A blood clot in the leg, or deep vein thrombosis, is a serious condition that can become life-threatening if the blood clot breaks free, travels through the bloodstream and lodges itself in the lungs, explains Mayo Clinic. When this happens, the blood clot blocks blood flow, causing a pulmonary embolism.
Symptoms of pulmonary embolism include shortness of breath with a sudden discomfort or chest pain that becomes more pronounced when coughing or breathing deeply, and coughing up blood, notes Mayo Clinic. Additional symptoms include a rapid pulse, feeling dizzy, lightheadedness or fainting.
Doctors use blood thinners or clot-busting medications to treat deep vein thrombosis, reports Mayo Clinic. Doctors may also insert a filter into a large vein to keep the clot from making its way to the lungs.