Let's learn about the Ehlers-Danlos syndromes

Let's learn about the Ehlers-Danlos syndromes

What are the Ehlers-Danlos syndromes?

The Ehlers-Danlos syndromes (EDS) are a group of thirteen individual genetic conditions, all of which affect the body's connective tissue. Connective tissue lies between other tissues and organs, keeping these seperate whilst connecting them, holding everything in place and providing support, like the mortar between bricks. In EDS, a gene mutation causes a certain kind of connective tissue- the kind will depend on the type of EDS but usually a form of collagen- to be fragile and stretchy. This stretchiness can sometimes be seen in the skin of someone with EDS; individuals with the condition may also be able to extend their joints further than is usual- this is known as being hypermobile, bendy or double-jointed. As collagen present throughout the body, people with EDS tend to experience a range of symptoms, most of them less visible than the skin and joint differences. These are complex syndromes affecting many systems of the body at once, despite this EDS is often an invisible disability. Symptoms commonly include, but are not limited to, long-term pain, chronic fatigue, dizziness, palpitations and digestive disorders. Such problems and their severity vary considerably from person to person, even in the same type of EDS and within the same family.

Types of EDS

The Ehlers-Danlos syndromes are a group of genetic connective tissue disorders which are currently classified in a system of thirteen types. Despite this grouping and their common name, each type is a distinct condition caused by a different type of gene mutation. This means that a child cannot inherit a different type of EDS to the one their parent has. It also means that one type cannot later turn into another type just because you have one- they are simply not connected. It is also extremely unlikely that one person would have more than one type, given the rarity of most of these illnesses.

Recently some of the criteria used to diagnose the Ehlers-Danlos syndromes and some of the terminology describing them changed, in order to relfect scientific research from the past twenty years. The 2017 EDS international classification recognises thirteen types of EDS and defines for the first time some related conditions, the hypermobility spectrum disorders (HSD) which have similar symptoms to hypermobile EDS (hEDS). The term joint hypermobility syndrome (JHS) is no longer used. 

The most common type of EDS is thought to be the hypermobile type (formerly known as the hypermobility type or type 3) although the exact prevalence of this condition is not currently known. The medical literature states that it affects 1 in 5,000 people however this statistic is based on research that is out of date and hEDS/HSD frequently go undiagnosed or are misdiagnosed as other conditons, HSD and possibly hEDS are likely to be common. The classical and vascular type are rare, with other types being rarer still. It is probable that all the types are underdiagnosed to some degree.

Diagnosing EDS

For many people with Ehlers-Danlos syndrome the journey to diagnosis will have been a long and convoluted one. Poor awareness of the condition amongst medical professionals means that it can go undiagnosed. It is common to be wrongly diagnosed with another condition first in an effort to find answers. Misdiagnoses of fibromyalgia and ME/chronic fatigue syndrome, and the label of irritable bowel syndrome when someone has digestive problems, are common. Typically people will wait years or decades for a diagnosis of EDS, if they get one at all. Yet diagnosis is very important. The Ehlers-Danlos syndromes are genetic and are passed down from parent to child in different ways according to the type in question (some follow a dominant pattern of inheritance others recessive). A precise diagnosis gives information about the risk of passing the condition on in a family and about prognosis. Diagnosis guides proper management of the syndromes, which includes learning to avoid activities which might cause irreversible joint damage as well as unhelpful treatments such as inappropriate medication. For these reasons the prognosis is likely to be better if someone is diagnosed at a younger age. Many with EDS would also argue that diagnosis is important for psychological reasons, encouraging motivation and acceptance. Most would also agree it is easier to tackle something when you know what you're dealing with. The diagnosis pathway differs according the type of EDS suspected, with a different route for hEDS/HSD to that for the rare types.

Understanding hypermobile EDS

Hypermobile EDS, which used to be known as the hypermobility type or type 3, is thought to be the common genetic connective tissue disorder. There is no up to date research to tell us exactly how frequently it occurs. It can be inherited from a parent with the same faulty gene, alternatively someone can be born with a new mutation so that the condition is occuring in their family for the first time. 

Recently some changes were made to the way hypermobile EDS is diagnosed. There is no test for hEDS, so diagnosis involves looking for joint hypermobility, signs of faulty connective tissue throughout the body (eg skin features, hernias, prolapses), a family history of the condition, and muskeloskeletal problems (eg. long-term pain, dislocations). There are many associated symptoms and disorders which don't form part of the formal criteria and which do not directly result from joint, hypermobility, for instance orthostatic tachycardia, digestive disorders, pelvic and bladder dysfunction, and anxiety disorders. These are often more detrimental to quality of life than the joint symptoms. 

Many people do not fully meet the new diagnostic criteria for hEDS but their hypermobility still causes problems for them. They may experience pain and dislocations, have poor sense of where their joints are without looking, be prone to injury, have curvature of the spine, and degenerative joint and bone disease. These people may also have many of the non-musculoskeletal disorders associated with hEDS, but they do not quite 'qualify' for hEDS. After other possible conditions are excluded, a diagnosis of hypermobility spectrum disorder may be made here.

Hypermobile EDS

People with hEDS may have:

  • joint hypermobility
  • loose, unstable joints that dislocate easily
  • joint pain and clicking joints
  • extreme tiredness (fatigue)
  • skin that bruises easily
  • digestive problems, such as heartburn and constipation
  • dizziness and an increased heart rate after standing up
  • problems with internal organs such as mitral valve prolapse or organ prolapse
  • problems with bladder control (stress incontinence)

Currently there are no tests to confirm whether someone has hEDS. The diagnosis is made based on a person's medical history and a physical examination. 

Classical EDS

Classical EDS (cEDS) is less common than hypermobile EDS and tends to affect the skin more.

People with cEDS may have:

  • joint hypermobility
  • loose, unstable joints that dislocate easily
  • stretchy skin
  • fragile skin that can split easily, especially other the forehead, knees, shins and elbows
  • smooth and velvety skin that bruises easily
  • wounds that are slow to heal and leave wide scars
  • hernias and organ prolapse

Vascular EDS

Vascular EDS (vEDS) is a rare type of EDS and is often considered to be the most serious. It affects the blood vessels and internal organs, which can cause them to split open and lead to life threatening bleeding. 

People with vEDS may have:

  • skin that bruises very easily
  • thin skin with visible small blood vessels especially on the upper chest and legs
  • fragile blood vessels that can buldge or tear, resulting in serious internal bleeding
  • a risk of organ problems, such as the bowel tearing, womb tearing (in late pregnancy) and partial collapse of the lung
  • hypermobile fingers and toes, unusual facial features (such as thin nose and lips,large eyes and small earlobes), varicose veins and delayed womb healing

Kyphoscoliotic EDS

Kyphoscoliotic EDS (kEDS) is rare. People with kEDS may have:

  • curvature of the spine- this starts in early childhood and often gets worse in teenage years
  • joint hypermobility
  • loose, unstable joints that dislocate easily
  • weak muscle tone from childhood (hypotonia)- this may cause a delay in sitting and walking or difficulty walking if symptoms get worse
  • fragile eyes that can easily be damaged
  • soft, velvety skin that stretches, bruises easily and scars. 

Source- physiotherapy and self management- the ehlers-danlos support uk

ehlers danlos syndromes NHS

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