Diagnosing Ehlers-Danlos Syndrome
Symptoms and Diagnosis
Ehlers-Danlos Syndrome affects all races and ethnic groups. The diagnosis of EDS is made upon clinical grounds first, skin hyperelasticity, easy bruising, dystrophic scarring, and joint hypermobility are the cardinal symptoms, which may be present in different combinations and with variable severity. A full medical and family history should be taken. Diagnosis is often impossible to make in infants and small children as abnormal joint hypermobility and skin elasticity are difficult to recognize, however, babies may present as floppy infants. In children, joint hypermobility and hypotonia may cause delayed motor development, problems with walking e.g. frequent stumbling, and mild motor disturbances often thought to be clumsiness. Other characteristics can be mitral valve prolapse, hernia, rectal prolapse, gastrointestinal diverticula, blue sclerae and easy inversion of the upper eyelid.
For Classic, Vascular, Dermatosparaxis and Kyphoscoliosis EDS types there are laboratory tests which may confirm or exclude the diagnosis. For EDS types Hypermobility and Arthrochalasia there is no biochemical marker and a diagnosis is made on the basis of symptoms and family history. Electron microscopic examination of a skin biopsy may reveal changes in the structure of collagen fibers, which is not specific but can be used as a diagnostic criterion for EDS in the absence of a biochemical marker. In some patients an unequivocal classification cannot be made. Coagulation tests are normal.
Classic and Hypermobility Types
These two types of Ehlers-Danlos Syndrome comprise 90% of all cases.
Joint hypermobility is assessed by means of a method adapted from one first described by Carter and Wilkinson (1967). The patient scores one point for the ability to perform each of the following tests, therefore giving a score of up to nine. For comparison, most healthy subjects score 0-1, a score of 5 is needed for a diagnosis of hypermobility.
- Passive dorsiflexion of each little finger beyond 90 degrees with the forearm flat on a table.
- Passive opposition of each thumb to the flexor aspect of the forearm.
- Hyperextension of each knee beyond 10 degrees.
- Hyperextension of the elbow beyond 10 degrees.
- Forward flexion of the trunk so that the palms of the hands rest easily on the floor.
Texture and Characteristics
The skin has a soft velvety consistency, similar to wet chamois leather, it extends easily and snaps back after release. Some other skin signs are: mild epicanthic folds; elevated cutaneous nodules at the knees and elbows and subcutaneous fatty cysts. Lacerations of the skin may follow even mild trauma. Wound healing is poor and ‘cigarette paper’ scars are common. Skin can be discolored over the elbows, knees and shins and hematoma may be present.
The degree of skin extensibility varies from patient to patient, and between various sites of the body, the skin of the ventral aspect of the forearm is lifted at a point midway between the elbow and the wrist joint. The distance to which this skin fold can be stretched without causing discomfort is measured in centimeters. An extensibility score (from 0-5) is calculated on the following basis:
Less than 4 cm, 0.5 cm, 2.7 cm = 4
More than 4 cm, 1.6 cm, 3.8 cm = 5
A score of one was given for each of 5 bony points that bore more than 2 scars which were over 2 centimeters in length. The areas which were assessed are both elbows, both knees, and the forehead.
The severity of the bruising tendency is scored 0-5 on the following basis:
0 no history or clinical history of bruising.
1 a history of mild bruising, but no clinical evidence.
2 A history of moderate bruising, or of bleeding, with or without positive clinical findings.
3 Moderate bruising found on clinical examination.
4 Marked bruising found on clinical examination
This facet of the condition is not easy to assess.
There are approximately 6 different types of EDS which have been distinguished. Differences within types may reflect inter/intra familial variability or genetic heterogeneity. The present classifications based on a combination of clinical, genetic, and biochemical criteria will be revised, as molecular defects become clearer.