Deep Venous Thrombosis (DVT) is a very common condition that is notoriously difficult to diagnose in clinic without the use of objective diagnostic testing, such as ultrasound. In fact, it has been shown that up to 70% of cases diagnosed in clinic without objective testing may be incorrect. However, DVT remains an important condition to diagnose quickly and accurately, as left untreated, a DVT can lead to pulmonary embolism (blood clot blocking a blood vessel in a lung) which may lead to death or permanent damage to venous drainage in the leg. Therefore, a podiatrist’s role in treating DVT is recognising the signs of a possible DVT and making an urgent referral for imaging to confirm or refute this suspicion.
The most common area where a DVT may develop is the calf, where a thrombus may develop in the sinuses of the soleus muscle and the posterial tibial and peroneal veins. The DVT may also form higher up in the leg, in the area of the inguinal region or upper thigh, notably within the femoral and iliofemoral veins. The latter tends to cause the most severe symptoms as the site of blockage is more proximal (further from the extremities).
The following are common symptoms of a DVT:
- Symptoms that start 3-10 days after surgery or after a week or more following a long distance flight.
- Slight pyrexia (fever).
- Mild pain in the calf that is worse when exercising.
- Swelling of the leg distal to the site of the DVT (between the DVT and the toes).
- Distention of the superficial veins.
- Leg may feel warmer distal to the site of the DVT.
- Cyanotic (bluish) colour to the tissues distal to the DVT.
- Pain in the calf when dorsiflexing the ankle (Homan’s sign).
Treatment for DVT involves a combination of physical, pharmacological, and sometimes surgical interventions. Physical measures include bed rest for 1 week with the affected leg elevated. This allows the clot to stabilise. Elastic stockings will be provided to reduce swelling and to protect the superficial veins. The patient will also need to avoid standing for long periods of time for a duration of 3-6 months. Pharmacological treatment involves the use of anticoagulants, such as Warfarin (orally, usually for 3-6 months) and possibly Heparin (intravenously or subcutaneously, for 6-8 days). This reduces new thrombus formation and embolism and prevents thrombus extension. In severe cases, thrombolytic drugs (drugs that break up a clot) will be given, although this comes with a significant risk of haemorrhage. Surgery may be used to fit vena caval filters in cases where people who are unable to take anticoagulants or thrombolytics, who are at risk of pulmonary embolism, or who have already had such an event. These mechanical devices prevent emboli reaching the lungs.