Where there is air in the lung tissue in a healthy person, water accumulates in certain diseases and is squeezed out of the small blood vessels. The fluid displaces the air and can cause severe shortness of breath. Read more about the development, typical symptoms as well as treatment of pulmonary edema here.
How does pulmonary edema develop?
Pulmonary edema can have several causes:
- Most commonly, it is caused by heart failure – if the left heart muscle does not pump enough blood onward into the large circulatory system, it backs up into the pulmonary circulation. This increases the pressure there and fluid is forced out of the smallest lung vessels (capillaries) into the interstitial tissue of the lungs (interstitium) and the alveoli (alveoli).
- Second most common cause in our country is renal insufficiency. If this is pronounced, there is overhydration of the body, resulting in the blood relatively more water than large solid substances, especially proteins. To balance the original ratio, water leaks from the blood vessels into surrounding tissues and deposited in the legs, abdomen (ascites) and lungs.
- But also lung diseases, pronounced allergic reactions or toxins can cause pulmonary edema. The reason in such cases is usually an increased permeability of the pulmonary capillaries.
- Altitude sickness, drowning in salt water and massive starvation are rather rare triggers in our latitudes.
What are the manifestations of pulmonary edema?
The symptoms and findings vary in severity depending on the stage of the disease. In the beginning, the fluid is only in the lung tissue itself, later the water enters the alveoli and even the small branches of the bronchi (bronchioles). Leading symptoms are shortness of breath with rapid, shallow, strained breathing and coughing; sufferers are very restless and often have chest pain. The shortness of breath may increase to the point that the patient thinks he or she is suffocating.
At this stage, pallor of the face and cyanosis (blue coloration of the lips, nails and mucous membranes) due to the lack of oxygen as well as frothy, sometimes slightly bloody sputum also appear. Then, even without a stethoscope, typical “bubbling” breathing sounds (so-called rales) can be heard. Without treatment, the disease leads to respiratory arrest with cardiovascular failure.
