On September 24, 2018, Katsuhiro Toda, Department of Orthopedic Surgery, Kitohiroshima Toyohir Hospital, Japan, published a research article for risk factors of complex regional pain syndrome in the Juniper Online Journal of Orthopedic & Orthoplastic Surgery. ( Katsuhiro T. Risk Factor for Complex Regional Pain Syndrome. JOJ Orthoped Ortho Surg. 2018; 2(1): 555579. DOI: 10.19080/JOJOOS.2018.02.555579)
The goals for his research were to
1) find the cause, set of causes, or manner of causation of CRPS;
2) find related disorders or diseases so that treatments for the related disorder could be applied to CRPS;
3) help with early detection of CRPS;
4) help with determining better therapy for injuries such as fractures to avoid CRPS.
His conclusion stated that CRPS might be included in “Central Sensitivity Syndrome” (CSS), a recently coined term that consists of a variety of pain disorders across multiple medical disciplines. Disorders already included in CSS are Fibromyalgia, Temporomandibular joint disorder (TMJ), Irritable Bowel Syndrome, Interstitial cystitis, headache/migraine, chronic low back pain, and chronic neck pain.
Concerns
One issue Toda discovered while researching the risk factors for CRPS was that the ever-changing criteria for the disorder meant the same person with the same symptoms but at different times would not necessarily have the same diagnosis each time. The continuing changes in the name of the disorder may also mean that some relevant studies may not have been included in the research. The two most recent names are Chronic Regional Pain Disorder (CRPS), and Reflex Sympathetic Dystrophy (RSD).
Another issue Toda raised was the ethical topic of orthopedic surgeons choosing not to perform needed surgery based on the chance that the operation could result in CRPS.
A diagnosis of CRPS is higher for those with higher incomes and higher academic success. Although Toda lists these as risk factors for CRPS, it is more likely that those without adequate income or academic excellence are less likely to have the means to get an accurate diagnosis.
Although many medical practitioners believe that genetics is a significant factor in developing CRPS, there are no definitive studies that point to a specific gene or set of genes.
High-Risk Factor – Sex
Being female is a significant risk factor. A review of Mayo Clinic records showed that women were diagnosed with CRPS four times higher than men following orthopedic surgery. In the Netherlands’ databases, he found that women were diagnosed three times higher than men. In Denmark, the ratio again was 4:1, with women being four times more likely to develop CRPS.
In a fracture of a bone, the results were not as clearly defined. Women appeared to be slightly more likely to develop CRPS than men. But the choice of treatment for the fracture also played a significant role in who developed CRPS.
High-Risk Factor – Immediate Pain
Although one of the primary diagnostic criteria is “continuing pain, which is disproportionate to any inciting event,” there is a perception that the CRPS develops some time after the triggering event. Toda’s research indicates that “disproportionate pain” at the time of the inciting incident is a “red flag” for CRPS. He defined “disproportionate pain” as five or higher, three days after the event. The studies he used were of traumatic wrist and hand injuries. The risk factor he found was 3.61.
High-Risk Factors – Related Disease/Disorder
These are the pre-existing diseases or disorders that Toda idenitied as related to CRPS from case-controlled studies.
- History of allergies and/or skin hypersensitivity
- Asthma
- Trouble falling asleep
- History of Migraines – Also a predictor of more severe CRPS
- Osteoporosis
High-Risk Factors – Probably Related Disease/Disorder
These are the pre-existing diseases or disorders that have a strong correlation with the development of CRPS but did not have case-controlled studies.
- Rheumatoid Arthritis (Almost 3 times increase in risk)
- Osteoarthritis or Lower Back Pain (Almost 2 times increase in risk)
- Previous development of CRPS
- Fibromyalgia
- Multiple Sclerosis
- Hypertriglyceridemia
Risk Factor – Injury
The risk of developing CRPS after an injury varied by the type of injury, the location of the damage, and the treatment chosen. In all cases, the chance of developing CRPS after an injury was between 1 and 3 percent. The location of the injury is significant. Injuries to the extremities are more likely to trigger CRPS than an injury to the trunk of the body.
Risk Factor – Stress
In a limited set of data, Toda drew an intriguing conclusion – “patients who experience more life events appeared to have a greater chance of developing CRPS1.” The definition of “life-event” in this context is a stressful event such as family conflict, death of relatives, or significant job-related problems. Both a recent life-event and cumulative occurrences appeared to increase the odds of developing CRPS. A recent “life-event” was reported in 60% to 80% of cases as compared to 20% in a control group.
Medically Induced Risk Factors
- Immobilization of the affected limb increased risk of developing CRPS
- Use of ACE Inhibitors for control of high blood pressure
- Increased length time under anesthesia
CRPS – Associated Disorders
The medical term is concomitant. These are the diseases or disorders that Toda found that existed at the same time as CRPS in the patients studied. These could have been pre-existing, but not necessarily.
- Headaches/Migraines
- Lower Back Pain
- Irritable Bowel Syndrome
- Fibromyalgia
