DVT is a  is a condition in which a blood clot is embedded in one of the major deep veins of the lower legs, thighs, pelvis, or arm. A clot blocks blood circulation through these veins, which carry blood from the lower body back to the heart. The blockage can cause acute pain, swelling, or warmth in the affected leg. DVT is a medical emergency.




Typically, patients will experience sudden and increasing pain and swelling in their leg ( commonly back of the calf and behind the knee) and  redness of the skin and swelling of  the leg. Some patients may also find the leg is increasingly tender to the touch.

If you have any of these symptoms you should seek medical attention immediately as there is a chance that this clot may dislodge or the clot breaks loose (or embolizes) and travels through the bloodstream, causing blockage of blood vessels (pulmonary arteries) in the lung. This condition is called pulmonary embolism (PE), and can lead to severe difficulty in breathing and even death, depending on the degree of obstruction of the blood vessel. Patients with PE complain of sudden onset of severe chest pains, cough and shortness of breath.

But not all patients will have these classic signs of DVT. Did you know that up to 50% of patients have no symptoms ? This is why it is imperative to get your legs checked by a medical doctor as soon as possible.  

Symptoms and signs of DVT include:

  • Swelling
  • Pain
  • Redness
  • Warmth to the touch
  • Worsening leg pain when bending the foot
  • Leg cramps, throbbing sensation(especially at night and/or in the calf)
  • Discoloration of skin


DVT is can be caused by 1 of 3 mechanisms: reduction in the normal blood flow rate in the veins of the legs, injury or trauma to the lining of the blood vessel (vein) or certain conditions in which the blood is more viscous than usual and has a natural tendency to clot easily ( hypercoagulable states).


  • Prolonged sitting or immobility – including long plane flights, long car rides, even jobs that require long periods of sitting.
  • Recent surgery – particularly orthopedic (especially hip, leg, or , knee such as knee or hip replacement), gynecologic, heart, or abdominal surgery
  • Recent trauma to the lower body including fractures to the bones of the hip,thigh, leg or knee.
  • Prolonged bed rest or immobility, such as after injury or during illness (for example stroke)
  • Obesity 
  • Heart attack or heart failure
  • Pregnancy or recent childbirth
  • High altitudes (greater than 14,000 feet)
  • Estrogen therapy or birth control pills (hypercoagulable state)
  • Cancer (hypercoagulable state)
  • Medical conditions that affect the veins such as vasculitis (inflammation of the vein walls), varicose veins
  • Superficial venous thrombosis (SVT) occurs when a blood clot forms in a superficial vein near the surface of the body. While not the same as DVT (which occurs in deep veins) it can be a risk factor for DVT/PE
  • Rare genetic conditions that affect blood clotting factors ( hypercoagulable state)
  • Certain heart or respiratory conditions
  • Advanced age
  • Medical conditions that affect the veins

If an individual has one deep vein thrombosis, they are 33% more likely to develop a second deep vein thrombosis within 10 years.


If you suspect you may have DVT, immediately go to your family physician for a physical examination and assessment. Your doctor will order a Venous Doppler Ultrasound examination. We highly recommend you get scanned by a qualified Radiologist ( a medical doctor who specializes in medical imaging). 

The Venous Doppler ultrasound is a fast, safe (no radiation), non-invasive method of evaluating the veins in the legs as well as examine the blood flow in your veins in real-time. Your Radiologist will be looking for specific signs of DVT including veins that are non-compressible as well as the identification of the actual clot within the blood vessel, its size, extent of obstruction, and location.

  Ultrasound images of a normal and a thrombosed vein

Not only can the actual clot be visualized with ultrasound, but the blood flow can be assessed to determine the extent of obstruction. Color Doppler assists in this part of the examination.

Doppler ultrasound image of a major vein completely blocked by a clot – positive DVT

The artery “lights up” (orange-red) as blood flows through it freely as opposed to the vein which shows absolutely no blood flow due to complete obstruction.

Once found to be positive, your Radiologist will send you to the nearest tertiary healthcare facility / hospital, as this is considered a medical emergency. Treatment of DVT in the leg is individualized for each patient. Usually, anticoagulation or blood-thinning medication is prescribed to prevent further clot formation and to minimize the risk that part of the blood clot will break off and travel to the lung and cause pulmonary embolism. Some patients may have a further test performed in the hospital to exclude possible PE. This test is called a CT Pulmonary angiogram (CTPA). This test  will require you to get an injection of iodinated contrast and before this is done, your kidneys must be tested to ensure they are functioning normally. If you have any allergies to shellfish or if you had a previous adverse reaction to iodinated contrast, please inform your doctor so that you can receive the right pre-medication before the CT examination. 


The key to prevention of DVT is to reverse any risk factors, for example:

  • Lose weight if overweight or obese- maintain a healthy weight
  • Avoid periods of prolonged immobility. Get up and move around every 15 to 30 minutes during long plane flights. Do simple stretching exercises while seated. Make frequent stops and get out of the car when driving long distances.
  • Exercise regularly 
  • Avoid crossing your legs while seated,
  • Elevate your legs when resting, and
  • Avoid wearing tight-fitting clothing around your waist, groin and legs.
  • Keep the legs elevated while sitting down or in bed.
  • Avoid high-dose estrogen pills, unless they are deemed necessary by the doctor.

In the case of recent surgery, preventive treatment may be prescribed to avoid formation of a clot.

  • The patient may be instructed to get out of bed several times a day during the recovery period.
  • Sequential compression devices (SCDs) may be placed on the legs. Their squeezing action has been shown to reduce the probability of clot formation. The patient may also be given elastic compression socks or stockings to wear.
  • Low-molecular-weight heparin or low-dose warfarin may be prescribed to prevent clot formation.

Don’t ignore your pain……

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