Pulmonary oedema is an excess of watery fluid in the lungs.
People with sudden onset of pulmonary oedema usually need urgent admission to hospital. Treatment includes oxygen, medicines to remove the excess fluid from the lungs (diuretics), and other medicines to help the heart work more effectively.
Further treatment will depend on the cause of the pulmonary oedema. Pulmonary oedema may be life-threatening, especially without urgent medical treatment.
What is pulmonary oedema?
What is high altitude pulmonary oedema?
High altitude pulmonary oedema (HAPE) is a type of pulmonary oedema that occurs in previously healthy people who go to high altitude regions (for example climbing mountains). It is a severe form of altitude sickness. It usually happens when a person who lives at low altitude travels to an altitude above 2500 metres. It is not caused by a problem with the heart.
What is swimming-induced pulmonary oedema?
Swimming-induced pulmonary oedema (SIPE) is also known as immersion pulmonary oedema. It occurs when you exercise whilst in water, for example swimming and scuba-diving. The frequency has increased with the recent popularity of triathlons and open-water swimming events.
What is the difference between pulmonary oedema and pneumonia?
Pulmonary oedema and pneumonia may have similar symptoms. However they have different causes. Pulmonary oedema is an excess of watery fluid building up in the lungs, usually caused by a heart problem. Pneumonia is an infection of the lungs, which could be caused by a bacteria, virus or fungus. Pneumonia can cause pulmonary oedema because the infection of the lung tissue can cause fluid to build up.
What is the difference between pulmonary oedema and pleural effusion?
Pulmonary oedema is the collection of excess fluid in the tissues and air sacs in the lungs. A pleural effusion is a collection of fluid in the lining on the outside of the lungs.
Symptoms of pulmonary oedema
Symptoms may include:
- Shortness of breath.
- Breathlessness when exercising.
- Difficulty breathing when lying down flat (orthopnea). You may need to sleep with your head propped up with extra pillows.
- Waking in the night feeling breathless.
- Coughing up blood or bloody froth (haemoptysis).
Other symptoms may include anxiety or restlessness, a reduced level of consciousness and excessive sweating. You may have a blue tinge colour of your lips or fingers.
Causes of pulmonary oedema
Pulmonary oedema can occur because of the following reasons:
- Heart failure (cardiogenic pulmonary oedema).
- An increase in pressure in the blood vessels in the lungs. This often occurs with heart failure, where the heart is pumping blood less efficiently.
- Damage to the very small blood vessels (capillaries) in the lungs, allowing more fluid to pass into the lungs. This occurs with lung injury - eg, smoke inhalation or pneumonia.
- Failure of the vessels (lymphatics) to clear fluid from the lungs.
Cardiogenic pulmonary oedema
Pulmonary oedema is most often caused by heart failure. Heart failure that leads to pulmonary oedema may be due to a number of different causes. These may include:
- A heart attack.
- Any disease of the heart that weakens or stiffens the heart muscle (hypertrophic cardiomyopathy or dilated cardiomyopathy).
- Leaking or narrowed heart valves (mitral or aortic valves).
- An abnormal rhythm.
- Sudden, severe high blood pressure (hypertension).
When the heart is not able to pump blood to the body efficiently, the amount of blood staying in the veins that take blood through the lungs to the left side of the heart increases.
As the pressure in these blood vessels increases, fluid is pushed into the air spaces (alveoli) in the lungs. This fluid reduces normal oxygen movement through the lungs, which can lead to shortness of breath.
Non-cardiogenic pulmonary oedema
Pulmonary oedema may also be caused by conditions other than heart conditions, including:
- High-altitude exposure.
- Acute (adult) respiratory distress syndrome (ARDS).
- Acute kidney injury or chronic kidney disease.
- Lung damage caused by poisonous gas or severe infection.
- Pulmonary embolism.
- Following a major injury.
When to see a doctor
If you think you have any of the symptoms of pulmonary oedema that are described above you should see a doctor. If the symptoms come on gradually you should see your GP. If you have sudden or very severe symptoms (especially breathlessness) then you should call an ambulance or go to the nearest A&E department.
How is pulmonary oedema diagnosed?
An examination by a doctor will include:
- Checking the rate and rhythm of your heartbeat (pulse).
- Checking your blood pressure.
- Checking how fast you are breathing.
- Listening with a stethoscope for abnormal noises in the lungs, indicating that abnormal fluid is present.
- Listening for heart murmurs, indicating a problem with the heart valves.
- Blood tests, which are carried out to look for:
- Kidney function.
- Levels of salts in the blood.
- Whether pulmonary oedema has been caused by a heart attack.
- A substance called natriuretic peptide, which tends to be raised in people with heart failure.
- Monitoring blood oxygen levels, using pulse oximetry, which uses a sensor placed over a thin area of skin such as a fingertip.
- Chest X-ray to look for signs of heart failure or any other problem in the lungs, such as pneumonia.
- An ultrasound scan of the heart (an echocardiogram) to see if there are problems with the heart muscle (such as weakness, thickness, failure to relax properly, leaky or narrow heart valves, or fluid surrounding the heart).
- A 'heart tracing' (electrocardiogram, or ECG) to look for signs of a heart attack or problems with the heart rhythm.
How is pulmonary oedema treated?
People with sudden onset of pulmonary oedema usually need urgent admission to hospital. They require treatment with:
- Oxygen (if body oxygen levels are low).
- Medicines to remove the excess fluid from the lungs (diuretics).
- Other medicines to help the heart work more effectively.
These medicines are usually given through the veins (intravenously, or IV). Further treatment will depend on the cause of the pulmonary oedema. See also the separate leaflet called Congestive Heart Failure.
Urgent treatment is also needed for the cause of the pulmonary oedema, such as treatment for a heart attack, high-altitude sickness or acute kidney injury.
If oxygen and medicines do not successfully treat the pulmonary oedema, it may be necessary to use a ventilator or other methods to help with breathing until the pulmonary oedema is improving.
Are there any complications?
If pulmonary oedema continues, it can cause increased pressure in the right side of the heart and eventually cause the right ventricle to fail. Failure of the right ventricle can cause fluid swelling of the legs (oedema), fluid swelling of the tummy (abdomen), called ascites, and congestion and swelling of the liver.
Preventing pulmonary oedema
Pulmonary oedema can only be prevented by preventing the causes of the oedema. The most common cause is heart problems. You can help to keep your heart healthy by:
- Not smoking.
- Drinking no more than the recommended amounts of alcohol (14 units per week for women and 21 units per week for men).
- Eating a balanced, healthy diet.
- Taking regular, physical exercise.
- Keeping to a healthy weight.
- Keeping your blood pressure under control.
- Keeping diabetes under control if you have it.
- Taking any medication you are prescribed, especially if you have a heart condition.
- If you are going to a high altitude region, take expert advice before you travel.
The outlook (prognosis) depends on the cause of the pulmonary oedema. Pulmonary oedema may get better, either quickly or slowly. However, it can also be life-threatening, especially without urgent medical treatment.
Further reading and references
Diagnosing and managing acute heart failure in adults; NICE Clinical Guidelines (Oct 2014 - updated Nov 2021)
Purvey M, Allen G; Managing acute pulmonary oedema. Aust Prescr. 2017 Apr40(2):59-63. doi: 10.18773/austprescr.2017.012. Epub 2017 Apr 3.
Chronic heart failure in adults - diagnosis and management; NICE Guidance (Sept 2018)
2021 ESC Guidelines for the diagnosis and treatment of acute and chronic heart failure; Developed by the Task Force for the diagnosis and treatment of acute and chronic heart failure of the European Society of Cardiology (ESC) With the special contribution of the Heart Failure Association (HFA) of the ESC