In Reply

Letters to the Editor Modern Principles of Diagnosis and Treatment in Complex Regional Pain Syndrome by Alexandra Melf-Marzi, Dr. med. Bettina Böhringer, Dr. med. Matthias Wiehle, and Prof. Dr. med. Constanze Hausteiner-Wiehle in issue 51–52/2022

We thank our colleagues for their valuable additions and the lively and enriching discussion.

Indeed, complex regional pain syndrome (CRPS) is a difficult pathology with an extremely variable phenomenology (including equivocal/unclear “stages”) and a challenging (differential) diagnosis (including the necessity of checking the diagnostic criteria in all locations separately in rare cases of multiple manifestations). It is not a diagnostic “dustbin,” and treatment must not be escalated because of therapeutic cluelessness. Monocausal-unidirectional concepts—historically oscillating between the extremes of exclusively somatogenic or psychogenic origin or even simulation assumptions—fail the complexity of CRPS.

In view of these challenges—and the broad readership of the Deutsches Ärzteblatt—our review concentrated on current trends in clinical-practical care (1): active approaches tackle neuroplasticity and function in an integrative way. Patients become active treatment partners. The importance of medication and interventional therapeutic measures declines: in children, pharmacological treatment is refrained from completely in many cases (lately, for example, Höfel et al., 2022 at the German Pain Congress). Geber and colleagues specify when and how bisphosphonates or glucocorticoids are indicated. Bahm emphasizes important practical surgical aspects: the problem of worsening CRPS after surgical procedures on the one hand; and complete recovery after the repair of findings that are requiring surgery on the other hand (according to the 4^th Budapest criterion, in fact most of these cases did not fulfil CRPS criteria retrospectively, and further CRPS therapeutic regimens would not have brought any).

Unfortunately we did not have the space for including more basic research. Geber as well as Gierthmühlen and colleagues mention (auto)immunological-inflammatory mechanisms with cytokine imbalances or reorganization processes in the entire nervous system. It is possible that in the future, specific cytokine/inflammatory or imaging patterns will be identified for validating the diagnosis, which will provide additional therapeutic options (for CRPS but also for other pain disorders and symptom processing in general). Potentially in the future, clearly defined specific disturbances of attention, body experience, etc will improve diagnostic accuracy (Höfel et al [2] recently stated that the complete picture of CRPS includes neurocognitive symptoms). And it is possible that—as so often in science—“special cases” contribute to the clarification of CRPS pathophysiology: by considering aspects such as central autonomic arousal or pain expectation it is to be hoped that we will develop a better understanding of how CRPS develops even without tissue injury, after myocardial infarction, stroke, or situations of extreme stress. Especially in children, medical history often does not include any injuries (2), and psychosocial stress leads to pro-inflammatory cytokine changes (3). Bahms’s observation (which we share) that CRPS very rarely occurs after burn injuries should definitely be studied.

CRPS needs the biopsychosocial interdisciplinary perspective that the ICD-11 now assumes. Dynamic interactions exist between body, psyche, and context, which can often not be separated out. Structural and functional, biochemical and neuropsychobehavioral, objective and subjective aspects are important, should not be placed in any hierarchy or stigmatized. What counts in the end is how CRPS risk groups and patients can be identified in a practical and reliable way, and whence effective preventive and therapeutic strategies can be developed.

DOI: 10.3238/arztebl.m2023.0064

Prof. Dr. med. Constanze Hausteiner-Wiehle,
Klinik und Poliklinik für Psychosomatische Medizin und Psychotherapie;
Klinikum rechts der Isar der Technischen Universität München

Abteilung für Neurologie, Klinische Neurophysiologie und Stroke Unit;

BG Unfallklinik Murnau

Dr. med. Bettina Böhringer,
BG Unfallklinik Murnau

Dr. med. Matthias Wiehle

Abteilung für Neurologie, Klinische Neurophysiologie und Stroke Unit;

BG Unfallklinik Murnau

Alexandra Melf-Marzi,
Abteilung für BG-Rehabilitation; CRPS-Ambulanz;
BG Unfallklinik Murnau, Abteilung für Anästhesie,
Intensiv- und Schmerzmedizin;
Multimodale Schmerztherapie

Conflict of interest statement

Dr. Böhringer received fees from Grünenthal for a presentation.

Prof. Hausteiner-Wiehle received lecture fees and reimbursement of travel expenses from Windach Hospital and the Lindau Psychotherapy Weeks.

The remaining authors declare that no conflict of interest exists.

References

1. Melf-Marzi A, Böhringer B, Wiehle M, Hausteiner-Wiehle C: Modern principles of diagnosis and treatment in complex regional pain syndrome. Dtsch Arztebl Int 2022; 119: 879–86

2. Höfel L, Magerl W, Maihöfner C: Das komplexe regionale Schmerzsyndrom (CRPS) – Altersabhängigkeit, Subtypspezifität und Konsequenzen für die Praxis. Schmerz 2022; 36 (Suppl 1): S17–8.

3. Harden RN, McCabe CS, Goebel A, et al.: Complex regional pain syndrome: practical diagnostic and treatment guidelines, 5th edition. Pain Med 2022; 23: 1–53