Adolescents with hEDS are more sensitive to pain, study says
Hypersensitive nervous system may be contributing to widespread pain
Adolescents with hypermobile Ehlers-Danlos syndrome (hEDS) or hypermobility spectrum disorder (HSD) are more sensitive to pain in different areas of their body, a recent study shows.
Exercise was found to help reduce pain sensitivity in both groups for the muscles involved, though not equally in the muscles tested.
The findings suggest central sensitization, when the nervous system is hypersensitive to stimuli from things that are not typically painful, may contribute to the different ways these patients experience pain. Cognitive and emotional factors may also play a part.
“Clinicians should therefore consider the role of central pain mechanisms beyond the muscles and joints,” researchers wrote.
The study, “Exploring signs of central sensitization in adolescents with hypermobility Spectrum disorder or hypermobile Ehlers-Danlos syndrome,” was published in the European Journal of Pain.
EDS is a group of genetic diseases that affect connective tissues, which give structure to joints, skin, blood vessels, and other organs. Hypermobile joints and stretchy skin are among the most common symptoms.
Patients with hEDS, HSD share similar symptoms, widespread, chronic pain
While HSD does not fulfil the diagnostic criteria for hEDS, which is the most common type of EDS, both disorders share similar symptoms. Patients with either disease can develop widespread and chronic pain.
Central sensitization leads to higher and widespread pain sensitivity in response to stimuli such as touch, light, and sound. It has been proposed as a possible mechanism underlying fatigue, mood disorders, and sleep issues in people with hEDS or HSD.
In the general population, exercise can increase pain tolerance, particularly high-intensity exercise, but this may not occur in people with chronic pain, who may instead experience greater sensitivity to pain. Whether this is the case in people with hEDS or HSD remains to be determined.
A team led by researchers in Sweden explored signs associated with central sensitization in adolescents with hEDS or HSD, as well as their levels of fatigue.
The study was conducted from November 2022 to August 2023. It analyzed 37 adolescents with hEDS or HSD in Sweden and 47 healthy volunteers ages 13 to 17. The adolescents with hEDS or HSD were older than the control group (median age 16.4 vs 15.3 years).
The participants mapped the site of their pain on a human body drawing that was divided into various sections. Most of the control group had no pain (75%) or only local pain (25%), while most adolescents with hEDS or HSD (82%) indicated pain: 22% in several body regions and 60% widespread pain. Pain intensity over the previous week was significantly higher in the hEDS/HSD group.
Pressure was applied to four muscle groups in the upper and lower back, leg, and shoulder until it became painful. Results showed the adolescents with hEDS or HSD reported a lower tolerance to pain in all muscles tested than the healthy group.
Pain after exercise was assessed by using a bicycle ergometer. Participants cycled at a steady pace, with resistance (effort) increasing every minute, until they reached a strenuous level of exertion.
Pain sensitivity eased after exercise
In both groups, pain sensitivity eased after exercise. Specifically, patients had a higher pain threshold in the leg muscle (tibialis anterior), while the control group showed a higher tolerance to pain in both leg and upper back muscles (trapezius).
After exercise, pain sensitivity in the leg was higher in patients than in the controls. A smaller but still statistically significant difference was found in the upper back.
Overall, about 25% of the control group indicated some pain, and 80% of the hEDS or HSD group had frequent or continuous widespread pain.
“This variation in pain appearance reflects clinical reality and indicates that adolescents with HSD/hEDS, even when compared to a control group with low pain, show significantly different outcomes,” the researchers wrote.
A future comparison with patients with only widespread pain may reveal “whether widespread pain becomes the predominant issue requiring attention, despite HSD/hEDS being the initial cause,” the scientists wrote.
On questionnaires, patients showed significantly lower scores for fatigue, meaning they had more fatigue. Patients also had higher scores for pain catastrophizing, depression, and anxiety. Pain catastrophizing is the tendency to magnify the threat of a pain stimulus.
“Our findings imply that cognitive-emotional factors may influence pain sensitivity among adolescents with HSD/hEDS,” the team wrote.
“These results indicate, when creating a treatment plan for patients with HSD/hEDS, that pain should not be considered solely as caused by peripheral impulses, but rather as a phenomenon that is influenced by different biopsychosocial factors in which central mechanisms also need to be taken into consideration,” the scientists added.
The investigators noted their study did not achieve its target sample size, so results should be interpreted with caution. “Larger studies need to be conducted to obtain generalizable results,” they wrote.
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