Litigation Guides

Complex Regional Pain Syndrome

Complex Regional Pain Syndrome (CRPS) is a chronic pain disorder, triggered by trauma, characterized by disproportionate and persistent pain, swelling, and various neurological symptoms, with a history dating back to the 1500s but no definitive cure. The condition's complexity and the variability in symptoms often lead to delayed diagnosis and treatment, potentially giving rise to legal claims for affected patients.

Medically Reviewed


What is Complex Regional Pain Syndrome?

Complex Regional Pain Syndrome (CRPS) is a rare, chronic pain disorder that is caused by sustaining trauma to the extremities. The symptoms include persistent weakness, inflammation, swelling, and excess sweating. The most curious symptom is extreme pain from a source that does not typically cause pain (or pain that is disproportionate from the injury), phenomena referred to as allodynia or hyperalgesia. It is an incurable disease that leaves many questions unanswered, as it is not very well understood despite it first being observed in patients dating back to the 16th century.


Timeline of the History of Complex Regional Pain Syndrome

  • 1500s – CRPS is first noted by a surgeon after bloodletting (an ancient practice of withdrawing blood from a person’s veins for therapeutic reasons)
  • 1864 – CRPS is first mentioned in North America during the Civil War, when the aftermath of gunshot wounds caused extreme burning pain and shiny, reddened skin
  • 1872 – The term causalgia is first coined to describe a neurological disorder that produces long-lasting, intense pain after an injury to a peripheral nerve (which is used to describe CRPS type II)
  • 1994 – The International Association for the Study of Pain (IASP) developed the current name for CRPS
  • 2003 – Budapest criteria for current CRPS diagnosis
  • 2010 – CRPS Severity Score is created, which includes eight signs and eight symptoms that are looked for during history intake and a physical examination1
Woman holding painful foot

Symptoms of CRPS

The most notable symptom of CRPS is that its symptoms, in and of themselves, do not feel proportionate to the injury that triggered them. Oftentimes, no onset injury needs to occur for CRPS to develop. Symptoms can include:

  • Persistent weakness
  • Inflammation and swelling
  • Edema
  • Excessive sweating irrespective of heat or exercise (hyperhidrosis)
  • Extreme pain disproportionate to the initial injury
  • Skin color asymmetry
  • Motor changes
  • Decreased range of motion
  • Life-long pain
  • Psychological co-morbidities due to the pain’s persistence, such as isolation and depression2

Diagnosis of CRPS

CRPS usually first starts with the patient suffering an injury, although it is not a requirement that an injury precede the symptoms. According to the IASP criteria for CRPS, the disorder can be diagnosed when 2 to 4 of the following criteria are met:

  1. The presence of a preceding event or injury (not necessary, however, because 5% to 10% of patients will have no such history)
  2. Continuous pain which is disproportionate to the initial injury
  3. Swelling or blood flow changes in the skin or sweat gland abnormalities
  4. An absence of another condition that would otherwise explain the symptoms3

The Budapest criteria, created in 2003, set forth standards more specific to CRPS. According to its measures, patients must meet all four of the following criteria:4

  1. Continuous pain disproportional to the inciting event
  2. At least one symptom in three or more of the following categories –
    1. Sensory
    2. Vasomotor (temperature and skin color asymmetries)
    3. Submotor/edema (swelling and sweating changes)
    4. Motor/trophic (weakness, decreased range of motion, tremors etc)
  3. At least one sign is present upon evaluation in two or more of the above categories
  4. Absence of another diagnosis that would better explain the symptoms and signs

Causes of CRPS

There are two major subtypes of CRPS – Type I and Type II – with a third subtype for cases that do not fully fit into either of the main two types:5

  • Type I – occurs in the absence of major nerve injury
    • Accounts for the majority of CRPS cases
    • Follows a relatively minor trauma, such as a sprain, twist, dislocation, or soft tissue injury, or in some cases, no injury at all
    • Most common in populations under age 186
  • Type II – occurs in the presence of a major, identifiable nerve injury

There are two distinct phases of CRPS:

  • The “warm” phase in the initial period of the disease which consists of:
    • “Classic” inflammation - pain, redness, heat, swelling, and loss of function
    • “Neurogenic” inflammation – activated by the peripheral nervous system; increased sensitivity in pain receptors
  • The “cold phase” approximately six months after:
    • Changes in soft tissue and bones7

Other causes and exasperators include:

  • The central nervous system changing the way the brain comprehends the state of the injured extremity
  • Psychological stressors (patients with higher reported anxiety, self-reported pain scores, depression, or PTSD had worse symptoms)
    • These stressors have been attributed to an increase in the release of anxiety-related biomarkers that increase one’s perception of pain.
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CRPS Prognosis and Treatment

  • There is no current treatment to cure CRPS. Treatment goals focus on pain reduction and increasing functionality.8
  • Treatments include physical therapy, occupational therapy, cognitive behavioral therapy, neuropathic medications, and anti-inflammatories.9
  • An experimental procedure, neuromodulation, has been promising, where portions of the spinal nerves are stimulated or blocked to reduce pain.
  • Medications that slow bone loss (bisphosphonates) are also used.10
  • Prognosis is highly variable and can range from mild to chronic persistence.
  • CRPS is likely a chronic condition
  • CRPS is more prevalent in females and in patients with psychiatric comorbidities

Legal Issues

  • Due to the variability in symptoms, most patients encounter a delay in diagnosis and treatment of CRPS.11
  • Failure to timely and properly diagnose CRPS may become a viable legal claim for a patient.

Works Cited


Shim H, Rose J, Halle S, Shekane P. Complex regional pain syndrome: a narrative review for the practising clinician. BJA Br J Anaesth. 2019;123(2):e424-e433.


Shim H, Rose J, Halle S, Shekane P. Complex regional pain syndrome: a narrative review for the practising clinician. BJA Br J Anaesth. 2019;123(2):e424-e433. URL




Halicka M, Vittersø AD, Proulx MJ, Bultitude JH. Neuropsychological Changes in Complex Regional Pain Syndrome (CRPS). Behav Neurol. 2020;2020:4561831. URL


Misidou C, Papagoras C. Complex Regional Pain Syndrome: An update. Mediterr J Rheumatol. 2019;30(1):16-25. URL


Weissmann R, Uziel Y. Pediatric complex regional pain syndrome: a review. Pediatr Rheumatol Online J. 2016;14:29. URL


Misidou C, Papagoras C. Complex Regional Pain Syndrome: An update. Mediterr J Rheumatol. 2019;30(1):16-25. URL




Shim H, Rose J, Halle S, Shekane P. Complex regional pain syndrome: a narrative review for the practising clinician. BJA Br J Anaesth. 2019;123(2):e424-e433. URL


Misidou C, Papagoras C. Complex Regional Pain Syndrome: An update. Mediterr J Rheumatol. 2019;30(1):16-25. URL


Lazaro RP. Complex regional pain syndrome: medical and legal ramifications of clinical variability and experience and perspective of a practicing clinician. J Pain Res. 2016 Dec 19;10:9-14. URL

About the authors

Autumn Barnes, MD

Autumn Barnes, MD, is a seasoned medical professional with a keen focus on Women's Health, underpinned by a rich background that spans various facets of the medical field. Beginning her academic career with a Bachelor of Science in Neuroscience from UCLA, Dr. Barnes developed a profound interest in patient care, further amplified during her tenure as a Care Extender at Ronald Reagan Hospital, where she was recognized for her exceptional service. Her journey through medicine led her to St. George's University School of Medicine, culminating in a residency in Family Medicine at HCA Florida Oak Hill Hospital. Dr. Barnes's experience is complemented by her roles in medical administration and data analysis, notably improving operational efficiencies and patient care processes.

Her professional narrative is characterized by a deep commitment to healthcare, especially in managing and understanding the complexities of Women’s Health. Dr. Barnes's transition into Obstetrics and Gynecology, fueled by her clinical rotations and a foundational role at engage2Health, highlights her ability to bridge the gap between clinical practice and healthcare data management. This unique blend of skills ensures that her contributions to medical content are not only informed by firsthand clinical experience but also by a comprehensive understanding of healthcare's broader implications, making her an invaluable asset to any medical platform seeking to enhance its content with expertise and insight.

Wendy Ketner, M.D.

Wendy Ketner, M.D.

Dr. Wendy Ketner is a distinguished medical professional with a comprehensive background in surgery and medical research. Currently serving as the Senior Vice President of Medical Affairs at the Expert Institute, she plays a pivotal role in overseeing the organization's most important client relationships. Dr. Ketner's extensive surgical training was completed at Mount Sinai Beth Israel, where she gained hands-on experience in various general surgery procedures, including hernia repairs, cholecystectomies, appendectomies, mastectomies for breast cancer, breast reconstruction, surgical oncology, vascular surgery, and colorectal surgery. She also provided care in the surgical intensive care unit.

Her research interests have focused on post-mastectomy reconstruction and the surgical treatment of gastric cancer, including co-authoring a textbook chapter on the subject. Additionally, she has contributed to research on the percutaneous delivery of stem cells following myocardial infarction.

Dr. Ketner's educational background includes a Bachelor's degree from Yale University in Latin American Studies and a Doctor of Medicine (M.D.) from SUNY Downstate College of Medicine. Moreover, she is a member of the Board of Advisors for Opollo Technologies, a fintech healthcare AI company, contributing her medical expertise to enhance healthcare technology solutions. Her role at Expert Institute involves leveraging her medical knowledge to provide insights into legal cases, underscoring her unique blend of medical and legal acumen.

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