What causes water in the lungs?

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The lungs are the organ responsible for bringing oxygen into the body. While the membranes that line the lungs and chest cavity need fluid to lubricate them, the air sacs of the lungs need to stay dry. When the air sacs get filled with water, the body can no longer absorb oxygen from the lungs.

This condition is called pulmonary oedema and it can devastate the body if left untreated.

What is pulmonary edema?

According to the National Institutes of Health (NIH), pulmonary oedema (water in the lungs) is caused by fluid building up in the air sacs of the lungs. In order for the lungs to work properly, the air sacs must remain dry, so when fluid begins to enter the air sacs, the lungs must work harder to transport oxygen to the body. If it is left unchecked, this condition can lead to respiratory failure.

What causes pulmonary edema/water in the lungs?

Pulmonary oedema most typically happens because the heart or circulatory system is not functioning properly. There are four different ways to get pulmonary oedema, but the most common is cardiogenic, which is an internal condition. Cardiogenic pulmonary oedema, or congestive heart failure, according to the Mayo Clinic, occurs when the left ventricle of the heart is diseased or overworked. As a result, it stops pumping out enough oxygenated blood from your lungs, which increases pressure first on the left atrium of the heart, and then the pulmonary veins and capillaries. This forces fluid into the air sacs, and fills the lungs up with water.

The left ventricle can become weak or diseased due to a number of medical conditions, including coronary artery disease (hardened arteries), cardiomyopathy (when the left ventricle of the heart is damaged), heart valve problems and hypertension (high blood pressure).

What else causes pulmonary edema?

Apart from the cardiogenic conditions, there are outside forces that can contribute to water in the lungs. These outside forces are non-cardiogenic pulmonary oedema, alveolar and finally, unknown/multiple factors.

Non-cardiogenic pulmonary oedema can be caused by obstructions in the upper airway, seizures, overload of intravenous fluids, or acute respiratory distress syndrome (ARDS).

Alveolar conditions include aspiration (drowning), inhaling toxic gases, severe infections and possibly multiple blood transfusions.

Finally, the unknown or multiple causes are typically when things like severe head trauma, car accidents, haemorrhage or some other outside force causes the pulmonary oedema. Some people may experience pulmonary oedema due to sudden increases in altitude as well.


The initial symptom of water in the lungs is a shortness of breath or difficulty breathing. The NIH also lists a feeling of "air hunger" or "drowning" as a symptom, as well as excessive sweating, coughing up fluids, pale skin, restlessness, shortness of breath, wheezing and grunting or gurgling sounds when breathing. If you are coughing excessive amounts of phlegm, fluids or even the slightest amount of blood or bloody froth, seek medical care immediately.


Pulmonary oedema, no matter what the cause, is generally treated the same way. The first priority is to get enough oxygen into the body, so the immediate therapy is oxygenation. After that, the second priority is to flush out the water from the lungs and improve cardiac function. If an infection is causing the problem, then it is treated with antibiotics; however, if the problem is circulatory then the typical therapy treatments include water pills (diuretics to flush excess water from the body) and intravenous nitrates.