Deep Venous Thrombosis Deep   venous   thrombosis   often   shortened      DVT   occurs   when   blood clots   in   a   deep   vein   of   the   leg.   It   affects   nearly   2   million   people   in USA   every   year   and   many   die   from   resulting   pulmonary   embolism when the clot breaks off from the leg and moves to the lung. Normally    blood    flows    freely    through    veins.    When    the    flow    is interrupted    either    by    injury    or    by    compression    of    the    vein,    the blood  beyond the point of compression can clot. People at Risk of DVT: • Soon after major surgery involving the hip, knee or leg • After fractures of large bones in the leg • Patients confined to bed after any major surgery • Anyone who is bedridden for prolonged periods • Women on contraceptive Pills • Pregnancy and childbirth • Varicose veins • Airline passengers confined to their seats on long haul flights Generally   the   older   you   are   the   greater   the   chances   of   developing   DVT.   It   is   said   that   the   chances   double   with   each   decade of life after 40. Symptoms: • Swollen leg compared to opposite leg • Leg may be warm and red • Pain in the calf muscle particularly when pressure is applied • Chest pain or difficulty to breathe if the clot moves to the lung Tests for DVT: Clinical examination may suggest a possible DVT. This should be confirmed by one or two tests. • Ultrasound: US will usually confirm a blocked vein from a clot. • D-dimer blood test: If the level of D-Dimer is raised, it is probable that you have DVT. • Venography is sometimes done if the ultra sound is not very clear. • Sometimes MRI or CT scan may be requested. • If pulmonary embolism is suspected a Ventilation/Perfusion scan is done. Preventing  DVT: Steps should always be taken to prevent a DVT rather than worry about it when it happens. In   a   hospital   setting   most   of   the   patients   who   are   subjected   to   major   lower   limb   surgery   will   be   prescribed   blood   thinning medication and maintained on it until they start walking normally. In   many   countries   all   patients   admitted   to   hospital   are   also   given   anti   embolism   stockings   to   wear.   These   are   elastic   stockings that provide uniform compression for the leg preventing pooling of blood in the veins when they are in bed. In     good     operating     theatres     a     pump     will     be     used     on anaesthetised      patients,      to      squeeze      the      calf      muscles intermittently   to   keep   the   blood   circulating   in   the   leg   when   the patient remains still. Older    age    group    people    should    be    encouraged    to    exercise regularly    and    advised    to    avoid    sitting    or    lying    in    bed    for prolonged periods. Long   distance   travelers,   be   it   on   a   plane,   train   or   bus   must   be encouraged    to    exercise    the    leg    muscles    every    hour.    They should   be   advised   if   possible   to   get   out   of   their   seat   and   walk in   the   aisle   from   time   to   time.   If   they   are   unable   to   do   that,   the least   they   can   do   is   move   the   foot   up   and   down   at   regular intervals during the flight. All   these   measures   are   particularly   important   for   individuals   who   have   had   a   DVT   in   the   past   or   have   a   higher   risk   of developing DVT. Treating DVT The main goal of treating a DVT is to stop a clot from increasing in size and stop it getting to the lung. Medication   used   in   DVT      are   collectively   called   anticoagulants.   They   act   by   turning   off   or   delaying   the   clotting   mechanism   in the body. Heparin and Warfarin are the two main drugs used in DVT. Heparin is given by the needle and warfarin as a pill. Once   DVT   is   suspected   and   diagnosed,   treatment   is   started   promptly   with   heparin.   Action   of   Heparin   is   immediate.   Warfarin which   is   also   started   with   heparin   takes   a   longer   time   to   act   (3to   5   days).   Once   warfarin   becomes   effective   heparin   can   be discontinued.   The   time   to   discontinue   heparin   is   determined   by   blood   tests.   While   the   patient   is   on   warfarin   regular   blood tests   will   be   necessary   to   make   sure   that   the   correct   amount   of   warfarin   is   being   given.   Too   much   warfarin   can   cause   internal bleeding.   The   length   of   time   that   a   patient   will   need      warfarin   will   depend   on   the   cause   of   DVT.   It   can   be      anything   between 6 weeks to a year. Anyone   who   suddenly   develops   leg   pain   and   swelling   or   breathing   problems   within   a   week   after   being   in   a   hospital   or   been on a long haul flight should  seek medical advice immediately. K. Badrinath This topic was discussed in greater detail on 4th May in the “Forum” - under “General Topics