- Inherited (Genetic) Thrombophilias:
- These are caused by mutations in genes that affect blood clotting proteins, making the clotting system overactive or the natural anticoagulant system less effective.
- Factor V Leiden Mutation: The most common inherited thrombophilia, where Factor V is resistant to inactivation by Protein C.
- Prothrombin Gene Mutation (Factor II G20210A): Leads to increased production of prothrombin, a key clotting protein.
- Antithrombin Deficiency: Deficiency of Antithrombin, a natural anticoagulant.
- Protein C Deficiency: Deficiency of Protein C, which inactivates clotting factors.
- Protein S Deficiency: Deficiency of Protein S, which assists Protein C.
- Dysfibrinogenemia: Rare condition where fibrinogen (a clotting protein) is abnormal.
- High Lipoprotein(a) [Lp(a)]: High levels are an inherited risk factor for both atherosclerosis and thrombosis.
- Acquired Thrombophilias:
- These develop due to other medical conditions, medications, or lifestyle factors.
- Antiphospholipid Syndrome (APS): An autoimmune disorder where antibodies (like lupus anticoagulant, anti-cardiolipin, anti-beta2-glycoprotein I) increase clotting risk.
- Cancer: Malignancy often increases the risk of blood clots, especially in certain types of cancer and with specific treatments.
- Myeloproliferative Neoplasms (MPN): Blood cancers like polycythemia vera, essential thrombocythemia, and primary myelofibrosis, which involve overproduction of blood cells.
- Obesity: Increases inflammatory markers and often contributes to other risk factors.
- Surgery or Trauma: Periods of immobility and tissue injury can activate the clotting system.
- Prolonged Immobility: (e.g., long flights, bed rest, casts) Slows blood flow, increasing clot risk.
- Estrogen-Containing Medications: Oral contraceptives, hormone replacement therapy, and selective estrogen receptor modulators (SERMs) increase clotting risk.
- Pregnancy and Postpartum Period: Hormonal changes and physical compression can increase risk.
- Inflammatory Bowel Disease (IBD): Chronic inflammation can increase clotting tendency.
- Nephrotic Syndrome: Kidney disorder leading to protein loss, including natural anticoagulants.
- Paroxysmal Nocturnal Hemoglobinuria (PNH): A rare blood disorder.
- Disseminated Intravascular Coagulation (DIC): A complex disorder causing widespread clotting and bleeding.
- Smoking: Damages blood vessel lining.
- Dehydration.
- Symptoms of Deep Vein Thrombosis (DVT):
- Pain or tenderness in the affected limb (most commonly leg or thigh).
- Swelling (edema) of the affected limb.
- Redness or discoloration of the skin.
- Warmth in the affected area.
- Often, a heavy or aching sensation in the limb.
- Symptoms of Pulmonary Embolism (PE):
- Sudden shortness of breath (dyspnea).
- Chest pain (often sharp, worse with deep breath or cough).
- Rapid heart rate (tachycardia).
- Coughing (may include bloody mucus).
- Dizziness or lightheadedness, fainting.
- Anxiety.
- These are life-threatening symptoms and require immediate medical attention.
- Symptoms of Arterial Clots:
- Stroke: Sudden numbness or weakness (often unilateral), speech difficulty (aphasia/dysarthria), confusion, vision changes.
- Transient Ischemic Attack (TIA - "Mini-stroke"): Temporary stroke-like symptoms that resolve.
- Heart Attack: Chest pain (angina), shortness of breath, pain radiating to arm/jaw, sweating.
- Peripheral Arterial Thrombosis: Pain, numbness, coolness, pallor in a limb.
- Other Less Common Clotting Events:
- Mesenteric Ischemia: Severe abdominal pain due to clots affecting gut blood supply.
- Cerebral Vein Thrombosis: Severe headache, seizures, neurological deficits.
- Recurrent Miscarriages: Due to clots in the placenta (a common symptom in antiphospholipid syndrome).
- Medical History and Physical Exam: The doctor will inquire about personal and family history of blood clots, pregnancy complications, medications, and other medical conditions.
- Blood Tests for Inherited Thrombophilias:
- Factor V Leiden Mutation: Genetic test for the F5 gene mutation.
- Prothrombin Gene Mutation: Genetic test for the F2 gene mutation (G20210A).
- Antithrombin Activity: Measures the level and function of antithrombin.
- Protein C Activity and Antigen: Measures levels and function.
- Protein S Activity and Antigen: Measures levels and function.
- Homocysteine Levels: High levels may indicate a risk (less specific).
- Lipoprotein(a) [Lp(a)] Levels.
- Blood Tests for Acquired Thrombophilias:
- Antiphospholipid Antibodies: Lupus anticoagulant, anti-cardiolipin antibodies (IgG, IgM), anti-beta2-glycoprotein I antibodies (IgG, IgM). (Require repeat testing after 12 weeks for confirmation).
- Tests for Underlying Diseases: Cancer screening, kidney/liver function tests, autoimmune markers, tests for myeloproliferative neoplasms.
- Imaging Tests (if a clot is suspected or present):
- Duplex Ultrasound: For diagnosing DVT.
- CT Pulmonary Angiogram (CTPA): For diagnosing PE.
- CT Scan or MRI: For stroke or other organ clots.
- Anticoagulant Medications (Blood Thinners):
- The cornerstone of treatment for those who have experienced a clot.
- Heparin (Unfractionated or Low Molecular Weight Heparin - LMWH): Used initially for acute clots, given by injection.
- Warfarin (Coumadin): An oral anticoagulant used for long-term prevention. Requires regular INR monitoring.
- Direct Oral Anticoagulants (DOACs): (e.g., rivaroxaban, apixaban, dabigatran, edoxaban) Oral alternatives to warfarin that do not require frequent monitoring. Their use in some specific thrombophilias (e.g., Antiphrombin deficiency, APS) may be limited or require careful consideration.
- The duration of anticoagulation varies from short-term (e.g., 3-6 months for a provoked DVT) to lifelong (for recurrent clots or high-risk thrombophilias).
- Managing Underlying Causes:
- Treating cancer, autoimmune diseases, or myeloproliferative neoplasms.
- Discontinuing or adjusting medications that contribute to hypercoagulability (e.g., estrogen-containing contraceptives).
- Primary Prophylaxis (Prevention in Asymptomatic Individuals):
- Most asymptomatic individuals with an inherited thrombophilia (e.g., heterozygous Factor V Leiden) do *not* require lifelong anticoagulation.
- Prophylactic (preventive) anticoagulation may be given during periods of high risk, such as:
- Major surgery or prolonged hospitalizations.
- Long-duration travel (e.g., flights >4 hours) with additional risk factors.
- Pregnancy and postpartum period (often with LMWH injections for high-risk thrombophilias).
- Low-dose aspirin may be considered for select individuals with high-risk antibody profiles in APS.
- Lifestyle Modifications:
- Quit smoking.
- Maintain a healthy weight.
- Regular physical activity (as advised by a doctor).
- Stay hydrated.
- Avoid prolonged immobility; get up and move frequently.