Pulmonary edema is a condition caused by excess fluid in the lungs. This fluid collects in the numerous 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, including pneumonia, exposure to certain toxins and 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 requiring immediate care. Pulmonary edema can sometimes cause death. The outlook improves if you get treated quickly. Treatment for pulmonary edema varies depending on the cause but generally includes supplemental oxygen and medications.

Pulmonary edema signs and symptoms may appear suddenly or develop over time. The signs and symptoms you have depends on the type of pulmonary edema.

Sudden (acute) pulmonary edema signs and symptoms

• Difficulty breathing (dyspnea) or extreme shortness of breath that worsens with activity or when lying down
• A feeling of suffocating or drowning that worsens when lying down
• A cough that produces frothy sputum that may be tinged with blood
• Wheezing or gasping for breath
• Cold, clammy skin
• Anxiety, restlessness or a sense of apprehension
• Bluish ips
• A rapid, irregular heartbeat (palpitations)

Long-term (chronic) pulmonary edema signs and symptoms

• Difficulty breathing with activity or when lying flat
• Awakening at night with a cough or breathless feeling that may be relieved by sitting up
• More shortness of breath than normal when you're physically active
• Wheezing
• Rapid weight gain
• Swelling in your lower extremities
• Fatigue
• New or worsening cough

High-altitude pulmonary edema (HAPE) signs and symptoms

HAPE can occur in adults and children who travel to or exercise at high altitudes. Signs and symptoms are similar to those that occur with acute pulmonary edema and can include:

• Headache, which may be the first symptom
• Shortness of breath with activity, which worsens to shortness of breath at rest
• Decreased ability to exercise as you once could
• Dry cough, at first
• Later, a cough that produces frothy, pink sputum
• A very fast heartbeat (tachycardia)
• Weakness
• Chest pain
• Low-grade fever

Signs and symptoms of high-altitude pulmonary edema (HAPE) tend to get worse at night.

When to see a doctor

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 signs and symptoms:

• Shortness of breath, especially if it comes on suddenly
• Trouble breathing or a feeling of suffocating (dyspnea)
• A bubbly, wheezing or gasping sound when you breathe
• Pink, frothy sputum when you cough
• Breathing difficulty along with a lot of sweating
• A blue or gray color to your skin
• Confusion
• A significant drop in blood pressure resulting in lightheadedness, dizziness, weakness or sweating
• A sudden worsening of any of pulmonary edema symptoms

Don't attempt to drive yourself to the hospital. Instead, call 911 or emergency medical care and wait for help.

The causes of pulmonary edema vary. Pulmonary edema is grouped into two categories, depending on where the problem started.

• If a heart problem causes the pulmonary edema, it's called cardiogenic pulmonary edema. Most often, the fluid buildup in the lungs is due to a heart condition.
• If pulmonary edema is not heart related, it's called noncardiogenic pulmonary edema.
• Sometimes, pulmonary edema can be caused by both a heart problem and a non-heart problem.

Understanding the relationship between your lungs and your heart can help explain why pulmonary edema may occur.

How your lungs work

Your lungs contain many small, elastic air sacs called alveoli. With each breath, these air sacs take in oxygen and release carbon dioxide. Normally, this exchange of gases occurs without problems.

But sometimes, the alveoli fill with fluid instead of air, preventing oxygen from being absorbed into your bloodstream.

How your heart works

Your 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 your heart.

Normally, deoxygenated blood from all over your body enters the right atrium then the right ventricle, where it's pumped through large blood vessels (pulmonary arteries) to your 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, flows through the mitral valve into the left ventricle and finally leaves your heart through the largest blood vessel in the body, called the aorta.

The heart valves keep blood flowing in the correct direction. The aortic valve keeps the blood from flowing backward into your heart. From the aorta, the blood travels to the rest of your body.

Heart-related (cardiogenic) pulmonary edema

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 ventricle can't pump out enough of the blood it gets from your 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 your heart muscle can become narrow from fatty deposits (plaques). A slow narrowing of the coronary arteries can make the left ventricle weak. Sometimes, a blood clot forms in one of these narrowed arteries, blocking blood flow and damaging part of your heart muscle, resulting in a heart attack. A damaged heart muscle can no longer pump as well as it should.
• Cardiomyopathy. This term means heart muscle damage. If you have cardiomyopathy, your heart has to pump harder, and pressures go up. The heart may be unable to respond to conditions that require it to work harder, such as exercise, infection or a rise in blood pressure. When the left ventricle can't keep up with the demands that are placed on it, fluid backs up into your lungs.
• Heart valve problems. Narrowing of the aortic or mitral heart valves (stenosis) or a valve that leaks or doesn't close properly affects blood flow into the heart. The heart has to work harder, and pressures go up. If valve leakage develops suddenly, you may develop sudden and severe pulmonary edema.
• High blood pressure (hypertension). Untreated or uncontrolled high blood pressure can enlarge the heart.
• Other heart problems. Inflammation of the heart muscle (myocarditis), congenital heart defects and abnormal heart rhythms (arrhythmias) also may cause pulmonary edema.
• Kidney disease. High blood pressure due to narrowed kidney arteries (renal artery stenosis) or fluid buildup due to kidney disease can cause pulmonary edema.
• Chronic health conditions. Thyroid disease and a buildup of iron (hemochromatosis) or protein (amyloidosis) also may contribute to heart failure and cause pulmonary edema.

Non-heart-related (noncardiogenic) pulmonary edema

Pulmonary edema that is not caused by increased pressures in your heart is called noncardiogenic pulmonary edema.

Causes of noncardiogenic pulmonary edema include:

• Acute respiratory distress syndrome (ARDS). This serious disorder occurs when your lungs suddenly fill with fluid and inflammatory white blood cells. Many conditions can cause ARDS, including severe injury (trauma), widespread infection (sepsis), pneumonia and severe bleeding.
• Adverse drug reaction or drug overdose. Many drugs — ranging from aspirin to illegal drugs such as heroin and cocaine — are known to cause pulmonary edema.
• Blood clot in the lungs (pulmonary embolism). If a blood clot travels from the blood vessels in your legs to your lungs, you can develop pulmonary edema.
• Exposure to certain toxins. Inhaling toxins or breathing in some of your stomach contents when you vomit (aspiration) causes intense irritation of the small airways and alveoli, resulting in fluid buildup.
• High altitudes. Pulmonary edema has been seen in mountain climbers, skiers, hikers and other people who travel to high elevations, usually above 8,000 feet (about 2,400 meters). High-altitude pulmonary edema (HAPE) generally occurs in those who don't first become acclimated to the elevation (which can take from a few days to a week or so). But people who live at high altitudes can get HAPE with no elevation change if they have a respiratory infection.
• Near drowning. Inhaling water causes fluid buildup in the lungs that is reversible with immediate medical care.
• Negative pressure pulmonary edema. Pulmonary edema can develop after a blockage in the upper airway causes negative pressure in the lungs from intense efforts to breathe despite the blockage. With treatment, most people with this type of pulmonary edema recover in about 24 hours.
• Nervous system conditions or procedures. A type of pulmonary edema called neurogenic pulmonary edema can occur after a head injury, seizure or brain surgery.
• Smoke inhalation. Smoke from a fire contains chemicals that damage the membrane between the air sacs and the capillaries, allowing fluid to enter your lungs.
• Transfusion-related lung injury. Blood transfusions may cause fluid overload in the left ventricle, leading to pulmonary edema.
• Viral infections. Pulmonary edema can be caused by viruses such as the hantavirus and dengue virus.

Heart failure and other heart conditions that raise pressure in the heart increase the risk of pulmonary edema. Risk factors for heart failure include:

• Abnormal heart rhythms (arrhythmias)
• Alcohol use
• Congenital heart disease
• Coronary artery disease
• Diabetes
• Heart valve disease
• High blood pressure
• Sleep apnea

However, some nervous system conditions and lung damage due to near drowning, drug use, smoke inhalation, viral infections and blood clots also raise your 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 do not first become acclimated to the elevation (which can take from a few days to a week or so).

Children who have existing pulmonary hypertension and structural heart defects may be more likely to get HAPE.

Complications depend on the underlying cause.

In general, if pulmonary edema continues, the pressure in the pulmonary artery can go up (pulmonary hypertension). Eventually, the heart becomes weak and begins to fail, and pressures in the heart and lungs go up.

Complications can include:

• Breathing difficulty
• Swelling of the legs, feet and abdomen
• Buildup of fluid in the membranes that surround your lungs (pleural effusion)
• Congestion and swelling of the liver

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, you can reduce your risk of many kinds of heart problems by taking steps to control your cholesterol and blood pressure. Follow these tips to keep your heart healthy:

• Eat a healthy diet rich in fresh fruits, vegetables, whole grains, fat-free or low-fat dairy, and a variety of proteins.
• Manage your weight.
• Get regular exercise.
• Don't smoke.
• Limit salt and alcohol.
• Manage stress.

Preventing high-altitude pulmonary edema (HAPE)

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 (Adalat CC, Procardia) to help prevent signs and symptoms of HAPE. To prevent HAPE, start taking the medication at least one day before ascent. Ask your doctor how long you need to take the medication after you've arrived at your high-altitude destination.

Breathing problems require immediate diagnosis and treatment. Your doctor can make a preliminary diagnosis of pulmonary edema based on your signs and symptoms and the results of a physical exam, electrocardiogram and chest X-ray.

Once your condition is more stable, your doctor will ask questions about your medical history, especially whether you have ever had cardiovascular or lung disease.

Tests that may be done to diagnose pulmonary edema or to determine why you developed fluid in your lungs include:

• Chest X-ray. A chest X-ray can confirm the diagnosis of pulmonary edema and exclude other possible causes of your shortness of breath. It's usually the first test done when someone has signs or symptoms of pulmonary edema.
• Chest CT. A computed tomography (CT) scan of the chest may not provide the cause for the pulmonary edema, but can give your doctor indirect clues to help make a diagnosis.
• Pulse oximetry. A sensor is attached to your finger or ear and uses light to determine how much oxygen is in your blood.
• Arterial blood gas test. Blood is taken, usually from an artery in your wrist, and checked for the amount of oxygen and carbon dioxide it contains (arterial blood gas concentrations).
• B-type natriuretic peptide (BNP) blood test. Increased levels of BNP may signal a heart condition.
• Other blood tests. Blood tests to diagnose pulmonary edema and its causes also usually include a complete blood count, metabolic panel to check kidney function and thyroid function test.
• Electrocardiogram (ECG or EKG). This painless test detects and records the timing and strength of your heart's signals using small sensors (electrodes) attached to the skin on your chest and legs. The signals are recorded in the form of waves on graph paper or a monitor. An ECG can show signs of heart wall thickening or previous heart attack. A portable ECG machine such as a Holter monitor may be used to continuously monitor your heartbeat at home.
• Echocardiogram. An echocardiogram creates a moving picture of your heart using sound waves (ultrasound). It can identify areas of poor blood flow, abnormal heart valves and heart muscle that is not working normally. Your doctor can use this test to help diagnose fluid around the heart (pericardial effusion).

• Cardiac catheterization and coronary angiogram. This test may be done if an ECG, echocardiogram or other tests don't show the cause of pulmonary edema, or if you also have chest pain.

  During cardiac catheterization, a doctor inserts a long, thin tube (catheter) in an artery or vein in your groin, neck or arm. X-rays help guide the catheter through the blood vessel to your heart. During a coronary angiogram, dye flows through the catheter, allowing blood vessels to show up more clearly on the X-rays. A coronary angiogram can reveal any blockages and measure the pressure in your heart chambers.

• Ultrasound of the lungs. This painless test uses sound waves to measure blood flow through the lungs. It can quickly reveal signs of fluid buildup and plural effusions. Lung ultrasound has become an accurate tool for diagnosing pulmonary edema.

The first treatment for acute pulmonary edema is supplemental oxygen. You usually receive oxygen through a face mask or nasal cannula — a flexible plastic tube with two openings that deliver oxygen to each nostril. This should ease some of your symptoms.

Your doctor will monitor your oxygen level closely. Sometimes it may be necessary to assist your breathing with a machine such as a mechanical ventilator or one that provides positive airway pressure.

Depending on the severity of your condition and the reason for your pulmonary edema, you may also receive one or more of the following medications:

• Diuretics. Doctors commonly prescribe diuretics, such as furosemide (Lasix), to decrease the pressure caused by excess fluid in your heart and lungs.
• Morphine (MS Contin, Oramorph, others). This narcotic may be taken by mouth or given through an IV to relieve shortness of breath and anxiety. But some doctors believe that the risks of morphine may outweigh the benefits and are more likely to use other drugs.
• Blood pressure drugs. If you have high or low blood pressure when you develop pulmonary edema, you'll be given medications to help manage the condition. Your doctor may also prescribe medications that lower the pressure going into or out of your heart. Examples of such medicines are nitroglycerin (Nitromist, Nitrostat, others) and nitroprusside (Nitropress).
• Inotropes. This type of medication is given through an IV if you are in the hospital with severe heart failure. Inotropes improve heart pumping function and maintain blood pressure.

It is important to diagnosis and treat, if possible, any nervous system problems or causes of heart failure.

Treating high-altitude pulmonary edema (HAPE)

As with other forms of pulmonary edema, oxygen is the usually the first treatment. If supplemental oxygen isn't available, you may use portable hyperbaric chambers, which imitate a descent for several hours until you are able to move to a lower elevation.

Treatments for high-altitude pulmonary edema (HAPE) also include:

• Immediately descending to a lower elevation. If you're climbing or traveling at high altitudes and have mild symptoms of HAPE, descend 1,000 to 3,000 feet (about 300 to 1,000 meters) as quickly as you can, within reason. Depending on the severity of your condition, you may need rescue assistance to get off the mountain.
• Stop exercising and stay warm. Physical activity and cold can make pulmonary edema worse.
• Medication. Some climbers take prescription medications such as acetazolamide or nifedipine (Adalat CC, Procardia) to help treat or prevent symptoms of HAPE. To prevent HAPE, medication is started at least one day before ascent.

Lifestyle changes are an important part of heart health and can help you manage some forms of pulmonary edema.

• Keep blood pressure under control. If you have high blood pressure, take your medications as prescribed and check your blood pressure regularly. Record the results. Ask your doctor for your target blood pressure.
• Manage other medical conditions. Address any underlying medical conditions, such as controlling your glucose levels if you have diabetes.
• Avoid the cause of your condition. If pulmonary edema results from drug use or high altitudes, for example, you'll want to avoid these things to prevent further lung damage.
• Don't smoke. It's always a healthy idea to stop smoking. If you need help quitting, talk to your doctor. He or she can provide tips and, sometimes, medications to help you quit smoking.
• Eat less salt. Salt helps your body retain fluid. In some people with severely damaged left ventricular function, getting too much salt may be enough to trigger congestive heart failure. Your doctor may recommend a low-salt diet. If you need help, a dietitian can show you how to determine the salt content in foods and create a nutritious, good-tasting diet. In general, most people should consume less than 2,300 milligrams a day of salt (sodium). Ask your doctor what level is safe for you.
• Choose a healthy diet. You'll want to eat a plenty of fruits, vegetables and whole grains. Limit saturated fats and trans fats, added sugars, and sodium.
• Manage your weight. Being even slightly overweight increases your risk of cardiovascular disease. On the other hand, even losing small amounts of weight can lower your blood pressure and cholesterol and reduce your risk of diabetes.
• Get regular exercise. Healthy adults should get at least 150 minutes of moderate aerobic activity or 75 minutes of vigorous aerobic activity a week, or a combination of the two. If you're not used to exercise, start out slowly and build up gradually. Be sure to get your doctor's OK before starting an exercise program.

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).

What you can do

• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down if you have had similar symptoms in the past, even if you didn't see a doctor.
• Write down key personal information, including any major stresses or recent life changes.
• Obtain copies of medical records whenever possible. Discharge summaries from the hospital and results from heart tests, as well as summary letters from any previous specialists you've seen can be helpful for your new doctor.
• Make a list of all medications as well as any vitamins or supplements that you're taking.
• Keep written track of your weight, and take that record with you so that your doctor can look for any trends.
• Make a list of the salty foods you eat regularly. Mention if you have eaten more of these recently.
• Ask a family member or friend to come along, if possible. Sometimes it can be difficult to remember all of the information provided to you during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your doctor.

Your time with your doctor is limited, so preparing a list of questions will help you make the most of your time together. List your questions from most important to least important in case time runs out. For pulmonary edema, some basic questions to ask your doctor include:

• What's the most likely cause of the symptoms I'm currently experiencing?
• What kinds of tests do I need? Do these tests require any special preparation?
• What do my chest X-ray and electrocardiogram show?
• What treatments are available, and which do you recommend?
• What types of side effects can I expect from treatment?
• Are there any alternatives to the primary approach that you're suggesting?
• What's my prognosis?
• Are there any dietary or activity restrictions that I need to follow? Would it help to see a dietitian?
• Are there any brochures or other printed material that I can take home with me? What websites do you recommend visiting?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment at any time that you don't understand something.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may reserve time to go over any points you want to spend more time on. Your doctor may ask:

• When did you first begin experiencing symptoms?
• Have your symptoms been continuous?
• Have you eaten more salty foods lately?
• How severe are your symptoms? Have your symptoms affected your work or daily activities?
• Have you been diagnosed with obstructive sleep apnea or do you have any symptoms of obstructive sleep apnea?
• Does anything seem to improve your symptoms?
• What, if anything, appears to make your symptoms worse?
• Do you have any family history of lung or heart disease?
• Have you ever been diagnosed with chronic obstructive pulmonary disease (COPD) or asthma?
• Do you smoke or did you smoke in the past? If so, how many packs a day and when did you quit?
• Do you travel to altitudes higher than 1 mile?