Thrombophilia is a condition where the blood has an increased tendency to form clots. A blood clot within a vein is known as a venous thrombus and the most common form is deep vein thrombosis (DVT), which is a blood clot in a deep vein, predominantly of the leg. If this blood clot breaks loose and travels to the lungs, it is known as a pulmonary embolus and can be very dangerous. A less common (and more severe) form of venous thrombus is known as cerebral venous sinus thrombosis, where a blood clot forms in the dural venous sinuses, which drain blood from the brain.
The symptoms of DVT can include swelling and warmth, pain or tenderness and a color change (increased redness). However, these symptoms are not always present so diagnosis can be difficult.
The symptoms of a pulmonary embolus include a shortness of breath, chest pain, coughing up blood, an increased heart rate, lightheadedness and rapid breathing.