The causes of pulmonary edema

1. What is pulmonary edema?

Pulmonary edema, also called lung congestion, is a condition caused by excess fluid in the lungs. This fluid accumulates in many air sacs in the lungs, leading to difficulty breathing and pleural effusion.
In most cases, heart problems lead to pulmonary edema. However, fluid can accumulate in the lungs for various reasons, including pneumonia, exposure to certain toxins and medications, chest trauma, and travel or exercise at high altitudes.
Sudden-onset pulmonary edema (acute pulmonary edema) is a medical emergency that requires immediate care because pulmonary edema can sometimes be fatal. Treatment for pulmonary edema varies depending on the cause, but generally includes supplemental oxygen and medications.

2. Symptoms of pulmonary edema

The signs and symptoms of pulmonary edema, or lung congestion, can appear suddenly or develop over time, depending on the type of pulmonary edema.

2.1. Symptoms of acute pulmonary edema (sudden onset)

• Difficulty breathing or shortness of breath that worsens with activity or when lying down.
• Feeling of suffocation or drowning that worsens when lying down.
• Cough producing foamy sputum, potentially tinged with blood.
• Wheezing or gasping for breath.
• Cold skin.
• Anxiety, restlessness, or a feeling of fear.
• Slightly bluish lips.
• Rapid and irregular heart rate (palpitations).
• Symptoms of chronic pulmonary edema (long-term).
• Difficulty breathing with activity or when lying flat.
• Waking up at night with coughing or shortness of breath that can be relieved by sitting up.
• Increased difficulty breathing with physical activity.
• Wheezing.
• Rapid weight gain.
• Swelling in the lower limbs.
• Fatigue.
• New or worsening cough.

2.2. Signs and symptoms of high-altitude pulmonary edema (HAPE)

High-altitude pulmonary edema can occur in both adults and children who travel or exercise at high altitudes. The signs and symptoms are similar to those of acute pulmonary edema, including:

• Headache, which may be the first symptom.
• Shortness of breath with activity, which worsens at rest.
• Reduced exercise capacity compared to usual.
• Dry cough at first.
• Later, the cough may produce pink, frothy sputum.
• Weakness.
• Chest pain.
• Mild fever.
• The signs and symptoms of high-altitude pulmonary edema (HAPE) often tend to worsen at night.

3. Causes of Pulmonary Edema

There are many causes of pulmonary edema. It is commonly believed in folk wisdom that bathing at night is a bad habit that causes fluid in the lungs, but this is not true. Pulmonary edema can be caused by various factors, and the causes are often determined based on the color of the fluid, microbiological tests, cytology, biochemistry, X-rays, etc., such as:

• Lemon-yellow fluid (Exudative pleural effusion): The main causes are pulmonary tuberculosis, pneumonia, pulmonary artery involvement, liver abscess, or pericarditis, etc.
• Clear fluid (Transudative pleural effusion): Commonly seen in conditions causing fluid retention in the body, especially in nephrotic syndrome, malnutrition, heart failure, cirrhosis, and swollen thyroid.
• Pink or red fluid (Hemothorax - pneumothorax): This is a symptom of lung cancer or metastasis from other cancers to the lungs. This type of fluid often develops and recurs rapidly after fluid drainage, leading to significant difficulty in breathing.
• Pus-like fluid (Purulent effusion): Caused by primary infection in the pleural tissue or secondary infection of pleural effusion, with abscesses near the pleura.
• White, rice-water-like or sparkling yellow fluid: Caused by compression of the thoracic duct by tumors and chest trauma or compression of the subclavian vein. The mechanism of this type of fluid is often unclear.
• Cirrhosis and ascites, and chronic kidney failure.
• Caused by parasites.
• Systemic diseases such as rheumatoid arthritis, systemic lupus erythematosus.

Additionally, when cancer cells metastasize to the pleura, they can block the pulmonary vessels. It is also possible that this is the result of radiation therapy for cancer treatment.
Some cancers that may cause pulmonary edema include:

• Breast cancer.
• Lung cancer.
• Cervical cancer.
• Ovarian cancer.

4. When to See a Doctor

Sudden pulmonary edema (acute pulmonary edema) is life-threatening. Call 911 or seek emergency medical assistance if you experience any of the following acute signs and symptoms:

• Shortness of breath, especially if it occurs suddenly.
• Difficulty breathing or feeling suffocated (dyspnea).
• Bubbling sounds, wheezing, or gasping while breathing.
• Pink, frothy sputum when coughing.
• Shortness of breath accompanied by excessive sweating.
• Skin turning blue or gray in color.
• Confusion.
• Significant drop in blood pressure leading to dizziness, lightheadedness, weakness, or sweating.
• Any pulmonary edema symptoms worsening suddenly.

Do not attempt to drive yourself to the hospital. Instead, call 911 or seek emergency medical care and wait for help.

5. Complications of Pulmonary Edema

People with pulmonary edema may experience several dangerous complications, such as:

• Difficulty breathing.
• Swelling in the legs, feet, and abdomen.
• Fluid accumulation in the membranes surrounding the lungs (pleural effusion)
  Obstruction and swelling of the liver.
• Immediate treatment is necessary for acute pulmonary edema to prevent death.

6. Interventions for Pulmonary Edema

To treat pleural effusion, doctors will identify the underlying cause of fluid accumulation in the pleural cavity, and develop an appropriate treatment strategy.

6.1. Pleural Fluid Aspiration

This is the most common treatment method. It helps remove excess fluid, making it easier for the patient to breathe.

6.2. Pleural Drainage

This method is used when the patient has pleural effusion with pus, blood, or air. A special tube (drain) made of silicone is inserted through the skin into the pleural cavity and connected to a negative pressure suction system to drain out pus and blood.

6.3. Medical Treatment

The specific medical treatment depends on the underlying cause:

• If the cause is an infection (purulent pleuritis), antibiotics will be prescribed.
• If tuberculosis is the cause, anti-tuberculosis medication will be administered.
• If cancer is the cause, chemotherapy will be used, and pleural adhesions may be induced to prevent rapid recurrence of fluid buildup.

6.4. Supportive Treatment

• Respiratory support: fluid drainage and oxygen therapy through a nasal cannula.
• Pain relief and fever reduction with paracetamol.
• Bed rest with light, easily digestible foods that provide adequate energy and nutrition.
• Breathing exercises as instructed by the doctor.

7. Prevention of water retention in the lungs

Patients with pulmonary edema often feel weak and fatigued, so strengthening their physical condition through a scientific diet will help them better cope with the disease. You can prevent pulmonary edema by:

• Following a healthy diet with protein-rich foods like meat, eggs, milk, and fruits high in vitamin C, such as oranges and grapefruits, to ensure sufficient energy intake.
• Managing your weight.
• Exercising regularly.
• Avoiding smoking.
• Limiting salt and alcohol intake.
• Managing stress.

To prevent HAPE, ascend to high altitudes gradually. While recommendations vary, most experts advise increasing altitude by no more than 1,000 to 1,200 feet (about 300 to 360 meters) per day once you reach 8,200 feet (around 2,500 meters).
Some climbers use prescription medications like acetazolamide or nifedipine (Adalat CC, Procardia) to help prevent HAPE symptoms. Start taking the medication at least one day before ascending. Consult your doctor about how long you should continue the medication after reaching your destination altitude.
When dealing with pulmonary edema, patients often experience anxiety and fear. Family members should provide reassurance, closeness, and encouragement. Encourage patients to express their fears and anxieties about the disease. Explain to them the importance of maintaining a positive mindset and following the doctor's instructions for faster recovery and potential complete healing.
Additionally, maintaining a calm, clean, and ventilated environment in the patient's room will help the patient with pulmonary edema  rest and relax, promoting a better treatment outcome.
There are various treatment options for pulmonary edema, and doctors will recommend one or combine several approaches:

• Antibiotics or cancer treatment may be necessary.
• Fluid aspiration and drainage from the pleural cavity to minimize the disease’s negative impact on health.
• Traditional medicine may be used to enhance lung function and safely drain fluid.
  If the pleural cavity contains excessive fluid, surgery to drain blood, pus, or other fluids may be necessary.

Pulmonary edema is a serious condition that can significantly affect health. However, when diagnosed and treated promptly, patients have the opportunity to live healthily and improve their quality of life.

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