Bat wing pulmonary edema takes its name from its appearance on a chest X-ray.
On chest X-ray there is
(1) alveolar edema in a central (hilar), nongravitational distribution
(2) absence of alveolar edema and interstitial fluid in the lung cortex (cortical sparing)
This is seen in severe heart failure that develops rapidly. It is seen in
(1) acute mitral insufficiency due to papillary muscle rupture, papillary muscle dysfunction, or infectious endocarditis.
(2) renal failure with fluid overload
