Pulmonary Edema: Causes, Symptoms and Treatment
Pulmonary edema (UK/Ireland: oedema) is fluid accumulation in the lungs, which collects in air sacs. This fluid collects in air sacs in the lungs, making it difficult to breathe. It leads to impaired gas exchange and may cause respiratory failure.
Pulmonary edema is mainly due to the heart not removing fluid from lung circulation properly (cardiogenic pulmonary edema). A direct injury to the lung parenchyma can also lead to pulmonary edema.
Treatment usually focuses on improving respiratory function and dealing with the source of the problem. It generally includes supplemental oxygen and medications. Acute pulmonary edema – the type that occurs suddenly – if a medical emergency. If treatment is prompt and adequate, pulmonary edema is rarely fatal.
Symptoms of pulmonary edema
A symptom is something the patient feels or reports, while a sign is something other people, including a doctor, may detect. For example, a headache may be a symptom, while a rash may be a sign.
Signs and symptoms that come on all of a sudden may include:
- Difficulty breathing
- Coughing up blood
- Excessive sweating
- Pale skin
- Pink frothy sputum (which may be coughed up)
- If left untreated can lead to coma and then death – usually due to hypoxia (oxygen deprivation)
If symptoms have been developing gradually, fluid overload symptoms may be present, including:
- Nocturia (getting up at night frequently to urinate)
- Swollen ankles (ankle edema), there may also be general swelling in the legs
- Orthopnea – the patient becomes breathless when lying down flat
- Paroxysmal nocturnal dyspnea – episodes of severe sudden breathlessness at night.
High altitude pulmonary edema symptoms – headache, sleeplessness, general edema and fluid retention, cough, and panting.
Causes of pulmonary edema
In normal breathing, small air sacs in our lungs (alveoli) fill up with each during each breath, taking in essential O2 (oxygen) and getting rid of C02 (carbon dioxide). If the alveoli are flooded two problems occur, the bloodstream cannot get its proper supply of O2, and the body is unable to get rid of C02 properly.
Pulmonary edema may be caused either by direct damage to tissue, or a result of a heart or circulatory system malfunction. If pulmonary blood pressure is above 15 mmHg, pulmonary edema may occur.
Cardiogenic (originating in the heart) causes of pulmonary edema:
- Congestive heart failure
- Fluid overload, such as from kidney failure or intravenous therapy
- Hypertensive crisis
- Pericardial effusion with tamponade
- Severe arrhythmias (tachycardia/fast heartbeat or bradycardia/slow heartbeat)
- Severe heart attack with left ventricular failure
Non-cardiogenic (not originating in the heart) causes of pulmonary edema:
- Acute respiratory distress syndrome
- Aspirin overdose
- High altitude
- Intracranial hemorrhage
- Kidney failure
- Methadone/heroin overdose
- Pleural effusion – too much liquid around the lung is removed, causing it to expand too quickly
- Pulmonary embolism
- Severe seizures
Diagnosis of pulmonary edema
The patient will undergo a physical exam first. The doctor will use a stethoscope and listen to the lungs for crackles and rapid breathing, and the heart for abnormal rhythms.
The doctor may also order the following diagnostic tests:
- Blood test – to determine blood oxygen levels.
- Chest x-ray – to see whether there is any fluid in or around the lungs. This imaging test may also be used to check the size of the heart.
- ECG (electrocardiogram) – to check heart rhythm and any evidence of a heart attack.
- Echocardiogram – this is an ultrasound scan of the heart.
Treatments for pulmonary edema
In order to get the patient’s blood oxygen levels back up, oxygen is given either through prongs (tiny plastic tubes) in the nose or a face mask. Sometimes a breathing tube may be placed into the trachea, or even a ventilator (breathing machine) may be required.
If the medical staff have determined that the pulmonary edema has a circulatory cause, the patient will be treated with intravenous nitrates, such as glycerol trinitrate, and loop diuretics, such as furosemide or bumetanide.
Altitude-induced pulmonary edema – sildenafil (Viagra) may be used as a preventative treatment.
Prevention of pulmonary edema
Treatment compliance (adherence) – patients who have a disease/condition that increases the risk of developing pulmonary edema should make sure they follow of the doctor’s instructions and recommendations, so that their condition is under control.
Diet and body weight– if you follow a healthy, well balanced diet and maintain an ideal bodyweight for your age and height, your risk of developing pulmonary edema will be much lower.