Is there a diffference between HSD and hEDS?

Hypermobile Ehlers-Danlos Syndrome (hEDS) and Hypermobility Spectrum Disorders (HSD) are two conditions often linked by their association with joint hypermobility, where joints move beyond their normal range of motion. Despite their similarities, these conditions have distinct diagnostic criteria, associated symptoms, and potential complications. The challenge of differentiating between them has significant implications for patient care, diagnosis, and treatment.

What is Hypermobile Ehlers-Danlos Syndrome (hEDS)?

hEDS is one of the 13 subtypes of Ehlers-Danlos syndromes (EDS), a group of connective tissue disorders characterized by generalized joint hypermobility, skin hyperextensibility, and tissue fragility. Unlike other EDS subtypes, hEDS lacks a known genetic marker, making diagnosis primarily clinical. The 2017 International Classification of EDS set forth specific criteria for diagnosing hEDS, including the presence of generalized joint hypermobility (often assessed using the Beighton scoring system), specific clinical features like skin involvement and musculoskeletal complications, and the exclusion of other EDS subtypes and related conditions​​.

What are Hypermobility Spectrum Disorders (HSD)?

HSD, introduced in 2017, describes a range of conditions where joint hypermobility is present but the individual does not meet the criteria for hEDS or other types of EDS. HSD includes a broad spectrum, from asymptomatic joint hypermobility to more severe forms that involve pain, fatigue, and joint instability. It is further categorized based on the extent and location of hypermobility, including Generalized HSD (G-HSD), Peripheral HSD (P-HSD), Localized HSD (L-HSD), and Historical HSD (H-HSD)​.

Diagnostic Criteria: hEDS vs. HSD

The most significant difference between hEDS and HSD lies in their diagnostic criteria. hEDS requires a combination of generalized joint hypermobility, specific clinical features, and exclusion of other conditions. HSD is diagnosed when an individual exhibits joint hypermobility but does not fulfill the criteria for hEDS. This diagnostic distinction is crucial but also controversial. Some patients previously diagnosed with hEDS under older criteria now fall into the HSD category, which complicates their care, especially since HSD is not universally recognized in the medical community​​.

Symptom Overlap and Differences

Both hEDS and HSD share many symptoms, including joint pain, chronic fatigue, and gastrointestinal issues. However, research indicates that hEDS may present with more severe symptoms, particularly regarding pain, motricity problems, and bleeding. A 2021 study found that while hEDS patients tend to experience these symptoms more intensely, bone fragility, neuropathic pain, and symptoms of mast cell activation syndrome (MCAS) are equally prevalent in both hEDS and HSD. Despite these differences, long-term outcomes after coordinated physical therapy were similar, suggesting that hEDS and HSD may exist on a continuum rather than as entirely separate entities​.

Long-term Complications

Both hEDS and HSD can lead to significant long-term complications if not properly managed. People with hEDS are at a higher risk of developing early-onset osteoarthritis, recurrent joint dislocations, and chronic pain syndromes, with potential cardiovascular complications as well. In contrast, those with HSD may primarily face musculoskeletal issues, such as frequent sprains, joint instability, and chronic pain. Although HSD is often considered milder, it can still significantly impact an individual's quality of life​.

Management and Treatment

Managing hEDS and HSD typically involves a multidisciplinary approach, focusing on symptom relief and improving the patient’s quality of life. Physical therapy plays a critical role in managing both conditions, with studies showing no significant differences in patient-reported outcomes after one year of coordinated care. This suggests that similar treatment strategies can be effective for both conditions, despite the differences in their diagnostic criteria. Patient education and self-management are also crucial, emphasizing the importance of protecting joints, managing pain, and maintaining physical activity without causing harm​.

The Controversy Surrounding hEDS and HSD

The definitions of hEDS and HSD, as well as the differences between them, are subjects of ongoing debate. Science, as an ever-evolving discipline, constantly refines our understanding of these conditions. The 2017 criteria were intended to bring clarity, but they have also been criticized for being overly stringent. Many patients who would have been diagnosed with hEDS under previous criteria now fall under the HSD category, leading to significant implications for their care. One major issue is that HSD is not universally recognized in the medical community; many countries still do not have an ICD-10 code for HSD, which complicates its recognition in medical records and insurance systems​​.

This gap forces healthcare providers to use alternative diagnoses, such as Undifferentiated Connective Tissue Disorder or Benign Joint Hypermobility Syndrome, which can lead to inconsistencies in care and add confusion to the patient’s medical journey. Additionally, the lack of recognition for HSD in some healthcare systems, such as Italy’s public healthcare system, creates significant barriers to care, exacerbating the financial and psychological burden on patients​​.

The Need for Broader Diagnostic Criteria

Given these challenges, some experts argue for expanding the diagnostic criteria for hEDS to include more patients who currently fall under the HSD umbrella. This expansion could improve access to care and support, facilitate more extensive research, and ultimately enhance our understanding of these conditions. Broader criteria would also help in conducting larger studies, which could yield more robust findings and accelerate progress in identifying genetic and molecular markers for diagnosis and treatment​.

Conclusion: Prioritizing Patient Well-being

While the debate over the definitions and diagnostic criteria for hEDS and HSD continues, it is essential to prioritize patient well-being. The ultimate goal should be to improve the quality of life for those affected by these conditions, whether through refining diagnostic criteria, developing new treatments, or expanding access to care. As our understanding of these complex conditions evolves, so too must our approach to supporting the individuals who live with them.

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