Connective tissue changes in Ehlers–Danlos syndromes with and without axial spondyloarthropathy

Purpose: Ehlers–Danlos Syndromes (EDS) are a group of connective tissue disorders characterized by joint hypermobility, skin hyperextensibility, and tissue fragility. The co-ocurrence of spondyloarthritis (SpA), an inflammatory arthritis in individuals with EDS, presents unique diagnostic and therapeutic challenges due to overlapping clinical features. This study aimed to investigate the connective tissue characteristics in patients with both EDS and SpA. Methods: Twenty-three participants with EDS and co-occurring SpA (SpA + EDS), and fourteen participants with EDS without SpA (EDS-only) were evaluated using ultrasound imaging and strain elastography to assess the thickness and stiffness of the sternocleidomastoid muscle and thoracolumbar fascia. Data were analyzed using descriptive and inferential statistical methods. Results: A statistically significant increase in thoracolumbar fascia thickness was observed in the SpA + EDS group compared to the EDS-only group (p = 0.002). The median thickness in the SpA + EDS group was 5.6 mm (IQR: 2.0 mm), versus 4.4 mm (IQR: 1.7 mm) in the EDS-only. Conclusion: Co-occurring SpA poses diagnostic challenges due to its clinical overlap with EDS. The increased thoracolumbar fascia thickness observed in SpA + EDS patients, while also present to a lesser degree in EDS-only participants, suggests that fascial remodeling may reflect overlapping inflammatory and mechanical processes. Ultrasonography may thus serve as a complementary tool to monitor connective tissue changes in this population.