Complex Regional Pain Syndrome (CRPS)
Learn more about common pain conditions, their development, and the pain mechanism.
Overview
CRPS (Complex Regional Pain Syndrome) has many different manifestations and names, including Sudeck’s atrophy, reflex sympathetic dystrophy, algodystrophy, and sympathetic reflex dystrophy. However, the internationally standardized term Complex Regional Pain Syndrome (CRPS) should be used. Despite many names and its first description over 150 years ago, CRPS remains poorly understood. People affected by CRPS suffer from constant, often severe pain.
Causes
CRPS is usually triggered by a traumatic injury, with or without nerve damage. The symptoms typically appear within weeks of an injury. Injuries associated with CRPS can include bone fractures, cuts, surgical procedures, burns, or even a simple sprain. Typically, the pain is unusually severe and lasts longer than expected. Usually, only one extremity (e.g., a hand or arm) is affected, although it can very rarely spread to other body regions. The exact mechanisms behind CRPS are unknown, and the complex nature of its symptoms suggests it does not have a single cause.
Symptoms
The main symptom of CRPS is pain, often described as a combination of burning, stabbing, and tingling sensations. The skin of the affected limb can be extremely sensitive. Light touches, which are normally not painful, or changes in the surrounding temperature, can trigger intense pain. Neuropathic positive symptoms such as hyperalgesia and allodynia are common. Sudden swelling, skin color changes, and temperature variations can also occur. The limb may experience functional impairments, such as joint stiffness and movement restrictions. The skin can appear warm, red, and dry initially but may become cold, bluish, and sweaty later. Noticeable changes in hair and nail growth are also typical. Additionally, patients may experience “strange sensations,” such as a sense of physical detachment from the limb. Compared to the healthy limb, the affected limb may feel smaller or larger.
Diagnosis
Diagnosing CRPS is challenging as there is no definitive test or imaging technique. CRPS is usually diagnosed by excluding other conditions that may present with similar symptoms. Clinically, the Budapest criteria established by the International Association for the Study of Pain (IASP) in 2003 are used.
Treatment
It is crucial to start treating CRPS as soon as possible and aggressively to prevent chronicity and support healing. CRPS treatment always involves a combination of therapeutic measures. The goal is not only pain reduction but also functional improvement or preservation of the affected limb.
The treatment plan must be tailored to the individual patient, typically combining non-pharmacological, pharmacological, and sometimes interventional approaches. Treatment options include:
Self-management
Psychological Support/Therapy
Ergo- and Physiotherapy
Pharmacological Therapy
– NSAIDs (e.g., Ibuprofen, Paracetamol, Metamizol)
– Antineuropathic Medications
– Tricyclic Antidepressants
– SSNRI Antidepressants
– Antiepileptics
– Opioids (only for severe uncontrolled pain and under strict medical supervision)
– Local/Topical Medications
– Local Anesthetics (e.g., Lidocaine Gel)
– Amitriptyline-Ketamine Cream
– DMSO Cream
– Serial Infusion Treatments with Ketamine (NMDA Receptor Antagonist)
Interventional Treatments
– Repeated Sympathetic Nerve Blocks (Hand: Stellate Ganglion, Foot: Sympathetic Chain)
– Spinal Neuromodulation (Spinal Cord Stimulation, SCS)
Prognosis
Although CRPS can be significantly debilitating and life-limiting, the symptoms and pain in about 85% of patients with CRPS substantially improve within two years.
