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Pulmonary edema: Fluid in the lungs due to left heart failure

In pulmonary edema, the alveoli are filled with fluid because the left side of the heart no longer works properly. This accumulation of fluid leads to shortness of breath. Heart problems are usually the cause of pulmonary edema. But fluid retention also has other causes. Shortness of breath, blue or pale skin color and excessive sweating are some symptoms of pulmonary edema. The condition develops suddenly or slowly. Acute pulmonary edema is a medical emergency in which the patient urgently needs oxygen and medication. The outlook is variable and depends on the cause, the severity and extent of the symptoms and the speed and effectiveness of treatment.

  • Synonyms pulmonary edema
  • Causes: Fluid in the lungs due to left heart failure
  • Symptoms
  • Diagnosis and examinations
  • Treatment via oxygen and medication
  • Complications
  • Prognosis


Synonyms pulmonary edema

Pulmonary edema is also known under these synonyms:

  • heart failure – pulmonary edema
  • pulmonary congestion
  • pulmonary congestion
  • water lung


Causes: Fluid in the lungs due to left heart failure

Heart disease

When the function of the left side of the heart is impaired and therefore no longer pumps properly, fluid accumulates in the pulmonary veins. This occurs after heart disease, high blood pressure (hypertension) and heart valve disorders. The accumulated fluid then leaks into the alveoli, disrupting oxygen absorption. This leads to a drop in blood pressure in the rest of the body. The body responds to this by narrowing the blood vessels (vasoconstriction), causing the kidneys to retain more fluid, worsening the situation in the lungs. Congestive heart failure (poor pumping of blood by the heart) leading to pulmonary edema is the result of:

  • a heart attack, or a condition of the heart that weakens or stiffens the heart muscle (cardiomyopathy: heart muscle disease)
  • sudden, severe high blood pressure (hypertension)
  • leaky or narrowed heart valves (mitral valve or aortic valve)


Other causes

Other causes of pulmonary edema include:

  • near-drowning
  • an exposure to high altitude
  • a serious injury such as a head injury
  • an intracranial hemorrhage (bleeding in the cerebral skull)
  • a pulmonary embolism (blockage of an artery in the lungs)
  • an overdose of aspirin, methadone or heroin
  • a subarachnoid hemorrhage (bleeding between meninges with headache, stiff neck and eye problems)
  • epileptic attacks
  • the use of certain medications
  • inhaling smoke
  • lung damage caused by inhaling toxic gas or a serious infection
  • renal failure (decreased or absent kidney function)
  • narrowed arteries that supply blood to the kidneys



The symptoms depend on acute or chronic pulmonary edema. The patient certainly does not have all the symptoms and the severity and extent also varies greatly.

  • acute respiratory distress
  • breathing problems while lying down (orthopnea)
  • anxiety or restlessness
  • cyanosis (blueness of the skin and mucous membranes)
  • decrease in the level of alertness
  • dizziness
  • a pale skin color (pallor)
  • grunting, gurgling, or wheezing
  • rapid weight gain (in chronic pulmonary edema)
  • pass out
  • feeling of “air hunger” or “drowning” (= paroxysmal nocturnal dyspnea): the patient wakes up and then tries to catch his breath
  • palpitations (palpitations)
  • headache
  • fever
  • shortness of breath (dyspnoea) which worsens when lying down
  • coughing up blood or bloody sputum (mucus)
  • excessive sweating (hyperhidrosis)
  • speech problems due to shortness of breath
  • fatigue
  • little urination (oliguria) due to the drop in blood pressure
  • weakness
  • swelling of the legs or abdomen


Diagnosis and examinations

Physical examination

The doctor performs a thorough physical examination. He listens to the breathing sounds of the lungs and the sounds of the heart with a stethoscope (auscultation). He identifies the following symptoms: abnormal heart sounds, rapid breathing (tachypnea), accelerated heart rate (tachycardia) and crackles and rattling sounds (rattles) in the lungs (ronchi).He also notices abnormal swelling of the legs. Fluid accumulation (ascites) also occurs in the abdomen, leading to swelling of the abdomen. The doctor also examines the neck veins that are abnormal, which may indicate high fluid levels in the body. The patient also has pale or blue skin. Other tests are needed to confirm the diagnosis.Electrocardiography (ECG) / Source: CardioNetworks, Wikimedia Commons (CC BY-SA-3.0)Diagnostic examination The doctor carries out the following examinations:

  • an echocardiography (ultrasound of the heart) to detect heart muscle problems
  • an electrocardiography (ECG: measurement of the electrical activity of the heart) to detect signs of a heart attack or problems with the heart rhythm
  • pulse oximetry (measuring the oxygen level in the blood)
  • a chest x-ray (x-ray of the chest)
  • a complete blood count


Treatment via oxygen and medication

In acute pulmonary edema, the doctor must often first resuscitate the patient. The patient is administered oxygen through a face mask or a plastic tube placed in the nose. Sometimes the doctor places a tube in the trachea, which the doctor then connects to the breathing machine. The patient is given morphine intravenously (through a vein) to dilate the arteries. This causes less pressure on the heart. The doctor also gives the patient intravenous diuretics (water pills). This causes the body to excrete excess fluid through urine. The patient also receives close monitoring in the coronary care unit or in the intensive care unit. ACE inhibitors (blood pressure lowering medications) and oral diuretics (water tablets that the patient takes by mouth) are necessary for the treatment of chronic heart failure. Other medicines that strengthen the heart muscle, control the heart rate and relieve pressure on the heart are also needed.


Pulmonary edema increases pressure in the pulmonary artery (pulmonary hypertension), and also causes right-sided heart failure. The right ventricle has a much thinner muscular wall than the left side of the heart because it is under less pressure to pump blood into the lungs. The increased pressure in the right atrium leads to:

  • A buildup of fluid in the tissues surrounding the lungs (pleural effusion)
  • Swelling of the abdomen and lower limbs
  • Swelling of the liver (hepatomegaly)



The outlook depends on the cause. The prospects for untreated patients are often very poor, resulting in a high mortality rate. Patients also sometimes die after treatment.

read more

  • Edema (fluid retention): Body parts affected and causes
  • Pulmonary embolism: Blockage of an artery in the lungs
  • Lung Cysts: Causes of cysts in the lungs
  • Lung abscess: Bacterial infection with abscess in lungs
  • Lung health: Tips for healthy lungs & good lung function

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