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Pulmonary edema is a condition caused by too much fluid in the lungs. This fluid collects in the many air sacs in the lungs, making it difficult to breathe.
In most cases, heart problems cause pulmonary edema. But fluid can collect in the lungs for other reasons. These include pneumonia, contact with certain toxins, medications, trauma to the chest wall, and traveling to or exercising at high elevations.
Pulmonary edema that develops suddenly (acute pulmonary edema) is a medical emergency that needs immediate care. Pulmonary edema can sometimes cause death. Prompt treatment might help. Treatment for pulmonary edema depends on the cause but generally includes additional oxygen and medications.
Pulmonary edema symptoms may appear suddenly or develop over time. Symptoms depend on the type of pulmonary edema.
HAPE can occur in adults and children who travel to or exercise at high altitudes. Symptoms are similar to those that occur with acute pulmonary edema and can include:
Symptoms of high-altitude pulmonary edema (HAPE) tend to get worse at night.
Pulmonary edema that comes on suddenly (acute pulmonary edema) is life-threatening. Call 911 or emergency medical help if you have any of the following acute symptoms:
Don't drive yourself to the hospital. Instead, call 911 or emergency medical care and wait for help.
The causes of pulmonary edema vary. Pulmonary edema falls into two categories, depending on where the problem starts.
Understanding the relationship between the lungs and the heart can help explain why pulmonary edema may occur.
Lungs contain many small, elastic air sacs called alveoli. With each breath, these air sacs take in oxygen and release carbon dioxide. Typically, this exchange of gases occurs without problems.
But sometimes, the alveoli fill with fluid instead of air. This keeps the bloodstream from taking in oxygen.
The typical heart is made of two upper and two lower chambers. The upper chambers (the right and left atria) receive incoming blood and pump it into the lower chambers (right and left ventricles). The lower chambers pump blood out of the heart.
Typically, blood without oxygen from all over the body enters the right atrium then the right ventricle. From there it's pumped through large blood vessels (pulmonary arteries) to the lungs. There, the blood releases carbon dioxide and picks up oxygen as it flows by the alveoli.
The oxygen-rich blood then returns to the left atrium through the pulmonary veins. It then flows through the mitral valve into the left ventricle. Finally, it leaves the heart through the body's main artery (aorta).
The heart valves keep blood flowing in the right direction. The aortic valve keeps the blood from flowing backward into the heart. From the aorta, the blood travels to the rest of the body.
Cardiogenic pulmonary edema is caused by increased pressures in the heart.
It's usually a result of heart failure. When a diseased or overworked left lower heart chamber (left ventricle) can't pump out enough of the blood it gets from the lungs, pressures in the heart go up. The increased pressure pushes fluid through the blood vessel walls into the air sacs.
Medical conditions that can cause heart failure and lead to pulmonary edema include:
Coronary artery disease. Over time, the arteries that supply blood to the heart muscle can become narrow from fatty deposits (plaques). A slow narrowing of the coronary arteries can weaken the left ventricle.
Sometimes, a blood clot forms in one of these narrowed arteries. The clot blocks blood flow and damages part of the heart muscle, resulting in a heart attack. A damaged heart muscle can no longer pump as well as it should.
Pulmonary edema that is not caused by increased pressures in the heart is called noncardiogenic pulmonary edema.
Causes of noncardiogenic pulmonary edema include:
Heart failure and other heart conditions that raise pressure in the heart increase the risk of pulmonary edema. Risk factors for heart failure include:
Some nervous system conditions and lung damage due to near drowning, drug use, inhaling smoke, viral illnesses and blood clots also raise the risk.
People who travel to high-altitude locations above 8,000 feet (about 2,400 meters) are more likely to develop high-altitude pulmonary edema (HAPE). It usually affects those who don't take the time — a few days to a week or more — to get used to the elevation.
Children who already have pulmonary hypertension and structural heart defects may be more likely to get HAPE.
Complications of pulmonary edema depend on the cause.
In general, if pulmonary edema continues, the pressure in the pulmonary artery can rise (pulmonary hypertension). Eventually, the heart becomes weak and begins to fail, and pressures in the heart and lungs go up.
Pulmonary edema complications may include:
Immediate treatment is necessary for acute pulmonary edema to prevent death.
You may be able to prevent pulmonary edema by managing existing heart or lung conditions and following a healthy lifestyle.
For example, controlling cholesterol and blood pressure can help lower the risk of heart disease. Follow these tips to keep your heart healthy:
To prevent HAPE, gradually ascend to high elevations. Although recommendations vary, most experts advise increasing elevation no more than 1,000 to 1,200 feet (about 300 to 360 meters) a day once you reach 8,200 feet (about 2,500 meters).
Some climbers take prescription medications such as acetazolamide or nifedipine (Procardia) to help prevent symptoms of HAPE. To prevent HAPE, start taking the medication at least one day before ascent. Ask your health care provider how long you need to take the medication after you've arrived at your high-altitude destination.
Breathing problems require immediate diagnosis and treatment. A health care provider can base a diagnosis of pulmonary edema on the symptoms and the results of a physical exam and certain tests.
Once the condition is more stable, the provider can ask about medical history, especially a history of cardiovascular or lung disease.
Tests that can help diagnose pulmonary edema or determine the reason for fluid in the lungs include:
The first treatment for acute pulmonary edema is oxygen. Oxygen flows through a face mask or a flexible plastic tube with two openings (nasal cannula) that deliver oxygen to each nostril. This should ease some symptoms.
A health care provider monitors the oxygen level. Sometimes it may be necessary to assist breathing with a machine such as a mechanical ventilator or one that provides positive airway pressure.
Depending on the severity of the condition and the reason for the pulmonary edema, treatment might include one or more of the following medications:
It is important to diagnosis and treat, if possible, any nervous system problems or causes of heart failure.
Oxygen is the usually the first treatment. If oxygen isn't available, a portable hyperbaric chamber can imitate going down to a lower elevation until it's possible to move to a lower elevation.
Treatments for high-altitude pulmonary edema (HAPE) also include:
Lifestyle changes are an important part of heart health and can help with some forms of pulmonary edema.
If you have pulmonary edema, you will likely first be seen by an emergency room doctor. If you think you have signs or symptoms of pulmonary edema, call 911 or emergency medical help rather than making an outpatient appointment.
You may see several specialists while you're in the hospital. After you are stable, you may be referred to a doctor trained in heart conditions (cardiologist) or lung conditions (pulmonologist).
For pulmonary edema, some questions to ask include:
Don't hesitate to ask other questions.
Your provider is likely to ask you a number of questions, including: