Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

Featured on Channel NewsAsia

Ehlers-Danlos Syndrome

Basics
Description
  • Ehlers-Danlos syndrome is a family of disorders involving abnormal collagen that produces connective tissue laxity, with many resultant abnormalities in the skeleton, vasculature, eyes, and other systems.
    • At least 11 subtypes of Ehlers-Danlos syndrome have been identified, with varying patterns of inheritance and genetic causes.
    • The age at diagnosis varies from infancy to adulthood.
  • Classification:
    • Type I: Gravis (classic):
      • Aneurysms
      • Rupture of hollow viscus
      • Skin hyperextensibility
      • Bruising
      • Pigmented areas
      • Hernias
    • Type II: Mitis:
      • Similar manifestations but milder
    • Type III: Benign hypermobility syndrome:
      • Laxity
      • Joint dislocations
      • Mitral valve prolapse
      • Positive family history
    • Type IV: Ecchymotic:
      • Thin skin
      • Normal joints
      • Aneurysms
      • Viscus rupture
    • Type V: X-linked:
      • Intramuscular hemorrhagia
      • Floppy baby characteristics
    • Type VI: Ocular-scoliotic
    • Type VII: Arthrochalasis multiplex congenital:
      • Extreme joint laxity
      • Short stature
      • Hip dislocations
    • Type VIII: Periodontosis (progressive periodontal disease)
    • Type IX: Occipital horns and skeletal dysplasia
    • Type X: Platelet dysfunction
    • Type XI: Familial joint laxity (patellar and hip dislocation)
General Prevention
  • Prevention of cardiovascular and bleeding emergencies should be the goal of treatment.
  • Reduction in frequency of joint dislocations also may be possible.
Epidemiology
Incidence
  • Overall, males and females are affected equally.
  • Incidence is impossible to calculate accurately because of the numerous forms of this disorder and their varying degrees of severity.
Risk Factors
A positive family history of the syndrome or of its major manifestations is a risk factor.
  
Genetics
  • Types I, IV, VIII, and XI are autosomal dominant.
  • Types V and IX are X-linked.
  • The remainder are autosomal recessive in transmission.
  • Many patients present as having a new mutation without a family history.
Etiology
  • Type IV, the ecchymotic variety, is secondary to a disorder of type III collagen.
  • Type VI (ocular-scoliotic) is the best characterized.
    • It is caused by a defect in lysine hydroxylase that affects collagen.
    • This change results in decreased collagen cross-linking.
  • Type VII (arthrochalasis multiplex congenital) is secondary to a defect in type I collagen.
  • Type X (with platelet dysfunction) also results from a defect in type I collagen.
Diagnosis
The diagnosis is made by a medical geneticist on a clinical basis, with verification in some types by use of molecular testing.
 
Signs and Symptoms
  • Signs:
    • Lax skin
    • Joint hypermobility
    • Joint instability
    • Scoliosis
    • Ability of some affected persons to perform skeletal contortions impossible for nonaffected persons
  • Symptoms:
    • Multiple joint pains
    • Vague musculoskeletal pains
Physical Exam
  • Record height.
  • Observe the proportions of the skeleton.
  • Systematically measure joint ROM.
  • Note the ability to hyperextend the fingers and the knees.
  • Check the shoulders, elbows, and knees for stability.
  • Feel the quality of the skin.
  • Note any bruising.
  • Pursue an ocular examination if any symptoms of deficit are present.
  • Observe the spine for kyphosis.
  • Conduct a forward-bend test for scoliosis.
Tests
  • Molecular testing is available to confirm many, but not all, types of Ehlers-Danlos syndrome.
  • An experienced genetics laboratory should be consulted.
Imaging
  • Imaging of the heart and aorta should be obtained periodically for patients with type I and type IV disorders.
  • Plain radiographs should be obtained when physical examination suggests scoliosis, kyphosis, or spondylolisthesis.
Pathological Findings
  • Light microscopic examination of fibroblasts of the skin shows irregular collagen fibers.
  • Gross examination of the aorta may show dissecting aneurysms in type I, myxomatous changes in the cardiac valves, and redundant chordae tendineae.
Differential Diagnosis
  • Marfan syndrome also is characterized by laxity of major joints, but it is rarely symptomatic, and it has well-defined diagnostic criteria.
  • Larsen syndrome also presents with multiple joint dislocations, but contractures also are present, and cervical kyphosis is common.
  • Cutis laxa and pseudoxanthoma elasticum also should be ruled out in patients with predominant skin findings.
Treatment
General Measures
  • Specialist referral for the systems listed earlier is indicated when problems are manifested by the patient.
  • One should use caution when recommending surgery for joint instability because the failure rate is higher than normal.
  • Surgical treatment should not be undertaken in Ehlers-Danlos syndrome unless symptoms are severe.
  • Fusion of joints may be necessary to provide stability.
Special Therapy
Physical Therapy
  • Muscle conditioning may ameliorate some of the symptoms of joint instability, even if these symptoms are not eliminated.
  • Physical therapy also should be helpful in educating patients about how to decrease the frequency of joint dislocations.
Surgery
  • Fusion for scoliosis is indicated if curves are >45° (approximately) and the patient’s medical condition is otherwise satisfactory.
  • Physical activity usually is encouraged, but should be tailored to the patient and focused on low-impact sports.
Follow-up
Disposition
Issues for Referral
The best specialist for the routine follow-up of patients with Ehlers-Danlos syndrome is usually a medical geneticist.
 
Prognosis
The listed complications lead to a moderate decline in the mean life expectancy.
 
Complications
  • Sudden death from cardiovascular complications
  • Osteoarthritis of joints
  • Visual deficits
Miscellaneous
Codes
ICD9-CM
756.83 Ehlers-Danlos syndrome
 
Patient Teaching
  • Genetic counseling should be offered.
  • Understanding the nature of any cardiovascular abnormality should be taught, in case of medical emergency.
  • Contact or high-impact sports should be discouraged.
Activity
Activity is encouraged but should be limited to noncontact sports that do not cause pain.
 
FAQ
Q: Are braces helpful in Ehlers-Danlos syndrome?
A: They may be in some cases, but in others they produce more inefficient movement. A trial can help determine applicability.
 
Q: Is any medication available that can improve the tissue laxity?
A: No, not at this time.
 
Q: How does one deal with the pain felt by some patients with Ehlers-Danlos syndrome?
A: If standard measures fail, referral to a pain specialist may be helpful.

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