5 Clotting Disorders

How venous thromboembolism occurs

Venous thromboembolism (VTE) includes deep vein thrombosis (DVT), usually in a deep vein of the leg, and pulmonary embolism (PE), which occurs when a clot travels to the lungs. Clotting disorders can increase the risk of harmful blood clots.

Recognizing possible DVT

New swelling, pain or tenderness, warmth, or discoloration in one leg can indicate DVT. Arrange prompt medical evaluation for these symptoms. Do not massage the leg or delay assessment, because a clot can travel to the lungs.

Responding to possible PE

Sudden difficulty breathing or chest pain, especially pain that worsens with a deep breath, may signal PE. Seek emergency medical care immediately rather than reassuring the person that the symptoms are expected, encouraging them to walk, or arranging only a routine follow-up.

Thrombophilia and its causes

Thrombophilia refers to inherited or acquired factors associated with an increased risk of clotting. Examples include factor V Leiden, prothrombin gene mutation, deficiencies of antithrombin, protein C, or protein S, and antiphospholipid syndrome.

When testing may guide care

Thrombophilia testing is not routinely appropriate for everyone after a first clot. It is generally considered selectively when results could affect management. A test result must be interpreted in the person's clinical context; a positive result does not automatically determine treatment duration or mean that lifelong anticoagulation is required. Decisions depend on individual circumstances and the risks of recurrence and bleeding.

What anticoagulants do

Anticoagulants help prevent clots from growing and new clots from forming, but they do not directly dissolve an existing clot. All anticoagulants can cause bleeding, so patients should follow the prescribed plan and promptly report unusual bleeding.

Using anticoagulants safely

Warfarin dosing is monitored with the international normalized ratio (INR). Patients taking warfarin should attend scheduled INR checks, ask their healthcare team before starting a new medicine or supplement, and report unusual bleeding. Medicines and supplements can affect bleeding risk or treatment.

Direct oral anticoagulants (DOACs), including apixaban, rivaroxaban, dabigatran, and edoxaban, are oral medicines used to treat or prevent VTE. Routine INR monitoring is used for warfarin, not as the standard dose-monitoring test for DOACs; suitability and monitoring depend on the medicine and the patient.

Recognizing possible bleeding

Black, tarry stools may indicate bleeding, and feeling faint may signal significant blood loss. These symptoms require urgent medical assessment and prompt notification of the healthcare team. Do not independently change or stop an anticoagulant dose, or add medicines that may increase bleeding risk.

Reducing VTE risk

When clinically appropriate, moving as soon as possible after bed rest, surgery, illness, or injury can help prevent VTE. Depending on the patient's risks and clinical plan, the care team may also consider preventive medication or compression measures.