A severe thrombosis means a blood clot that can block normal blood flow. Symptoms depend on where the clot forms. Some clots are life-threatening and need urgent medical attention.
Possible warning signs of a dangerous clot
1. Deep vein thrombosis (DVT — usually in the leg)
- Swelling in one leg (especially sudden)
- Pain, tenderness, or cramping in the calf or thigh
- Warmth over the affected area
- Red or discolored skin
2. Pulmonary embolism (clot that travels to the lungs — emergency)
- Sudden shortness of breath
- Chest pain (especially sharp pain that worsens with breathing)
- Rapid heartbeat
- Coughing, sometimes with blood
- Feeling faint or collapsing
3. Stroke caused by a clot
- Sudden weakness or numbness on one side of the body
- Facial drooping
- Trouble speaking or understanding speech
- Sudden vision problems
- Loss of balance or coordination
4. Heart attack caused by a blocked artery
- Pressure, squeezing, or pain in the chest
- Pain spreading to the arm, jaw, back, or shoulder
- Sweating, nausea, or shortness of breath
Seek emergency help immediately if there is:
- Sudden breathing difficulty
- Chest pain with shortness of breath
- Stroke-like symptoms (face drooping, arm weakness, speech trouble)
- Fainting or severe sudden weakness
Risk factors for blood clots include prolonged immobility, recent surgery, certain cancers, pregnancy/postpartum changes, smoking, some hormone medications, obesity, and previous clotting problems.
If you’re asking because of a specific symptom you or someone else is experiencing, tell me the symptom, when it started, and where it is occurring.
