Pulmonary edema

Pulmonary Oedema (British English), or edema (American English; both words from the Greek οἴδημα), is fluid accumulation in the air spaces and parenchyma of the lungs. It leads to impaired gas exchange and may cause respiratory failure. It is due to either failure of the left ventricle of the heart to adequately remove blood from the pulmonary circulation ("cardiogenic pulmonary oedema"), or an injury to the lung parenchyma or vasculature of the lung ("noncardiogenic pulmonary oedema"). Treatment is focused on three aspects: firstly improving respiratory function, secondly, treating the underlying cause, and thirdly avoiding further damage to the lung. Pulmonary oedema, especially acute, can lead to fatal respiratory distress or cardiac arrest due to hypoxia. It is a cardinal feature of congestive heart failure.

Signs and symptoms

The overwhelming symptom of pulmonary oedema is difficulty breathing, but may also include coughing up blood (classically seen as pink, frothy sputum), excessive sweating, anxiety, and pale skin. Shortness of breath can manifest as orthopnea (inability to lie down flat due to breathlessness) and/or paroxysmal nocturnal dyspnea (episodes of severe sudden breathlessness at night). These are common presenting symptoms of chronic pulmonary edema due to left ventricular failure. The development of pulmonary oedema may be associated with symptoms and signs of "fluid overload"; this is a non specific term to describe the manifestations of left ventricular failure on the rest of the body and includes peripheral oedema (swelling of the legs, in general, of the "pitting" variety, wherein the skin is slow to return to normal when pressed upon), raised jugular venous pressure and hepatomegaly, where the liver is enlarged and may be tender or even pulsatile. Other signs include end-inspiratory crackles (sounds heard at the end of a deep breath) on auscultation and the presence of a third heart sound.