Diagnosis

Deep venous thrombosis

Etiology

Cause - Virchows triad [ycs]

1. Stasis: Immobility, venous pressure/mechanical compression: neoplasm, pregnancy, stenosis

2. Hypercoagulable blood:

   • Genetic deficiencies: Anticoagulation proteins C and S, antithrombin III deficiency, factor V Leiden mutation, Polycythaemia rubra vera

   • Acquired: Cancer, sepsis, myocardial infarction, heart failure, vasculitis, systemic lupus erythematosus and lupus anticoagulant, inflammatory bowel disease, nephrotic syndrome, burns, oral estrogens, smoking, hypertension, diabetes, dehydration

3. Vessel injury: Trauma, surgery, venous catheters, previous DVT, IV drug abuse

Pathophysiology [ycs]

1. Virchow triad --> cytokine production --> leukocyte adhesion to the endothelium --> promoting venous thrombosis

2. Thrombosis is a protective mechanism that prevents the loss of blood

3. Fibrinolysis counteracts thrombosis

4. Obstruction of the venous reflux --> erythema, swelling, cyanosis, pain, fever, prominent superficial veins, pain with passive dorsiflexion of the foot (Homan’s sign), venous gangrene, Phlegmasia cerulea dolens (massive swelling, cyanosis, and pain)

5. Remodeling process --> Fibrosis

Anatomic distribution [ycs]

• Leg (the most common area)

• Arms

• Mesenteric veins

• Cerebral veins

Risk factors allowing thrombosis to occur - Virchows triad [ycs]

• Age > 60

• Recent surgery

• Critical care admission

• Fracture/trauma

• Obesity

• Pregnancy

• Dehydration

• Sepsis

• Cancer

• Heart failure

• Myocardial infarction

• Hormone replacement therapy

Complications [ycs]

• Heart attack

• Stroke

• Pulmonary emboli

• Post-thrombotic syndrome

• Death

Epidemiology

Incidence per 100.000 [1q2][vuf][ssg][acp]

Approach

• Blood test:

  • PT-INR

  • Acquired partial thromboplastin time (APTT)

  • Hematocrit

  • Homocysteine

  • Antiphospholipid antibodies

  • Proteins C

  • Protein S

  • Antithrombin III

  • Activated protein C resistance

  • Platelet aggregation

  • Mutant factor V Leiden

  • PT-INR gene mutation

• Ultrasound:

  • Deep venous system

  • Abdomen (evaluate iliac veins and cancer screening if no obvious cause)

• Venography

• CT thorax and abdomen (Pulmonary embolism and cancer screening)

Wells clinical prediction guide

Pretest probability of deep venous thrombosis: high-risk <0p (5%), moderate-risk 1-2p (17%), or low-risk >3p (53%):

• Active cancer +1

• Immobilization of lower extremities +1

• Bedridden >3 days or major surgery <4 weeks prior +1

• Tenderness along the deep venous system +1

• Entire leg swelling +1

• Calf swelling >3 cm compared with asymptomatic leg +1

• Pitting edema +1

• Previous history of DVT +1

• Collateral superficial nonvaricose veins +1

• Alternative diagnosis more likely than DVT -2

Treatment

1. Anticoagulation: first episode --> 3-6 months. Recurrent episodes --> >1 year [2z7]

   • 1st line --> direct oral anticoagulants: dabigatran, rivaroxaban, apixaban

   • 2nd line --> vitamin K antagonist (Warfarin)

   • 3rd line --> Low molecular weight heparin (LMWH)

2. Endovascular mechanical thrombolysis: immediate passage to prevent pulmonary embolism and postthrombotic syndrome

   • Indication:

     • Iliofemoral or IVC thrombosis --> phlegmasia

     • Anticoagulation is contraindicated (intracranial bleeding, recent major surgery (brain/eye/spinal cord), pregnancy, malignant hypertension, severe thrombocytopenia)

     • Pulmonary embolism and systemic shock

     • Inferior vena cava filter is not recommended in patients on anticoagulant therapy

   • Catheter-directed thrombolysis

   • Mechanical thrombectomy

   • Angioplasty

   • Stenting of venous obstructions

3. Surgery:

   • Surgical Thrombectomy: phlegmasia cerulea dolens (massive swelling)

   • Valvuloplasty of chronic venous insufficiency

Differential diagnoses

Acute extremity ischemia, Arthritis, Bakers cyst, Cellulitis, Chronic venous insufficiency, Erysipelas, Heart failure, Lymphedema, Muscle tear, Necrotizing fasciitis, Nephrotic syndrome, Peripheral neuropathy, Postphlebitic syndrome, Pulmonary embolism, Superficial venous thrombosis, Thrombophlebitis, Varices