Q: I’ve just read about the risks of deep vein thrombosis for people who spend a lot of time sitting in one place, especially when flying or traveling in general. What should people with ALS know about this and should we be doing anything in particular to prevent it?

Dr. Kasarskis:  That’s a good question. Deep vein thrombosis, or DVT, (also sometimes called venous thromboembolism in its most severe form) is basically the presence of a thrombus or clot within a large blood vessel, usually the veins in the legs. DVT can reduce the blood return from the legs to the heart, but is most significant if detached fragments of the clot travel to the pulmonary arteries in the lungs (termed “pulmonary embolism”, or PE).  In general, we don’t see too many people with ALS with serious complications from deep vein thrombosis. But the immobility or reduced mobility that accompanies ALS puts people with ALS at risk for the problem, even if they’re not traveling.

Symptoms of DVT include swelling, pain and redness in the leg and symptoms of PE can include extreme shortness of breath and chest pain.  PE can be life threatening and requires immediate attention in the ER.  The risk of DVT and PE increases with immobility, for example, on longer trips, although it is still relatively small.

If you’re planning on taking a trip, talk with your physician before you go and ask about whether you should be taking an aspirin daily, or wearing below the knee anti-embolic stockings which compress the legs and help prevent the formation of clots.

And whether you’re traveling or at home, be sure you take in plenty of water and limit alcohol and caffeine to help prevent dehydration. Do simple leg exercises, like flexing your calf muscles against a foot rest while you’re sitting down, to keep your muscles moving, promoting circulation. Even passive exercises when someone else moves and bends your legs and ankles for you can help.  And if you can get up and walk around, whether driving or in a train or a plane, be sure to do so.