Deep Venous Thrombosis

This essay concerns the diagnosis of deep venous thrombosis (DVT). The intent is to decrease the unnecessary use of diagnostic testing for possible DVT without increasing the miss rate.  DVT is a serious, relatively common, and often treatable disease. As such, identifying patients with DVT is important. Anticoagulant treatment is known to decrease the risk of symptomatic pulmonary embolism in the setting of DVT. The effect on post-phlebitic syndrome is less clear.

  Who should be tested for DVT?
Unilateral swelling of an extremity should lead to consideration of DVT. Diffuse (though mild) pain is also usually noted. The H+PE often reveals another cause, negating the need for more testing. These causes include the following.

Bilateral lower extremity edema
Bilateral lower extremity edema (BLLEE) is not a common presentation of DVT, even though DVT is also found fairly commonly in the asymptomatic leg when DVT is diagnosed in a symptomatic leg. When another cause of bilateral edema (heart failure, hypo-albuminemia, etc.) is present it is not necessary to further consider DVT.

 Pain without edema
Pain may precede edema in DVT.

 How to test for DVT
The two basic choices are D-dimer testing and Doppler ultrasound. Evidence based medicine is extremely useful in helping to decide which test is indicated.

 Is immediate Doppler testing indicated when DVT is suspected?
No. As noted above, Doppler testing is often not available 24/7. Even when it is available, during non-working hours an on-call technician must often be called in. This is expensive and time consuming.

What about upper extremity DVT?
Most upper extremity DVT (UE DVT) is associated with intravascular devices such as PICC lines, other central venous catheters, pacemaker placement, etc.

The above picture is a right leg DVT. Notice the plethoric, diffusely swollen apperance. The next picture is of cellulitis. Notice that it is bright red with definite borders and is swollen only where it's red.