the future.

Functionally, a graded exercise plan ("graded exposure") is recommended, which works in a similar way to the "fear hierarchy" for the therapy of phobias, as well as the mirror therapy according to Ramachandran. Both procedures are more effective than standard physiotherapy.

There is still no evidence of effectiveness for regional anesthetic procedures on the sympathetic nervous system (GLOA, stellate blockade). The often used "pain exposure physical therapy" (PEPT) was able to improve the function but not the pain in CRPS in studies and is therefore no longer recommended.

conclusion for practice

  • The diagnosis and therapy of CRPS have developed further in recent years.
  • Doctors and physiotherapists should be familiar with the “modified Budapest criteria”, which focus on disorders of sensitivity, motor skills and trophics that are difficult to classify.
  • The diagnosis can usually be made without additional technical examinations.
  • Multidisciplinary treatment that begins quickly is essential for a good prognosis. Here, the mirror therapy according to Ramachandran and the "graded exposure" method are important components.

Dr. med. Andreas Böger

Head physician DRK Kliniken Nordhessen, Clinic for Pain Medicine / Pain Center Kassel

Conflict of Interest: The author has received lecture fees from Mundipharma, Pfizer, and Astellas, and fees for judicial opinions.

This article is not subject to peer review.

Literature on the Internet:
www.aerzteblatt.de/lit0519
or via QR code.

Modified Budapest criteria for the CRPS

  • Persistent pain that is no longer explained by the initial trauma.
  • Patients must report at least one symptom from 3 of the 4 following categories, both in the anamnesis and at the time of the examination: - hyperalgesia (hypersensitivity to pain stimuli); Hyperesthesia (hypersensitivity to touch, allodynia);

- asymmetry of skin temperature, change in color;

- asymmetry in sweating, edema;

- reduced mobility, dystonia, tremor, "paresis" (or weakness), changes in hair or nail growth.

  • Another condition does not adequately explain the symptoms.

All points must be fulfilled!

Böger A: Sudeck's disease - pain control and restitution of functionality. Deutsches Ärzteblatt 2018; 115 (3): 76-80 FULL TEXT
German Society for Neurology: Diagnosis and therapy of complex regional pain syndromes (CRPS). https://www.dgn.org/leitlinien/3618-ll-030-116-diagnostik-und-therapie-komplexer-regionaler-schmerzsyn drome-crps-2018 (last accessed on 2 January 2019).
Kern U, et al .: Topical Ambroxol for the Therapy of CRPS - A New Option. Poster Pain Congress Mannheim 2016.
Chopra P, Cooper M: Treatment of Complex Regional Pain Syndrome (CRPS) using low dose naltrexone (LDN). J Neuroimmune Pharmacol 2013; 8 (3): 470-6 CrossRefMEDLINE PubMed Central