The typical symptoms of deep venous thrombosis are a swollen extremity, typically of new-onset. Unilateral swelling, especially in the context of recent surgery is the most specific symptom. Sometimes, the extremity is not only swollen, but it might be red and warm. Many times, there are no symptoms, except shortness of breath due to P.E. Leg pain is also not always present. If leg pain and swelling are present in the case of DVT, it does not necessarily correlate with the site of the blood clot. Significant oedema with bluish discolouration of the foot (phlegmasia cerulea dolens) is rare and needs to be treated aggressively.
On physical examination, there is no accurate way of diagnosing deep venous thrombosis. The best way of diagnosing this problem is to suspect it in the clinical situation and perform a Doppler ultrasound test of the extremity. In general, some of the physical examination findings of DVT will include oedema and tenderness. The old standard of Homans sign, which was a pain in the calf muscles with flexing the foot downward does not correlate well with the presence of a DVT. Distension of the superficial veins and superficial phlebitis are sometimes found concomitantly with deep venous clots. Acute thrombosis is also one of the causes of early low-grade fever after surgery.
The diagnosis of deep venous thrombosis is more dependent on clinical suspicion and diagnostic testing than any other factor. Acute shortness of breath, swelling in the limb after surgery, pain in the limb following injury are just some of the signs that might alert the clinician to suspect a deep venous thrombosis. However, Doppler ultrasound is the diagnostic test of choice and should be used liberally if there is a suspicion of deep venous thrombosis. Although not 100% fool-proof, Doppler ultrasound is a non-invasive and simple test to perform to evaluate for a blood clot. Other screening tests are being performed, such as a blood test called a D-dimer test, but none of these other modalities is as reliable as Doppler ultrasound in the hands of a technologist and medical specialist who reviews many studies.
Varicose veins – risk factors
There are many risk factors for deep venous thrombosis, and numerous attempts are made to stratify these risks. The importance of these risks lies in attempts to understand who is at higher risk for a deep vein clot, and when to treat them prophylactically, especially while they are hospitalized to reduce the chance of a DVT. Some of the risks are detailed below.
2. Immobilization longer than 3 days
3. Pregnancy and the postpartum period
4. Major surgery greater than 45 minutes in duration
5. Long plane rides or car trips
7. Previous history of DVT
9. Acute heart attack
10. Congestive heart failure
11. A kidney condition of where one loses large amounts of protein in the urine, called Nephrotic syndrome
12. Ulcerative colitis
13. Major trauma and broken bones
14. Head injury
15. The systemic lupus erythematosus (SLE)
16. Behçet syndrome
18. Polycythemia Rubra Vera (high haemoglobin level)
19. Thrombocytosis (high platelet count, the particles in the blood that clot)
20. Antithrombin III deficiency ( a protein that tries to prevent clotting that occurs in the body)
21. Protein C deficiency ( another protein that tries to prevent clotting that occurs in the body)
22. Protein S deficiency ( another protein that tries to prevent clotting that occurs in the body)
23. Factor V Leiden
24. Prothrombin 20210 mutation
25. Activated protein C resistance
27. Oral contraceptives
28. Heparin-induced thrombocytopenia
28. Other clotting disorders
Once the diagnosis of a deep vein clot is made, then the first treatment choice is to start anticoagulation. The current medication of choice is Lovenox at a dose of 1 mg/kg of body weight, twice daily given as a subcutaneous injection. After Lovenox has been initiated, then an oral blood-thinning agent, Warfarin (Coumadin), is started. Lovenox acts quickly to thin out the blood, while Warfarin takes 3-5 days to reach its full effect. The dose of Warfarin has to be adjusted depending on a blood test called the Protime with INR, or PT with INR. Essentially, the goal level of blood thinning is to achieve an INR of 2.0-2.5. At that time, the Lovenox can be discontinued. Other potential medications that can be used for blood thinning include Heparin, which was the old standard. However, the blood-thinning effects of heparin have to be adjusted based on a blood test, and it is given through the vein or with shots, and therefore is not as convenient as Lovenox.
Recent studies have shown that deep venous thrombosis can be treated safely as an outpatient by initiating Lovenox and Warfarin therapy. Some clinicians still prefer to admit patients to the hospital for initiation of blood thinning, given the potential for PE.
The main point of blood thinning is to prevent enlargement of the blood clot and to stabilize it so that it does not break off and go to the lungs as a PE. The blood clot itself can either dissolve over time, or become chronic clot (scar tissue), or it can reform a channel though the clot where vein blood can flow back towards the heart. Either way, the treatment choice remains blood thinning for 3-6 months. If one has recurrent episodes of DVT, then a year or even lifetime blood thinning with Warfarin might be indicated.