Pulmonary Edema

Depending on how quickly the illness sets in, pulmonary edema can be divided into two types:

• Acute pulmonary edema: The symptoms of pulmonary edema may appear suddenly and can be extremely severe. If not treated, acute pulmonary edema can be fatal. The symptoms can present as:
  • Extreme shortness of breath
  • Gasping for air
  • Cough with frothy sputum
  • Bluish skin discolouration
  • Chest pain
• Chronic pulmonary edema: The symptoms of pulmonary edema can sometimes develop over a long period of time and can progressively turn worse with time. The symptoms of chronic pulmonary edema can present as:
  • Shortness of breath throughout the day (especially while you’re active)
  • Shortness of breath while laying down
  • Rapid weight gain
  • Swelling in feet, ankles and toes

The symptoms of pulmonary edema are:

• Extreme shortness of breath
• Cold clammy skin
• Wheezing sound on breathing
• Coughing
• Orthopnea (excessive shortness of breath on lying down) 
• Paroxysmal nocturnal dyspnea (excessive coughing and shortness of breath during the night)
• Swelling in the lower extremities
• Rapid weight gain
• Anxiety

Pulmonary edema may occur as a result of heart disease, lung disease, kidney failure, accidental drowning and altitude sickness, among other reasons. When the cause is related to the heart, it is known as cardiogenic pulmonary edema.

The cardiogenic causes of edema in the lungs are:

• Heart failure: A condition where the heart fails to pump blood to the body, leading it to the state of heart failure.
• Mitral valve regurgitation: Usually the blood flows unidirectionally, that is, from the left atrium (upper chamber) to the left ventricle (lower chamber) of the heart. Both the chambers of the heart are separated with the help of door like structures called mitral valves. When there is damage to these mitral valves, the blood starts to move in the opposite direction, that is, from the left ventricle to the left atrium. This is called mitral valve regurgitation - a type of valvular heart disease which leads to pulmonary edema as it increases the pressure of fluid present in the blood vessels.
• Aortic stenosis: Aortic stenosis refers to the narrowing of the opening of the aortic valve. This leads to increased pressure within the blood vessels, which can cause a pulmonary embolism (blood clot in the lungs that obstructs normal blood flow).
• Arrhythmia: Irregular heartbeats, medically called arrhythmia, can cause poor functioning of the heart which can lead to pulmonary edema.
• Cardiomyopathy: Stiffening or weakening of the heart muscles is medically called cardiomyopathy and it can lead to the poor functioning of the heart. This can lead to increased pressure on the blood vessels, thus causing pulmonary edema.
• Coronary artery disease: Blockage or narrowing of arteries due to any blood clot or buildup of cholesterol is called coronary artery disease. This increases pressure on the blood vessels, thus leading to pulmonary edema.

The non-cardiogenic pulmonary edema causes are:

• Pulmonary thromboembolism: When a blood clot floats through the bloodstream and gets lodged in the lungs, it is called a pulmonary embolism. This can lead to a build-up of fluid in the lungs. 
• Pleurisy: Pleurisy is the inflammation of the pleura, the outer layer covering the lungs. It can lead to fluid build-up in the lungs.
• Activity related: Inhaling water while swimming or incase of accidental drowning can cause non-cardiogenic pulmonary edema. It can be reversed with immediate attention.
• Inhalation of toxin: Toxins like ammonia or even smoke can directly impact your lungs.
• Kidney failure: Our kidneys get rid of the excess fluid and waste material of the body. When the kidneys can no longer perform this function, fluid can build-up in the blood vessels resulting in pulmonary edema. 
• High altitude pulmonary edema (HAPE): People who climb mountains or travel to high-altitude locations at elevations above 8,000 feet are at risk of developing HAPE. If not treated immediately, it can be fatal.
• Drugs: Overdose of aspirin can lead to its toxicity, which can cause pulmonary edema.
• Acute respiratory distress syndrome: Respiratory distress syndrome is rare in adults. Though when it occurs, acute respiratory distress syndrome (ARDS) is a serious disorder marked by a sudden filling up of lungs with fluids and an increase in inflammatory white blood cells. ARDS can occur due to any trauma, sepsis, pneumonia or severe bleeding.

The diagnosis of pulmonary edema can be done with the help of the following measures:

• Physical exam: The doctor will listen to the lungs with a stethoscope; a wheezing sound from the lungs can be a sign of pulmonary edema. 
• Chest X-rays: X-ray can help look for fluid that could be present in the pleural space (space between the layers covering the lungs). 
• Ultrasound: An ultrasound can help find any fluid or abnormality in the lungs.
• CT scan: CT scan can help in finding the areas filled with fluids. 
• Thoracentesis: A small sample of pleural fluid is taken from the chest cavity and examined under a microscope to look for the signs of infections, cancer, or any other disease which could be causing fluid collection in the pleural space. 
• ECG: During an electrocardiogram (ECG) electrical impulses are given to the heart to observe the heart rate, rhythm and the areas of diminished blood flow in the heart. This helps in diagnosing cardiogenic reasons for pulmonary edema.
• Echocardiogram: An echocardiogram helps in diagnosing various heart issues like a heart valve defect, abnormal working of the ventricles of the heart, fluid around the heart and congenital heart disease. This helps in diagnosing the cardiogenic reason for pulmonary edema.

The treatment of pulmonary edema depends on the cause, but the first line of treatment is to maintain the level of oxygen in the body.

Big hospitals have hyperbaric chambers to elevate the level of oxygen in the body. These chambers comprise an enclosed space or glass capsule where doctors can pump oxygen. This may help to improve some of the symptoms like difficulty in breathing and wheezing.

The other measures of treatment are:

• Cardiac defects are treated according to the diagnosis, in order to increase the heart function and reduce the pressure on the lungs. 
• The doctors may prescribe diuretics like furosemide (Lasix) to decrease the pressure due to the accumulation of fluid in the lungs. Diuretics help in decreasing the level of salt and water in the body, thus maintaining the blood pressure.
• Anti-hypertensive medications which are given to reduce high blood pressure can be given to reduce the pressure caused due to accumulation of fluid in the lungs.
• High dose pain killers like morphine are given to the patient to reduce the pain and anxiety.
• In case of complete respiratory failure, positive airway pressure breathing machines (CPAP, BiPAP) are used to insert air into the lungs. This is a short- term procedure which lasts for only a couple of hours.