UNDERSTANDING HYPERMOBILE EHLERS-DANLOS SYNDROME & HYPERMOBILITY SPECTRUM DISORDER
Terminology update 2017
'For patients and colleagues not familiar with the classification and terminology update that occurred in 2017, the joint hypermobility syndrome (JHS) diagnostic criteria covered a wide group of patients some of whom had signs and symptoms that might equally be described as the hypermobile variant of Ehlers-Danlos syndrome (EDS-HM). As such, some confusion arose over the use of JHS/EDS-HM co-terminology.
The 2017 international criteria for the hypermobile variant (hEDS) were developed to address this, give clarity as to the diagnosis of hEDS, and also allow opportunity for more focused basic science and clinical research including assessment of treatment outcomes.
The term JHS has been dropped. Those individuals with hypermobility-related problems that do not have hEDS; or any other heritable disorder of connective tissue; or other syndromic or secondary myopathic, neuropathic, or traumatic cause for hypermobility / joint instability are now given the diagnosis of hypermobility spectrum disorder (HSD).
There is a ‘spectrum’ of presentations ranging from asymptomatic hypermobility to a diagnosis of hEDS. This does not infer any greater severity at one end compared to the other; a person with HSD can have severe problems, and a person with hEDS minor problems.
'Where a patient is placed within the spectrum does not necessarily represent the ‘severity’ of symptoms experienced, it represents the ‘range’ of symptoms experienced. Indeed, one person's hypermobile Ehlers-Danlos syndrome joint pain may be less severe than another's hypermobility spectrum disorder joint pain. The overall spectrum isn't strictly linear; from least to most severe, it represents the range of symptoms seen in patients; from single joint issues through to the ‘syndrome of disorders’ seen in hEDS. Symptoms of both disorders can be equal in severity and, importantly, need similar management, validation and care.
(Wicks D. and Hakim A.J. 2017)
From a clinical perspective for the majority of concerns that arise across the spectrum, whether HSD or hEDS, the treatment approaches are the same at present. Both are associated with particular patterns of complex concerns, though fortunately neither with major life threatening conditions like vascular or bowel rupture, such as that seen in the more rare variants of EDS.'
(Hakim A. 2018 - Personal correspondence -Suggested explanatory footnote)
International Classification update 2017
Since the Villefranche Classification, many rarer types of EDS have been identified, and the clinical description of some types in medical literature have expanded considerably. The clinical description of the hypermobile type of EDS in particular has grown extensively, now encompassing features such as persistent pain, persistent fatigue, cardiovascular autonomic dysfunction and anxiety amongst other associated symptoms (Castori M. et al 2017).
In May 2016, a group of around 250 world renowned experts met in New York with the primary goal of redefining the diagnostic criteria for all the types of Ehlers-Danlos syndrome, and developing best practice clinical guidelines for diagnosis and management.
During this process, a systematic review of available data relating to all the symptoms and conditions that arise either as direct complications of hEDS or which might have direct associations with hEDS was carried out. This, combined with clinical experience accumulated by participating experts such as Castori, Hakim, Seneviratne, Francomano, Malfait, Tinkle, Chopra, Levy et al, as well as many ‘patient experts’, depicted the hypermobile type of Ehlers- Danlos syndrome (known synonymously at that time as joint hypermobility syndrome), as being a more complex clinical picture than had previously been described in preceding classifications, with ‘reverberations in practically all organs and systems.’
A unified set of diagnostic criteria is presented
In March 2017, the International Consortium on Ehlers-Danlos syndrome produced the new nosology for the Ehlers-Danlos syndromes (EDS), identifying 13 different types of EDS (to view these, click here). This included the Framework for the Classifcation of Joint Hypermobility and Related Conditions and Hypermobile Ehlers-Danlos Syndrome Clinical History and Natural History. They proposed a new, unified set of diagnostic criteria, designed to enable more precise diagnosis and lead to better treatment for patients (3/ Ehlers-Danlos Society 2017). The criteria is intended to define a more uniform set of observable characteristics shared among patients, and to more accurately reflect the original description of the disorder within the Classification (Castori M. et al 2017 / Tinkle B. et al 2017).
Those individuals with hypermobility-related problems that do not meet the criteria for hEDS or any other heritable disorder of connective tissue, are now given the diagnosis of hypermobility spectrum disorder (HSD) (Tinkle B. et al 2017, Castori M. et al 2017).
Associated disorders - the disparity between what we ‘know’ and what we can actually prove at this time
Whilst many advances in classification were undoubtably made, and an ‘association’ with hEDS and a number of disorders was evidenced both through clinical experience and the systemic review of available literature, insufficient research currently exists to prove that these disorders are directly caused by having hEDS. Also, for a number of them it has not yet been shown exactly how common they are in the whole hEDS population compared to the general population, or other groups of people with chronic medical conditions (6/HMSA 2017). More funding and research is urgently required in order to evidence beyond doubt the multi-system manifestations that experts are recognising daily in their patient clinics, i.e there is a significant difference between what we ‘know’ and what can actually be proved.
This disparity means that, for now at least, some disorders, which many had hoped to see included, will not form part of the criteria for hEDS, although their ‘significant association’ is recognised in the classification papers, which are to be reviewed every two years and updated where necessary. These disorders include, but are not limited to:
• Functional gastrointestinal disorders
• Cardiovascular autonomic dysfunction (including postural orthostatic tachycardia)
• Sleep disturbance
• Fatigue
• Anxiety and depression
• Tethered cord and chiari malformation
• Mast cell activation syndrome
(Details of symptoms and manifestations that are included in the hypermobile type of EDS can be found by clicking here).
Highlighting the ‘gaps’ in research data is a small step forward in itself, as it assists researchers to target specific areas of interest/uncertainty. 'The evidence based signs and symptoms included in the classification will ensure an enhanced level of credibility and understanding of hEDS going forward, and enable progress to be made in research and management' (3/Ehlers-Danlos Society).
References:
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