On this page we explain what a pulmonary embolism is, what the common symptoms are and when you should seek medical help.
What is a pulmonary embolism?
A pulmonary embolism happens when a blood vessel in your lungs becomes blocked. Most of the time, this blockage is caused by a blood clot and happens suddenly.
It can be very serious because it can stop blood going to your lungs. Fast medical treatment can be lifesaving.
Call 999 if:
- you have severe breathing difficulty or
- your heart is beating very fast or
- someone has passed out
These could be signs of a pulmonary embolism or another serious condition.
What’s the difference between acute and chronic pulmonary embolism?
An acute pulmonary embolism is when there’s a sudden blockage in the blood vessel in the lungs. Our information is focused on acute pulmonary embolism.
A chronic pulmonary embolism is when the blood vessels in the lungs have been blocked for a longer period of time. Most commonly it occurs because previous blood clots haven’t dissolved completely after an acute pulmonary embolism. A significant amount of clot remains in approximately 2% of patients (1 in 50) following an acute pulmonary embolism, leading to increased pressure within the lungs. This condition is called chronic thromboembolic pulmonary hypertension (CTEPH).
What are the symptoms of a pulmonary embolism?
The symptoms of a pulmonary embolism vary between different people and how large the clot is. Sometimes a small pulmonary embolism may cause no symptoms at all. The symptoms of a blood clot to the lungs are also seen in other lung conditions.
The main symptoms of a pulmonary embolism are:
- chest pain
- feeling short of breath
- difficulty breathing
- coughing up blood
- feeling faint or even passing out.
Most pulmonary embolisms are caused by deep vein thrombosis (when a blood clot develops in a deep vein in the body, usually in the leg). So, another warning sign can be a painful, red or swollen leg (usually the calf). You can read more about what DVT looks like on the NHS website.
See a GP if:
- you feel pain in your chest or upper back
- you have difficulty breathing
- you’re coughing up blood
- you have pain, redness and swelling in one of your legs (usually the calf)