Œdème pulmonaire

Pulmonary oedema is defined as an excessive accumulation of endogenous liquid in the interstitium, cells, and bronchioles. An increase of the lymphatic drainage is the best protection against the increase of extravascular pulmonary liquid which results from two principal mechanisms: the augmentation of the capillary hydrostatic pressure and the modification of the permeability of the alveolo-capillary barrier. These two mechanisms are often associated and supported by others, such as the fall of interstitial hydrostatic pressure, fall of capillary oncotic pressure, or insufficiency of lymphatic drainage. Left cardiopathies are responsible for most pulmonary oedemas “of high pressure” whereas the oedemas “with high permeability” have very different causes with complex pathophysiological mechanisms, sometimes incompletely known. The clinical presentation is dominated by cough (often absent in cats) and dyspnoea. Thoracic radiography is the best complementary examination to confirm the presence of oedema. The evolution can be very rapid (acute pulmonary oedema) and requires emergency treatment. In such situation, absolute rest, oxygen therapy, use of diuretics - especially furosemide, constitute the first measures to be taken to limit oedema whatever is its origin. This therapeutic will be supplemented by the treatment of the causal disease. The prognosis depends on the stage of the oedema, the consequences on the respiratory function and the pathology which is at the origin of the oedema. The prognosis of the oedema with “high permeability” is less favourable than that of cardiogenic oedemas.