The lungs contain many small, elastic air sacs known as alveoli. These alveoli take in oxygen with each breath and release carbon dioxide. The exchange of gases typically takes place without any problems.
But in certain circumstances, the air sacs get filled with fluid instead of air, preventing oxygen from being absorbed into the bloodstream. This condition is known as Pulmonary Edema.
Pulmonary edema, also known as pulmonary congestion or lung congestion, is a medical condition in which the lungs fill with fluid. It is often characterized by shortness of breath due to the body’s inability to get enough oxygen.
Several things can cause pulmonary edema, but most of it has to do with the heart, a condition known as cardiogenic pulmonary edema.
Treatment options for pulmonary edema usually focus on improving respiratory function and dealing with the underlying cause of the problem. Timely treatment for the condition can improve possible outcomes.
Causes of Pulmonary Edema
Cardiogenic Pulmonary Edema
The heart is composed of two upper (the right and left atria) and two lower chambers (the right and left ventricle). The upper chambers receive blood coming into the heart and pump it into the lower chambers, which pumps it out of the heart.
The heart valves keep blood flowing in the correct direction, and these act as the gates into the chambers. Pulmonary edema that occurs as a result of problems with the heart is known as cardiogenic pulmonary edema. It is pulmonary edema caused by increased pressures in the heart.
This condition typically occurs when the overworked or diseased ventricle is not able to pump out enough of the blood it receives from the lungs (congestive heart failure).
This results in increased pressure inside the left atrium and subsequently in the veins and capillaries in the lungs, causing fluid to be pushed through the capillaries into the alveoli.
Other heart-related issues that can lead to pulmonary edema include:
- Hypertensive emergency – this is a severe increase in blood pressure that puts excessive strain on the heart.
- Heart attack – this can damage the heart muscle, making it difficult to pump blood.
- Severe arrhythmias – this can be bradycardia (slow heartbeat) or tachycardia (fast heartbeat). Either can result in poor heart function.
- Fluid overload – which may occur as a result of kidney failure or intravenous fluid therapy.
- Abnormal heart valves – can affect the flow of blood out of the heart.
Other common causes;
Other causes of pulmonary edema include:
- Organ failure such as liver cirrhosis, kidney failure, congestive heart failure
- Exposure to toxic chemicals
- Drug overdose
- Smoke inhalation
- Reaction to certain chemicals
- Brain surgery
- High altitude
- Blood transfusion
- Brain bleeding and tumor
Signs and Symptoms of Pulmonary Edema
Your body may struggle to gain oxygen in cases of pulmonary edema. This is due to the increase in fluid in the lungs that prevents oxygen from moving into the bloodstream.
Symptoms of this condition may continue to deteriorate until treatment occurs. Symptoms depend on the type of pulmonary edema.
Acute pulmonary edema
This comes on suddenly and can be life-threatening. The symptoms include
- Sudden shortness of breath, especially after activity or while lying down.
- Feeling like you’re drowning or your heart is dropping
- Difficulty breathing with a lot of sweating
- Wheezing and gasping
- Coughing up frothy pink spit
- Rapid, irregular heartbeats
- Dizziness, fatigue and excessive sweating which can signal a drop in blood pressure
Chronic pulmonary edema
The symptoms of chronic pulmonary edema include:
- Shortness of breath when being physically active
- Rapid weight gain especially in the legs
- Difficulty breathing when lying down
- Gasping and wheezing
- Swelling in the lower part of the body
- Exhaustion and fatigue
High-altitude pulmonary edema
Symptoms of pulmonary edema due to altitude sickness, or not getting enough oxygen in the air include:
- Shortness of breath after physical activity or during rest
- Rapid, irregular heartbeat
- Difficulty walking uphill and on flat surfaces
A doctor performs the diagnosis of pulmonary edema. The patient first undergoes a physical examination. After this, the doctor uses a stethoscope to listen to the lungs for rapid breathing, and the heart for abnormal rhythms.
Blood tests will also be carried out to determine levels of oxygen in the blood. Asides the blood test, the doctor will often order other tests for liver function, electrolyte levels, kidney function, blood counts, and blood markers of heart failure.
An ultrasound of the heart will also be carried out using an echocardiogram and an electrocardiogram (EKG). This can help determine the condition of the heart.
A chest X-ray may be used to detect the presence of fluid in or around the lungs and to check the size of the heart.
The treatment of pulmonary edema depends on its cause and severity. Most cases of cardiogenic pulmonary edema are treated by using diuretics (water pills) as well as other medications for heart failure.
In some cases, appropriate treatment can be achieved using taking oral medications. In severe cases of pulmonary edema where the condition is not responsive to oral medications, hospitalization and intravenous diuretic medications may be required.
Treatment for noncardiac causes of pulmonary edema varies depending on the purpose. For example, pulmonary edema caused by sepsis (blood infection) is treated with antibiotics.
In cases where oxygen in the blood is too low, oxygen supplementation may be necessary. Severe conditions like acute respiratory distress syndrome (ARDS) may require that the patient be placed on mechanical breathing support while treatment for pulmonary edema is ongoing.
Patients with an increased risk of developing lung edema must follow their doctor’s advice to keep their condition under control. The following are ways by which the disease can be prevented:
- Reducing salt intake: Excess salt can lead to water retention, increasing the heart’s workload.
- Reducing cholesterol levels: High levels of cholesterol can lead to fatty deposits in the arteries, resulting in an increased risk of heart attack and stroke and, therefore, pulmonary edema.
- Stop smoking: Smoking tobacco products increases the risk of several diseases, including heart disease, lung disease, and circulatory problems.
Pulmonary edema due to high altitudes can be minimized by making a gradual ascent, taking necessary medications before traveling, and avoiding excess exertion while going up to higher elevations.