Recurrent blood clots

A single blood clot in a vein — a deep vein thrombosis (DVT) in the leg, or a pulmonary embolism (PE) in the lungs — often has a clear provoking cause, such as surgery, a long flight, immobility or pregnancy, and doesn't necessarily mean anything is wrong with the blood. But when clots keep happening — repeated DVTs or PEs, clots without an obvious trigger, or clots at unusual sites — it points more strongly to an underlying reason. The main possibilities are an inherited or acquired clotting tendency (thrombophilia): inherited causes include factor V Leiden and the prothrombin gene mutation, and deficiencies of the natural clotting brakes protein C, protein S and antithrombin; the leading acquired cause is antiphospholipid syndrome, an autoimmune disorder detected through the lupus anticoagulant and related antibodies. Other important drivers of recurrent clotting include an undiagnosed cancer, certain chronic conditions, and ongoing risk factors such as hormonal treatments or immobility. Recurrent clots also raise the question of whether previous treatment was adequate. Because the pattern of recurrence changes how long and how intensively clots are treated, and whether an underlying condition needs addressing, repeated clots are a reason for careful specialist evaluation.

• Inherited thrombophilia — factor V Leiden, the prothrombin mutation, or protein C, protein S or antithrombin deficiency.
• Antiphospholipid syndrome — an acquired autoimmune clotting disorder.
• An undiagnosed cancer — can drive recurrent clotting.
• Ongoing risk factors — the combined pill or HRT, immobility, chronic illness.
• Inadequate or stopped anticoagulation — clots recurring after treatment ends.
• Unusual-site clots — can point to specific conditions.

Recurrent clots usually prompt a thrombophilia work-up and a search for a driver. A doctor may test for factor V Leiden and the prothrombin mutation, protein C, protein S and antithrombin, and the antiphospholipid antibodies (including the lupus anticoagulant) — with attention to timing, because an acute clot and blood thinners distort several of these tests. A D-dimer reflects active clotting. Depending on the picture, investigation for an underlying cancer or other condition may follow. The results guide how long anticoagulation continues and whether an underlying disorder needs treating. Mediora.AI can bring the thrombophilia markers together so the clotting-risk pattern is visible, but the decision to test, how to interpret the results, and how to manage recurrent clots belong with a haematologist.