It is elusive and masquerades as other diseases. That is how Associate Professor Lee Lai Heng, Senior Consultant, Department of Haematology, Singapore General Hospital, describes Deep Vein Thrombosis (DVT), the condition commonly associated with longhaul flights and popularly known as Economy Class Syndrome. 

​​Pain, swelling and redness of the legs are some symptoms of DVT. But these symptoms can indicate other illnesses, from simple infections to more serious ones like heart failure and kidney diseases. DVT is also difficult to detect, especially in its mild form. A condition in which a blood clot forms in a major vein, DVT can become serious and even life-threatening if a piece of the clot breaks off and travels to the arteries in the lungs. 

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