Pulmonary edema is usually accompanied by significant breathing problems and can easily lead to a life-threatening emergency. Read more about early warning signs, symptoms, causes and treatment, and what to do in an emergency. With pulmonary edema, fluid collects in the lungs. Doctors speak of pulmonary edema. Colloquially, pulmonary edema is also referred to as water in the lungs. Strictly speaking, these are liquid components of the blood that are pressed into the lung tissue from the finest blood vessels in the lungs, the lung capillaries. The function of the lungs is restricted by the free fluid.
In pulmonary edema, depending on the localization of the fluid, a distinction is made between two forms that can quickly merge without therapy:
- Interstitial pulmonary edema: fluid accumulation in the connective tissue support structure or in the tissue between the cells, the interstitium
- Intraalveolar pulmonary edema: accumulation of fluid within the finest alveoli.
Pulmonary congestion is a less pronounced preliminary stage of pulmonary edema. Especially in people with left heart failure and kidney failure, pulmonary congestion occurs as a chronic form of pulmonary edema.
Pulmonary edema usually causes clearly noticeable symptoms such as accelerated shallow breathing, rattling breath sounds, coughing, and shortness of breath. If left untreated, pulmonary edema can be life-threatening. If you have symptoms, you should seek medical help immediately. If the symptoms are severe, the emergency doctor should be called.
The most common causes of pulmonary edema are heart disease (cardiac pulmonary edema). Other causes include kidney disease (renal pulmonary edema), poisoning (toxic pulmonary edema), or a lack of oxygen at high altitudes (high altitude pulmonary edema). Sunstroke (cerebral pulmonary edema) can also lead to pulmonary edema under unfavorable circumstances. See the Causes section below for details.
With timely medical help, the life-threatening acute symptoms of pulmonary edema can in most cases be managed well with oxygen treatment and drug therapy. The long-term healing prospects depend primarily on whether the triggering circumstances can be eliminated.
The exact frequency of pulmonary edema is not recorded. From medical practice, however, it can be said that it is a common complication of heart diseases, for example, especially heart failure. The prevalence (incidence) of heart failure is given in the literature to be up to 2 percent. The frequency increases sharply from the age of 60.
According to the German Heart Foundation, up to 3 million men and women in Germany are affected by heart failure. Around 450,000 people are hospitalized for cardiac insufficiency each year. Almost 10 percent do not survive.
The symptoms of pulmonary edema differ according to four degrees of severity.
Stage I: interstitial pulmonary edema
Doctors refer to stage I as interstitial pulmonary edema. Interstitial means that the fluid collects in the connective tissue of the lungs or between the cells of the lung tissue. At this stage, pulmonary edema is mainly noticeable as breathing difficulties. Most of the time, breathing is much faster and shallower. Typically, these symptoms of pulmonary edema subside when the person concerned is elevated or standing. Further symptoms of interstitial pulmonary edema are cough and a noticeable restlessness.
Stage II: Alveolar pulmonary edema
In stage II, the fluid from the lung tissue first penetrates into the alveoli. This is why doctors speak of alveolar pulmonary edema. Later, the fluid also collects in the small bronchi (bronchioles). Typical symptoms of this pulmonary edema stage are increasing shortness of breath and intensifying cough, which is sometimes accompanied by whitish-foamy sputum. Breathing sounds can be heard (so-called wheezing), the pulse is racing (tachycardia), the patients are pale and are afraid of suffocating. At the latest in stage of alveolar pulmonary edema, urgent medical help is required.
Stage III: Increased foaming
In the third stage, the breathing difficulties continue to worsen. More and more fluid collects in the bronchi. A visible symptom is increased foam formation, which is coughed up as whitish sputum. The breathing noises sound more and more rattling. A threatening lack of oxygen (hypoxemia) can occur. Signs of this are bluish discoloration of the lips and fingers (cyanosis).
Stage IV: Respiratory arrest (asphyxia)
Doctors refer to the life-threatening end-stage of pulmonary edema as asphyxia or respiratory failure. If those affected are not immediately supplied with oxygen, there is a risk of death from cardiac arrest.
Pulmonary edema can have very different causes. By far the most common cause is heart disease. In second place are kidney diseases. Other causes, such as lack of oxygen at high altitudes or other illnesses, are rare causes of pulmonary edema. More about the individual groups is below.
Cardiac Pulmonary Edema
Many people are unaware that the heart and lungs are closely connected by cardiopulmonary circulation. Very simply, the circuit looks like this: The oxygen-poor blood from the body reaches the lungs via the right ventricle. There it flows through the pulmonary capillaries along the alveoli. The blood releases carbon dioxide and absorbs vital oxygen. The freshly enriched blood then returns from the lungs to the heart and from the left ventricle back into the body.
The left ventricle is therefore responsible for the blood being pumped from the lungs into the body. If the left ventricle can no longer do this, the blood backs up into the pulmonary circulation. In addition, the right ventricle releases more and more blood into the lungs, as a result of which the pressure in the large and small blood vessels of the lungs continues to rise. Doctors speak of increasing hydrostatic pressure in the pulmonary veins and pulmonary capillaries. This pressure causes fluid from the blood to be forced through the walls of the blood vessels into the interstitial lung tissue, alveoli, and bronchioles.
Left heart failure (left heart failure) is the most common cause of cardiac pulmonary edema. In principle, however, pulmonary edema also occurs as a result of other severe cardiovascular diseases. These are above all:
Non-Cardiac Pulmonary Edema
If the cause of pulmonary edema is not in the heart, doctors speak of non-cardiac pulmonary edema. There are many possible triggers here.
- Kidney weakness and pulmonary edema: The kidneys play a decisive role in regulating the fluid balance in the body. With kidney weakness, less fluid is usually excreted. This also promotes pulmonary edema. In addition, kidney diseases sometimes excrete more proteins that should remain in the blood. Because these proteins make a significant contribution to binding the fluid in the blood vessels. Without these proteins, fluid can more easily escape from the blood vessels into the tissue: edema develops. Acute kidney failure is a life-threatening emergency that requires the fastest possible therapy. Lung edema can also result from chronic kidney weakness.
- Toxic pulmonary edema is caused by toxins or irritants. Typical for this form are, for example, the inhalation of irritant gases, nitric oxide, heroin, or gastric fluid.
- Allergic pulmonary edema is based on a particularly severe form of an allergic reaction, anaphylactic shock.
- The causes of high altitude pulmonary edema have not yet been clearly clarified. It sometimes arises in people who quickly ascend to great heights in the mountains. It occurs mainly at altitudes of more than 4,000 meters. About 7 percent of mountaineers are affected.
- So-called cerebral or neurogenic pulmonary edema is very rare. These pulmonary edema arise, for example, as a result of severe brain injuries or brain infections (encephalitis). Epilepsy can also be associated with cerebral pulmonary edema. In addition, in particular rare cases, severe forms of sunstroke lead to pulmonary edema.
For doctors or paramedics, the suspected diagnosis of pulmonary edema usually arises from the obvious breathing symptoms. The eavesdropping examination with the stethoscope (auscultation) and imaging examinations create clarity. A simple X-ray examination is sufficient to detect the pulmonary edema itself. When looking for the cause of the pulmonary edema, very different diagnostic methods are used, depending on the initial suspicion. These include ultrasound examinations of the heart (echocardiography) and laboratory tests of blood and urine.
The treatment of pulmonary edema is divided into immediate measures to alleviate breathing difficulties, drug therapy, and combating the triggering circumstances.
Immediate measures for pulmonary edema
Whether medical professionals, paramedics, or first aiders: If pulmonary edema is suspected, those affected should be positioned with the upper body upright. It is best for the patient to sit on a chair. Sitting or lying up has several positive effects:
- The respiratory muscles can relax and thus better support breathing.
- The pressure in the blood vessels in the lungs decreases because less blood normally gets to the chest when the legs are low.
- A firm holds while sitting usually helps reduce the agitation and anxiety typical of pulmonary edema.
In the event of a respiratory arrest or pronounced lack of oxygen (recognizable by blue lips or fingers paired with a lack of breathing), cardiopulmonary massage and resuscitation by first aiders can save lives. Paramedics or doctors can compensate for a lack of oxygen by ventilating with oxygen through a nasogastric tube. If necessary, doctors give a sedative against feelings of fear and restlessness.
In the case of severe pulmonary edema obviously caused by cardiac disease, medication to relieve the heart, such as nitroglycerine, catecholamines to improve expectoration such as dobutamine, diuretic agents such as furosemide, and anxiety-relieving opiates such as morphine are usually administered intravenously in the ambulance. In the case of toxic or allergic pulmonary edema, in particular, anti-inflammatory drugs from the active ingredient group of glucocorticoids such as prednisolone and dexamethasone are injected.
Cause-specific treatment of pulmonary edema
Cause-specific treatment of pulmonary edema usually takes place after admission to the hospital. These include, for example, the treatment of cardiovascular diseases or kidney weakness.
A general prognosis for pulmonary edema is not possible. Basically, the earlier professional treatment begins, the better the prospects. There are no official figures on the chances of survival. However, the statistics for cardiac insufficiency offer a clue. Of the approx. 450,000 heart failure patients treated in German hospitals each year, one in ten dies on average.
Breathing difficulties of unknown cause should always be examined by a doctor as early as possible. In particular, people with cardiovascular diseases, high blood pressure, lung diseases or kidney diseases should strictly adhere to the treatment recommendations – and if the symptoms change, see a doctor immediately to prevent pulmonary edema.