What is Pulmonary Edema?
Pulmonary edema, or pulmonary congestion, is an abnormal condition in which fluid accumulates in the numerous air sacs of the lungs resulting in breathing difficulty. Pulmonary edema that develops instantly is called acute pulmonary edema and is a medical emergency. Chronic pulmonary edema develops slowly over time.
Causes of Pulmonary Edema
Pulmonary edema is often caused by cardiac problems but can also occur from non-cardiac causes.
Cardiogenic pulmonary edema(Congestive heart failure-related)
Cardiogenic pulmonary edema may be caused by the heart not being able to pump out blood effectively - a condition called congestive heart failure (CHF). This increases pressure in the blood vessels of the lungs causing fluid to exit these blood vessels and enter the air sacs.
Congestive heart failure may be caused by:
- Blockage of the blood vessels supplying the heart which may lead to a heart attack
- Weakness or thickness of the heart muscle (cardiomyopathy)
- Narrowed or leaking heart valves (mitral or aortic valves)
- Sudden, severe high blood pressure (hypertension)
Non-cardiogenic pulmonary edema
Pulmonary edema may have caused not related to any heart condition such as the following:
- Acute respiratory distress syndrome (ARDS): The lungs fill with fluid and white blood cells due to trauma, blood loss or infection
- Nervous system conditions: Can occur after damage to the nervous system such as following brain injury or brain surgery
- High altitudes: High-altitude pulmonary edema (HAPE) can develop in mountain climbers and people traveling to high altitude locations.
- Adverse drug reaction: Certain drugs such as heroin, cocaine, and aspirin may cause pulmonary edema.
- Pneumonia: This is an infection of the lung which causes inflammation in the air sacs and can lead to pulmonary edema.
- Lung damage associated with infection: Severe cases of a lung infection can cause damage to the lungs leading to pulmonary edema.
- Viral infections: Certain viral infections such as those caused by hantavirus and dengue virus are associated with pulmonary edema.
- Negative pressure pulmonary edema: Blockage in the upper airways causes a negative pressure in the lungs that may lead to pulmonary edema.
- Pulmonary embolism: Blood clots moving from blood vessels in the legs to the lungs can lead to pulmonary edema.
- Smoke inhalation: Smoke from a fire contains chemicals that damage the membrane separating the air sacs and the capillaries, allowing fluid to enter your lungs.
- Near-drowning: Pulmonary edema can be caused by inhaling water during a drowning episode. Immediate care can reverse this condition.
- Kidney failure: Failure to excrete fluid through the urinary system causes a build-up of pressure in the blood vessels that can lead to pulmonary edema.
Symptoms of Pulmonary Edema
Depending on the cause, the signs and symptoms of pulmonary edema can appear suddenly (acute) or develop over time (chronic).
Symptoms of Acute Pulmonary Edema:
- Extreme shortness of breath or difficulty breathing (dyspnea) that intensifies with activity or when lying down
- A feeling of suffocating or drowning that increases when lying down
- Wheezing or gasping for breath
- Moist, cold skin
- Bluish discoloration of the lips
- Rapid and irregular heart rate (palpitations)
- Excessive sweating
- Feelings of suffocation
- Chest pain
Symptoms of Chronic Pulmonary Edema:
- Shortness of breath when physically active
- Difficulty breathing with exertion or when lying flat
- Rapid weight gain, especially in the legs
- Swelling in your lower extremities
- Waking up the night with severe sudden breathlessness (paroxysmal nocturnal dyspnea)
Diagnosis of Pulmonary Edema
Your doctor will make a diagnosis based on your symptoms, medical history, physical examination, and certain tests. On physical examination your doctor will note any:
- Increased heart rate
- Rapid breathing
- Crackling sound from your lungs
- Abnormal heart sounds
Tests that may be performed to diagnose pulmonary edema include:
- Chest X-ray: A chest X-ray will likely be the first test to identify pulmonary edema as the cause of your shortness of breath.
- Pulse oximetry: A sensor is attached to your finger or ear and light is used to determine the percentage of oxygen in your blood.
- Electrocardiogram (ECG): This test provides detailed information about your heart by measuring its electrical activity.
- Cardiac catheterization: This is a minimally invasive procedure performed to identify cardiovascular causes of pulmonary edema. A catheter is inserted through a blood vessel to reach your heart and a dye is injected to enhance X-ray imaging.
- Blood tests: Blood tests may be performed to determine blood count, the concentration of oxygen and carbon dioxide in the arterial blood, as well as kidney and thyroid function.
The first treatment for pulmonary edema is oxygen through a face mask or tiny plastic tubes in the nose. Medications may be administered depending on your condition and the cause of your pulmonary edema. These include:
- Diuretics to decrease the pressure caused by excess fluid in your heart and lungs
- Morphine, a narcotic used to relieve shortness of breath and anxiety
- Blood pressure medications if you develop high or low blood pressure with pulmonary edema and to reduce the load on the heart
To decrease the risk of pulmonary edema, your doctor may recommend lifestyle changes including:
- Controlling medical conditions such as high blood pressure and diabetes
- Avoiding drugs, allergens or high altitudes that can cause further damage to your lungs
- Quitting smoking
- Eating a healthy diet
- Maintaining a healthy weight and exercising regularly