Connective tissue damage is severe when EDS meets joint disease
Spondyloarthritis can worsen fragile connective tissue in EDS patients
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New research shows that the complex, overlapping symptoms of Ehlers-Danlos syndrome (EDS) and spondyloarthritis (SpA) are linked to pronounced physical changes in the body’s connective tissue.
A study using ultrasound scans found that people living with both conditions experience significantly greater thickening, or densification, of a deep tissue layer covering the lower back and trunk muscles — the thoracolumbar fascia (TLF) — compared to those with EDS alone.
These findings suggest that the inflammation caused by SpA may worsen the connective tissue alterations already present in EDS, underscoring the importance of doctors considering the coexistence of SpA when assessing EDS patients.
The challenge of co-existing conditions
Diagnosing “both conditions when they co-exist can be particularly complex — even with ultrasound imaging,” but the study “identified ultrasonographic differences between groups, particularly increased thoracolumbar fascia (TLF) densification in the SpA [plus] EDS group,” researchers wrote.
The study, “Connective tissue changes in Ehlers–Danlos syndromes with and without axial spondyloarthropathy,” was published in the Journal of Ultrasound.
EDS is a group of disorders that affect the connective tissue, which provides structure to joints, skin, blood vessels, and other tissues and organs. People with EDS typically have overly flexible joints and fragile, unusually stretchy skin, among other symptoms.
SpA refers to a group of inflammatory disorders characterized primarily by inflammation in the spine and other joints, resulting in symptoms such as chronic back pain, joint stiffness, and fatigue.
The inflammatory disorder is reported in about 22% of EDS cases. However, due to the overlapping symptoms, their diagnosis is often challenging, causing delays ranging from six to 10 years.
Fascia is a thin layer of connective tissue that wraps around and supports nearly every structure in the body, acting as a shock absorber to help muscles move smoothly and stabilize joints during motion.
Previous studies have shown that individuals with hypermobile EDS, the most common type of EDS, experience fascia thickening, which leads to reduced gliding and also pain. Similar changes may contribute to symptoms in SpA.
However, “to date, no studies have specifically examined connective tissue characteristics in individuals with both EDS and SpA,” the researchers wrote.
Ultrasound reveals TLF densification
In the study, an international team of researchers hypothesized that having both EDS and SpA would lead to more fascia thickening. To test this, they used ultrasound scans to evaluate connective tissue alterations in 37 individuals with EDS (mean age, 40; 36 women), 23 of whom also had SpA (EDS-SpA group).
The team specifically looked at the TLF and the sternocleidomastoid (SCM) fascia, which covers a neck muscle. They found that the TLF was significantly thicker in the EDS-SpA group when compared with the EDS group (median 5.6 vs. 4.4 mm). However, the SCM was not significantly different between the groups.
Biologics, including anti-TNF treatments, were used more often in the EDS-SpA group (34.8%) compared to the EDS-only group (7.1%). Biologics are therapies derived from living organisms, and anti-TNF therapy is not a standard treatment for EDS but is sometimes used for co-occurring inflammatory conditions.
Participants receiving anti-TNF therapy showed a significantly greater TLF thickness than those not on biologics (median 5.7 mm vs. 5 mm), a finding that, according to the researchers, is likely due to inflammation, rather than simply having the disease longer.
TLF thickness “is significantly greater in patients with both conditions, supporting the hypothesis that inflammation associated with SpA may exacerbate connective tissue alterations already present in EDS,” the researchers wrote.
“While [ultrasound] may not distinguish SpA from EDS in individual patients, it provides useful insight into the extent of fascial remodeling and may complement clinical evaluation when overlapping features are suspected,” the team concluded.
