Pulmonary Edema

Definition

Pulmonary edema is a condition in which fluid accumulates in the lungs, usually because the heart's left ventricle does not pump adequately.

Description

The build-up of fluid in the spaces outside the blood vessels of the lungs is called pulmonary edema. Pulmonary edema is a common complication of heart disorders, and most cases of the condition are associated with heart failure. Pulmonary edema can be a chronic condition, or it can develop suddenly and quickly become life threatening. The life-threatening type of pulmonary edema occurs when a large amount of fluid suddenly shifts from the pulmonary blood vessels into the lung, due to lung problems, heart attack, trauma, or toxic chemicals. It can also be the first sign of coronary heart disease.

In heart-related pulmonary edema, the heart's main chamber, the left ventricle, is weakened and does not function properly. The ventricle does not completely eject its contents, causing blood to back up and cardiac output to drop. The body responds by increasing blood pressure and fluid volume to compensate for the reduced cardiac output. This, in turn, increases the force against which the ventricle must expel blood. Blood backs up, forming a pool in the pulmonary blood vessels. Fluid leaks into the spaces between the tissues of the lungs and begins to accumulate. This process makes it more difficult for the lungs to expand. It also impedes the exchange of air and gases between the lungs and blood moving through lung blood vessels.

Causes and symptoms

Most cases of pulmonary edema are caused by failure of the heart's main chamber, the left ventricle. It can be brought on by an acute heart attack, severe ischemia, volume overload of the heart's left ventricle, and mitral stenosis. Non-heart-related pulmonary edema is caused by lung problems like pneumonia, an excess of intravenous fluids, some types of kidney disease, bad burns, liver disease, nutritional problems, and Hodgkin's disease. Non-heartrelated pulmonary edema can also be caused by other conditions where the lungs do not drain properly, and conditions where the respiratory veins are blocked.

Early symptoms of pulmonary edema include:

• shortness of breath upon exertion
• sudden respiratory distress after sleep
• difficulty breathing, except when sitting upright
• Coughing

In cases of severe pulmonary edema, these symptoms will worsen to:

• labored and rapid breathing
• frothy, bloody fluid containing pus coughed from the lungs (sputum)
• a fast pulse and possibly serious disturbances in the heart's rhythm (atrial fibrillation, for example)
• cold, clammy, sweaty, and bluish skin
• a drop in blood pressure resulting in a thready pulse

Content licensed from:

Author Info: Lori De Milto, The Gale Group Inc., Gale, Detroit, Gale Encyclopedia of Medicine, 2002

This feature is for informational purposes only and should not be used to replace the care and information received from your healthcare provider. Please consult a healthcare professional with any health concerns you may have.