Deep vein thrombosis

Introduction

Deep vein thrombosis (DVT), or phlebitis, refers to the formation of a blood clot in a deep vein, most commonly in the lower limbs. It is a common condition affecting about 1 in 1,000 people per year, but above all, a potentially serious condition: an untreated clot can break off and migrate to the lungs, causing a pulmonary embolism, which is a life-threatening emergency. Diagnosis is sometimes difficult because symptoms are not very specific. Prompt management is essential.

If your leg is painful, swollen, or red, contact your primary care physician first. If they are unavailable, Docadom offers an emergency consultation by a doctor at home: call 021 845 45 45 or use our application available on the App Store and Google Play.

Who is at risk?

Risk factors are numerous and well-identified. They correspond to Virchow's triad: venous stasis, hypercoagulability, and vessel wall injury.

• Prolonged immobilization: bed rest, cast, long travel (> 6 hours), hospitalization, post-surgery.

• Surgery, particularly orthopedic (hip, knee), abdominal, or pelvic.

• Active cancer and chemotherapy.

• Pregnancy and postpartum.

• Estrogen-progestogen contraception, hormone replacement therapy.

• Hereditary thrombophilias (Factor V Leiden, prothrombin mutation, deficiencies in antithrombin, protein C, protein S).

• Advanced age, obesity, smoking.

• Personal or family history of DVT or pulmonary embolism.

• Heart failure, chronic inflammatory diseases, nephrotic syndrome, COVID-19.

Symptoms of Deep Vein Thrombosis

Symptoms are often non-specific or even absent. Suspicion must always be confirmed by additional diagnostic testing.

Main Symptoms

• Pain in the calf or thigh, spontaneous or on palpation.

• Asymmetrical edema: swelling of one leg compared to the other, pitting.

• Redness and local warmth.

• Tension or hardness of the calf.

• Dilation of superficial veins.

• Homans' sign: pain on dorsiflexion of the foot (neither sensitive nor specific).

• Sometimes mild fever (38 °C / 100.4 °F).

• Possible symptoms of associated pulmonary embolism: dyspnea, chest pain, tachycardia, syncope.

When to Seek Emergency Consultation?

An emergency consultation is necessary in the following situations:

• Painful, swollen, red, or warm leg, especially in the presence of risk factors.

• Sudden onset of dyspnea, chest pain, or tachycardia (suspected pulmonary embolism) — call 144 immediately.

• DVT in a pregnant woman, postpartum, or in a patient on high-risk treatment.

• Recurrent DVT or DVT in a young individual (investigation for thrombophilia).

• Phlegmasia cerulea dolens (very extensive DVT with limb ischemia): blue, cold, extremely painful leg — absolute emergency.

What to do before calling Docadom? Do not massage the leg (risk of dislodging the clot), contact your primary care physician first. If they cannot be reached or if you need a house-call doctor outside opening hours, call Docadom at 021 845 45 45 or make your request directly from our smartphone app (App Store and Google Play). In case of signs of pulmonary embolism (sudden shortness of breath, chest pain, syncope), dial 144 without delay.

Causes and Mechanisms

DVT results from the formation of a thrombus in the deep venous system, promoted by the three elements of Virchow's triad: venous stasis (slow blood flow), hypercoagulability (excess clotting), and vessel wall injury.

Transient Factors

Major orthopedic surgery, trauma, immobilization, prolonged travel, pregnancy, postpartum, estrogen-progestogen contraception, COVID-19, severe infections.

Persistent Factors

Active cancer, hereditary or acquired thrombophilia, chronic inflammatory disease, heart failure, history of thromboembolism, age > 70, obesity.

Diagnosis of Deep Vein Thrombosis

Diagnosis is based on the assessment of clinical probability, D-dimers, and venous ultrasonography.

Diagnostic Methods

• Anamnesis and clinical examination: investigation of risk factors, measurement of calf circumference.

• Wells Clinical Score: allows stratification of probability (low, intermediate, high).

• D-dimers: if clinical probability is low or intermediate and D-dimers are normal, DVT is ruled out. If elevated, imaging is required.

• Venous Duplex Ultrasound of lower limbs: the reference test. Visualizes the clot and its extension.

• Venography: exceptionally used.

• In case of signs suggesting pulmonary embolism: emergency CT pulmonary angiogram (CTPA).

• Screening for occult cancer or thrombophilia depending on the context.

Alternative Diagnostics

• Cellulitis or erysipelas.

• Calf hematoma.

• Ruptured Baker's cyst.

• Muscle strain or tendinitis.

• Chronic venous insufficiency, lymphedema.

• Heart failure with bilateral edema.

• Lymphangitis.

Treatment of Deep Vein Thrombosis

Anticoagulation

Treatment relies on anticoagulation, which prevents the clot from expanding and avoids pulmonary embolism:

• Initial phase: low molecular weight heparin (enoxaparin, tinzaparin), fondaparinux, or directly a direct oral anticoagulant (DOAC) — rivaroxaban, apixaban.

• Maintenance phase: DOAC (rivaroxaban, apixaban, dabigatran, edoxaban) or VKA (warfarin) with target INR 2-3.

• Duration: at least 3 months, extended in case of persistent risk factors, cancer, or recurrence.

• In pregnant women: low molecular weight heparins only.

Associated Measures

• Early mobilization once effective anticoagulation is established.

• Class II or III compression stockings for several months, to reduce the risk of post-thrombotic syndrome.

• Analgesics for pain relief.

• Search for and treat the underlying cause (occult cancer, thrombophilia).

• Patient education: signs of pulmonary embolism, bleeding signs, drug interactions.

Specific Treatments

• Thrombolysis or thrombectomy: exceptionally, in very extensive DVT (phlegmasia cerulea dolens) or with ischemia.

• Vena cava filter: in case of contraindication to anticoagulation or recurrence despite well-conducted treatment.

Prevention of Deep Vein Thrombosis

• Early mobilization after surgery or childbirth.

• Preventive anticoagulation with LMWH during high-risk surgery, prolonged bed rest, or in oncology.

• Compression stockings for patients at moderate risk or during long travels.

• Abundant hydration during long journeys.

• Leg mobilization during prolonged trips.

• Regular physical activity, smoking cessation, maintaining a healthy weight.

• Assessing the benefit/risk ratio of hormone therapies.

• Close follow-up of patients with a history of thromboembolic events.

• Recommended vaccinations (influenza, COVID-19).

Possible Complications

The most serious complication is a pulmonary embolism, which is a medical emergency. Other complications include: recurrence of DVT, post-thrombotic syndrome of the lower limbs (pain, swelling, heaviness, venous ulcers) — common and disabling, chronic thromboembolic pulmonary hypertension (rare but severe), bleeding complications related to anticoagulant treatment, and psychological impact (anxiety, fear of recurrence).

When to Contact a Doctor for Suspected DVT

Any painful, swollen, or red leg deserves prompt medical evaluation:

• First line of care: contact your primary care physician, who can evaluate the clinical probability and prescribe an emergency Duplex ultrasound.

• If your primary care physician is unavailable (evenings, weekends, holidays), Docadom offers an emergency consultation by a doctor at home. Call 021 845 45 45 or make your request via our mobile application, available for free on the App Store and Google Play.

• In case of signs of pulmonary embolism (sudden dyspnea, chest pain, syncope, marked tachycardia), call 144 without delay.

Conclusion: Early Suspicion and Confirmation

Deep vein thrombosis is a common, potentially serious condition. It is characterized by unilateral pain, edema, and redness of a leg, which can lead to major complications such as pulmonary embolism, post-thrombotic syndrome, or chronic pulmonary hypertension. Diagnosis is based on the Wells score, D-dimers, and venous Duplex ultrasound. When initiated promptly, anticoagulant therapy prevents major complications and saves the patient's life.

If you suspect a leg issue, consult your primary care physician first. If they are not available, Docadom provides an emergency home doctor 7 days a week: call 021 845 45 45 or use our mobile application (App Store, Google Play) to request an emergency consultation.