Travellers' thrombosis

• What is Travellers Thrombosis
• Statistics on Travellers Thrombosis
• Risk Factors for Travellers Thrombosis
• Progression of Travellers Thrombosis
• Symptoms of Travellers Thrombosis
• Clinical Examination of Travellers Thrombosis
• How is Travellers Thrombosis Diagnosed?
• Prognosis of Travellers Thrombosis
• How is Travellers Thrombosis Treated?
• Travellers Thrombosis References

What is Travellers Thrombosis

Travellers thrombosis may be referred to as venous thromboembolism (VTE), deep vein thrombosis (DVT) or commonly in the media as economy class syndrome. It refers to the development of a blood clot in the deep veins, most commonly in the lower legs and is meant to be associated with prolonged travel periods. These clots have the capacity to travel to various areas of the body such as the lungs (causing a pulmonary embolism or ‘PE’), therefore compromising blood flow in that region.

Statistics on Travellers Thrombosis

The true incidence of travellers thrombosis is not known. There have been over 200 documented cases of the problem in the past decade. Some studies have shown a greater risk of VTE associated with prolonged travel where others have shown no association. The recent media publication of travellers thrombosis has however urged more interest in this field.
Based on the limited data available on this subject only estimates of incidence can be made. Combining data from the most pertinent studies it is estimated that travellers thrombosis affects between 0-4 travellers per 10 000 travellers.

Risk Factors for Travellers Thrombosis

It is assumed that the risk factors for travellers thrombosis are the same for developing VTE in the absence of travel. These include:
 

• Increasing age above 40 years
• Pregnancy
• Former or current malignant disease
• Blood disorders leading to increased clotting tendency
• Inherited or acquired impairment of blood clotting mechanisms
• Some types of cardiovascular disease or insufficiency
• Personal or family history of DVT
• Recent major surgery or injury, especially to lower limbs or abdomen
• Oestrogen hormone therapy, including oral contraception
• Immobilisation for a day or longer
• Depletion of body fluids causing increased blood viscosityThe length of the journey is thought to be associated with an increased risk i.e. longer flights and journeys associated with periods of little movement are thought to increase the risk of developing travellers thrombosis.
  

  Progression of Travellers Thrombosis

  A VTE once formed, whether it is or is not associated with travel may have several fates:
   

• The clot may dissolve on its own due to fibrinolytic (clot dissolving) activity and cause no effect
• Embolisation (the clot breaks off and travels) may occur and the clot may travel to other areas of the bloodstream thus compromising blood flow there
• Complete vessel obstruction may occur where the thrombus is situated thus compromising blood flow from the original site of formation
  

  How is Travellers Thrombosis Diagnosed?

  A full blood count, Liver Function Tests, Urea and Creatinine are generally required to assess baselines levels of blood components and other enzymes.
  

  Prognosis of Travellers Thrombosis

  The general consensus is, however, the faster VTE associated with travel can be treated, the better.
  

  How is Travellers Thrombosis Treated?

  Initial stabilisation is first required. This involves supplemental fluid and oxygen. Surgical or vascular consultation is recommended. Anticoagulant therapy such as low molecular weight heparin may be used in suitable patients. Warfarin may then be administered.
  Vena Caval filters that filter thrombi in the body may be a long term solution if the patient has an extensive history of VTE.
  Prophylaxis of travellers thrombosis may include:
   

• Adequate mobilisation and regular lower leg exercises whilst travelling
• Good hydration
• Minimise alcohol consumption and sedative intake whilst travelling
• The use of compression stockings and aspirin may be indicated in high risk patients
  

  Travellers Thrombosis References

  [1] Cotran RS, Kumar V, Collins T. Robbins Pathological Basis of Disease Sixth Ed. WB Saunders Company 1999.
  [2] Kesteven PJL. Traveller’s Thrombosis. Thorax 2000;55 (Suppl 1):S32-S36.
  [3] Kumar P, Clark M. Clinical Medicine. Fourth Ed. WB Saunders, 1998.