What is HSD?

Hypermobility Spectrum Disorders (HSD)

Hypermobility spectrum disorders (HSD) are a group of conditions related to joint hypermobility (JH). HSD are diagnosed after other possible conditions have been excluded, such as any of the Ehlers-Danlos syndromes (EDS) including hypermobile EDS (hEDS).

HSD, just like hEDS, can have significant effects on our health. Whatever the problems that arise, whatever the diagnosis, it is important that these effects are managed appropriately and that each person is treated as an individual. HSD and hEDS can be equal in severity, but more importantly, both need similar management, validation, and care.

The Mechanics

Joint hypermobility is a term to describe the capability of joints to move beyond the normal range of motion. It can exist by itself or be a part of a more complex diagnosis. For some, joint hypermobility may be localized (LJH) to a few joints. Those with joint hypermobility in five or more joints are described as having generalized joint hypermobility (GJH). Unlike LJH, GJH is more often something we’re born with and possibly inherited, although acquired forms of GJH exist (training such as dance, widespread inflammatory or degenerative diseases of the joints, musculoskeletal tissues, and nerves).

There are other types of JH. Peripheral joint hypermobility is a form that affects the hands and/or feet only. It is common in infants, toddlers, and children, in whom it is usually mild or has no serious effect. Another is proposed for older adults who have progressively lost JH, called historical joint hypermobility.

Joint hypermobility ranges from asymptomatic JH and GJH through to hEDS as part of the EDS. Along that continuum fall localized general spectrum disorder (L-HSD), peripheral hypermobility spectrum disorder (P-HSD), historical hypermobility spectrum disorder (H-HSD), and generalized hypermobility spectrum disorder (G-HSD).

  • Generalized (joint) HSD (G-HSD): GJH objectively assessed (e.g., by the Beighton score) plus one or more secondary musculoskeletal manifestations identified below. The pattern and severity of the musculoskeletal involvement should be carefully assessed in order to explore the possibility full-blown hEDS.
  • Peripheral (joint) HSD (P-HSD): JH limited to hands and feet plus one or more secondary musculoskeletal manifestations.
  • Localized (joint) HSD (L-HSD): JH at single joints or group of joints plus one or more secondary musculoskeletal manifestations regionally related to the hypermobile joint(s).
  • Historical (joint) HSD (H-HSD): self-reported (historical) GJH with negative Beighton score plus one or more secondary musculoskeletal manifestations. Physical examination aimed at excluding the alternative diagnoses of G-HSD, P-HSD, and L-HSD as well as other rheumatologic conditions is mandatory.

The Spectrum of Joint Hypermobility

TypeBeighton scoreMusculoskeletal
involvement
Notes
Asymptomatic GJH      PositiveAbsent 
Asymptomatic PJHUsually negativeAbsentJH typically limited to hands and/or feet
Asymptomatic LJHNegativeAbsentJH limited to single joints or body parts
G-HSDPositivePresent 
P-HSDUsually negativePresentJH typically limited to hands and/or feet
L-HSDNegativePresentJH limited to single joints or body parts
H-HSDNegativePresentHistorical presence of JH
hEDSPositivePossible 

Secondary Musculoskeletal Manifestations

Joint hypermobility can be symptomless apart from the unusual mobility, but there is a series of other symptoms that result from that mobility. These should be evaluated for a diagnosis of HSD (and treated, of course).

Trauma

Macrotrauma includes dislocation, subluxations, and connective soft tissue damage (ligaments, tendons, muscles). It can cause acute pain and loss of joint function. Microtrauma are injuries too small to be noticed as they happen. Over time, they may make a person susceptible to recurrent or persistent pain, and possibly early joint degeneration like osteoarthritis.

Chronic Pain

Occasional, recurring pain is a natural result of the trauma, but chronic pain can develop—perhaps because of repeated triggering of pain receptors in the tissues, or increased sensitivity to pain (hyperalgesia), and perhaps because of an impaired connective tissue function.

Disturbed Proprioception

Proprioception—the sense of the relative position of parts of the body and how much effort is needed for movement—can be reduced. Not understanding where our joints are and how much muscle strength it takes to use them can lead to a cycle that increasingly limits our abilities to manage everyday life.

Other Musculoskeletal Traits

Those with GJH often have other minor musculoskeletal physical traits, which may be the result of the interactions between “softer” musculoskeletal tissues and mechanical forces during growth. These include flat feet (flexible type), misaligned bones in the elbow and big toes, mild to moderate scoliosis (side to side curvature of the spine), kyphosis (outward curvature) of the upper spine and lordosis (inner curvature) of the lower spine. There may be an indirect association with mild reduced bone mass as a result of many factors—lack of proprioception, muscle weakness, and the resulting reduced activity.

Associated Problems Not Based in the Musculoskeletal System

There are quite a few issues that are not the direct result of the mechanics of joint hypermobility. These associations are very real; they seriously affect quality of life and they need to be managed as part of treatment. The strongest (but not only) associations noted so far are anxiety disorders, orthostatic tachycardia, and low blood pressure, a variety of functional gastrointestinal disorders, and pelvic and bladder dysfunction. These additional problems need to be evaluated and treated when an HSD is diagnosed.

 

What can I do now?

The Ehlers-Danlos Society members are sharing information online and learning from each other in ways that were impossible not very long ago.

Connect with others by visiting The Ehlers-Danlos Society’s

Learn more about living with HSD/EDS by visiting The Ehlers-Danlos Society’s