Juvenile Hypermobility Syndrome
Joint hypermobility is the term used when a joint has an unusually large range of movement. The numbers of joints affected vary although the knees, elbows and fingers are the most commonly affected, along with flattening of the arches of the feet. People with hypermobility are particularly supple and able to move their limbs into positions that other people find impossible. There is a huge variation in degree of hypermobility and for some children it may not cause any problems. However, for others they may experience pain and discomfort, especially after being active, they may easily fatigue and have reduced co-ordination due to joint laxity. In these cases the condition "Benign Juvenile Hypermobility Syndrome" may be diagnosed.
Joint hypermobility is often hereditary (i.e. it runs in families) and is the result of the connective tissue between the joints, skin, tendons and ligaments being more flexible than average. As a result the joints can move past the usual range of movement. These children may be more vulnerable to injury and find that their muscles have to work harder to move their body or to keep a good posture or a position. Activities such as writing will therefore also be harder work.
In addition, these children often have low muscle tone (the amount of tension or resistance to movement in a relaxed muscle), which may result in reduced muscle strength. This will lead to further difficulties with movement and posture.
Occasionally, joint hypermobility is part of a rare and more serious condition, such as:
- Osteogenesis imperfecta – a condition that affects the bones
- Marfan syndrome – a condition that affects the blood vessels, eyes and skeleton
- Ehlers-Danlos syndrome – a condition that causes stretchy skin and the skin to bruise easily
It is considered that 3 in every 10 people have some degree of hypermobility and that more females are affected (due to hormones which increase flexibility). Although joints are known to become stiffer as children reach puberty, in some cases the hypermobility and resultant symptoms continue into adult life.
What parents and children may report:
- "double jointed" or can contort their limbs into strange shapes
- Physical activity may exacerbate pain of the affected joints
- Joint or muscle pain at night
- Fatigue and lack of stamina
- Muscle cramps
- Prone to injury e.g. sprains, strains, dislocations
- Poorly co-ordinated and may be considered "clumsy"