Pulmonary Edema: Causes, Signs, Symptoms, Types, Diagnosis, Prevention and Treatment

It occurs when the alveoli are filled with excess fluid that leaves the blood vessels of the lung instead of air. This interferes with gas exchange and can cause respiratory failure.

Pulmonary edema can be acute (sudden onset) or chronic (occurs more slowly over time). If it is acute, it is classified as a medical emergency that needs immediate attention. The term edema is from the Greek οἴδημα (oídēma, “swelling”).

Pulmonary edema is a condition that involves the accumulation of fluid in the lungs and sudden onset (acute) pulmonary edema is a medical emergency. Sometimes, a chest x-ray can help diagnose pulmonary edema.

Causes of pulmonary edema

The most common cause of pulmonary edema is congestive heart failure , in which the heart can not keep up with the demands of the body.

During normal breathing, the small alveoli of the lungs fill with air. The oxygen is absorbed and the carbon dioxide is expelled. Pulmonary edema occurs when the alveoli flood.

When the alveoli are flooded, two problems occur:

  • The bloodstream can not get enough oxygen.
  • The body can not eliminate carbon dioxide properly.

Common causes include:

  • Pneumonia .
  • Sepsis (infection of the blood).
  • Exposure to some chemicals.
  • Organic insufficiency that causes accumulation of fluid: congestive heart failure, renal failure or liver cirrhosis .
  • Feeling of drowning.
  • Inflammation.
  • Trauma.
  • Reaction to certain medications.
  • Drug overdose.

In addition to direct injury to the lungs, as in acute respiratory distress syndrome, other causes include:

  • Brain injuries such as brain hemorrhage , stroke , head injury, brain surgery, tumor or seizure.
  • High altitude
  • Blood transfusion.

Signs and symptoms of pulmonary edema

The development of pulmonary edema may be associated with symptoms and signs of “fluid overload”.

This is a non-specific term to describe the manifestations of right ventricular failure in the rest of the body.

It includes peripheral edema (swelling of the legs, in general, of the “sting” variety, in which the skin takes time to return to normal) when it is pressed.

Elevated jugular venous pressure and hepatomegaly, where the liver is enlarged and may be sensitive or even throbbing.

Other common symptoms may include easy tiredness, shortness of breath of development faster than normal with habitual activity (dyspnea on exercise), rapid breathing (tachypnea), dizziness or weakness.

Acute pulmonary edema causes significant breathing difficulties and may appear without warning. This is an emergency and requires immediate medical attention. Without the right treatment and support, it can be fatal.

Along with breathing difficulties, other signs and symptoms of acute pulmonary edema may include:

  • Cough, often with a pink foamy sputum.
  • Excessive sweating
  • Anxiety and restlessness
  • Feelings of suffocation.
  • Pale skin.
  • Wheezing
  • Rapid or irregular heart rhythm (palpitations).
  • Chest pain.

If the pulmonary edema is chronic, the symptoms are usually less severe until the body’s system can no longer compensate. Typical symptoms include:

  • Difficulty breathing when lying down ( orthopnea ).
  • Swelling (edema) of feet or legs.
  • Rapid weight gain due to the accumulation of excess fluid.
  • Dyspnoea paroxysmal nocturnal, sudden episodes of severe breathlessness at night.
  • Fatigue.
  • Increased difficulty in breathing with physical activity.

Pulmonary edema or plural effusion

Pulmonary edema occurs when fluid builds up inside the lungs, in the alveoli, which makes breathing difficult. The plural effusion also involves fluid in the lung area, and is sometimes called ” water in the lungs .”

However, in pleural effusion, water fluid accumulates in the layers of the pleura that are outside the lungs. It can be a consequence of heart failure, cirrhosis or pulmonary embolism. It can also happen after a heart surgery.

Pulmonary edema or pneumonia

Pulmonary edema may overlap with pneumonia, but it is a different condition. Pneumonia is an infection that often occurs as a complication of a respiratory infection, such as the flu.

It can be difficult to distinguish between the two. If the person or a family member can provide a detailed medical history, this will make it easier for a doctor to make the correct diagnosis and provide the appropriate treatment.

Types

Classically it is cardiogenic (left ventricle) but fluid can also accumulate due to damage to the lung. This damage can be a direct injury or injury mediated by high pressures within the pulmonary circulation.

When it is caused directly or indirectly by increased left ventricular pressure, pulmonary edema may form when the average pulmonary pressure rises from normal from 15 mmHg to more than 25 mmHg.

In general terms, the causes of pulmonary edema can be divided into cardiogenic and non-cardiogenic. By cardiogenic convention it refers to the causes of the left ventricle.

Cardiogenic

Pulmonary edema due to a direct problem with the heart is called cardiogenic.

Congestive heart failure is a common cause of cardiogenic pulmonary edema; In this condition, the left ventricle can not pump enough blood to meet the body’s needs.

This causes a buildup of pressure in other parts of the circulatory system, forcing fluids to enter the alveoli of the lungs and other parts of the body.

Other problems related to the heart that can lead to pulmonary edema include:

Fluid overload : This may be the result of kidney failure or intravenous fluid therapy.

Hypertensive emergency : a severe increase in blood pressure that puts excessive pressure on the heart.

Pericardial effusion with tamponade : accumulation of fluid around the sac that covers the heart. This can decrease the heart’s ability to pump.

Severe arrhythmias : this may be tachycardia (rapid heartbeat) or bradycardia (slow heartbeat). Either one can cause poor cardiac function.

Severe heart attack : this can damage the heart muscle and make it difficult to pump.

Abnormal heart valve : it can affect the flow of blood that leaves the heart.

The causes of pulmonary edema that are not due to poor cardiac function are called non-cardiogenic; They are usually caused by acute respiratory distress syndrome .

This is a severe inflammation of the lungs that leads to pulmonary edema and significant breathing difficulties.

Others

Lung injury can also cause pulmonary edema due to injury to the vasculature and lung parenchyma . Acute acute respiratory failure syndrome (ALI-ARDS) encompasses many of these causes, but may include:

Inhalation of hot or toxic gases. Aspiration, for example, gastric fluid. Reperfusion injury, that is, postpulmonary thromboendartectomy or lung transplantation. Pulmonary contusion, that is, high energy trauma (for example, vehicle accidents).

Reexpansion, that is, after a high-volume thoracentesis, resolution of pneumothorax, post-decortication, elimination of endobronchial obstruction, in fact a form of negative pressure pulmonary edema.

Circulatory overload associated with transfusion (TACO) occurs when multiple transfusions of blood or blood products (plasma, platelets, etc.) are transfused over a short period of time.

Transfusion-associated acute lung injury (TRALI) is a specific type of transfusion injury of blood products that occurs when the donor’s plasma contains antibodies to the donor, such as anti-HLA or anti-neutrophil antibodies. .

Infection or severe inflammation that can be local or systemic. This is the classic form of acute lung injury.

Arteriovenous malformation: Hantavirus pulmonary syndrome.

Sudden pulmonary edema

Sudden pulmonary edema (FPE) is a rapid-onset pulmonary edema.

In most cases it is precipitated by acute myocardial infarction or mitral regurgitation, but it can be caused by aortic regurgitation, heart failure or almost any cause of elevated left ventricular filling pressure.

The treatment of sudden pulmonary edema should be directed to the underlying cause, but the pillars are ensuring oxygenation, diuresis and decreased pulmonary circulation pressures.

It is believed that the recurrence of sudden pulmonary edema is associated with hypertension and may signify stenosis of the renal artery. The prevention of recurrence is based on the management of hypertension, coronary artery disease, renovascular hypertension and heart failure.

Diagnosis

The patient will first undergo a physical examination. The doctor will use a stethoscope to listen to the lungs for crackles and rapid breathing, and the heart for abnormal rhythms.

Low oxygen saturation and alteration of arterial gas readings support the proposed diagnosis by suggesting a pulmonary shunt.

The chest radiograph will show fluid in the alveolar walls, Kerley B lines, increased vascular shading in a classic perilesotial pattern of batwing, deviation of the upper lobe (increased blood flow to the upper lung) and possibly pleural effusions.

In contrast, patchy alveolar infiltrates are more typically associated with non-cardiogenic edema

Lung ultrasound, used by a health care provider at the point of care, is also a useful tool for diagnosing pulmonary edema.

Not only is it accurate, but it can quantify the degree of pulmonary water, track changes over time and differentiate between cardiogenic and non-cardiogenic edema. Low levels of BNP (<100 pg / ml) suggest an unlikely cardiac cause.

Blood tests will be done to determine oxygen levels in the blood; The doctor will often order other blood tests, which include:

  • Electrolyte levels.
  • Function of the kidney.
  • Liver function
  • Blood counts and blood markers of heart failure.

An ultrasound of the heart, an echocardiogram and an electrocardiogram (EKG) can help determine the condition of the heart.

Prevention of pulmonary edema

In those with underlying heart disease, effective control of congestive symptoms prevents pulmonary edema.

Patients at increased risk of developing pulmonary edema should follow their doctor’s advice to keep their condition under control.

If the problem is congestive heart failure, following a healthy and balanced diet and maintaining a healthy body weight can help reduce the risk of future episodes of pulmonary edema.

Regular exercise also improves the health of the heart as it does:

Reduce the consumption of salt : excess salt can lead to water retention. This increases the work that the heart has to do.

Decreased cholesterol levels : high cholesterol can cause fatty deposits in the arteries, which in turn increases the risk of heart attack and stroke and, therefore, pulmonary edema.

Stop smoking : tobacco increases the risk of a number of diseases, including heart disease, lung diseases and circulatory problems.

Altitudinally induced pulmonary edema can be minimized by a gradual ascent, taking medications before traveling and avoiding excessive effort while moving at higher altitudes.

Treatment for pulmonary edema

The treatment of pulmonary edema generally focuses on improving respiratory function and dealing with the source of the problem. It usually includes providing oxygen and additional medications to treat the underlying conditions.

Pulmonary edema can be acute or chronic. To raise oxygen levels in the patient’s blood, oxygen is administered through a mask or tips, small plastic tubes in the nose.

A breathing tube can be placed in the windpipe if a respirator is necessary.

If the tests show that the pulmonary edema is due to a problem in the circulatory system, the patient will be treated with intravenous medications to help eliminate the volume of fluid and control blood pressure.

Cardiogenic pulmonary edema

Acute cardiogenic pulmonary edema often responds quickly to medical treatment. Positioning yourself upright can relieve symptoms.

Loop diuretics such as furosemide or bumetanide are administered , often together with morphine or diamorphine to reduce respiratory distress.

Both diuretics and morphine can have vasodilating effects, but specific vasodilators (particularly intravenous glyceryl trinitrate or ISDN) can be used provided blood pressure is adequate.

It has been shown that continuous positive pressure in the airways and positive pressure in the airways at two levels (BIPAP / NIPPV) reduces the need for mechanical ventilation in people with severe cardiogenic pulmonary edema and can reduce mortality.