What Is Pulmonary Edema and Why Does It Happen?

Pulmonary edema is when there is an abnormal buildup of fluid in the lungs that makes it difficult to breathe.

This happens when the heart is not able to pump blood efficiently, causing it to stagnate in the veins that carry it to the lungs.

As the pressure in these blood vessels increases, the fluid is pushed toward the air spaces in the lungs (alveoli). This reduces the normal movement of oxygen through the lungs and makes it difficult to breathe.

This disorder can be acute (start suddenly) or chronic (develop slowly). Acute pulmonary edema is considered a medical emergency that requires immediate attention.

It can also be differentiated into two categories: cardiogenic or hemodynamic pulmonary edema (the most common type, described above), and noncardiogenic pulmonary edema or lung injury.

When edema is cardiogenic, it can be caused by:

• Heart attacks or any heart disease that causes myocardial weakness or stiffness
• Patent or narrow heart valves
• Sudden, severe high blood pressure
  

When edema is not cardiogenic, it can be caused by:

• Certain medications
• Exposure to high altitudes
• Kidney failure
• Narrowing of the arteries that carry blood to the kidneys
• Lung damage from certain toxins
• Respiratory distress syndrome or pulmonary embolism
• Inhaling smoke
• Nervous system disorder
• Serious infections

The growing amount of fluid in the lungs from the edema prevents oxygen from passing into the bloodstream. This can cause the following symptoms to worsen until you receive treatment:

• Difficulty breathing while lying down, also known as orthopnea
• Feeling of “shortness of breath” or “asphyxia,” called paroxysmal nocturnal dyspnea
• Rhonchi or gurgling or wheezing sounds with breathing
• Decreased mental clarity or consciousness
• Swelling of the abdomen or legs
• Pale skin
• Excessive sweating

What to do

Specialists say that how fast this condition improves depends on the cause. For example, some cases require long-term use of a ventilator along with medications. But what is clear is that without treatment, it can be fatal.

Pulmonary edema is usually treated in emergency rooms or hospitals and may even require a stay in the intensive care unit.

Nonetheless, this condition can be prevented by incorporating certain habits:

• Managing your blood pressure and cholesterol levels
• Reducing alcohol consumption and not smoking
• Following a diet rich in heart-healthy foods
  
• Doing regular physical activity
• Maintaining a healthy weight
• Managing stress and anxiety

Source: American Heart Association; National Library of Medicine; Mayo Clinic.