Pulmonary Edema - Alveolar

Pathophysiology:  Airspace disease: any process which replaces air in alveoli.  The abnormal material may be: water, blood, tumor, pus, aspirant, or surfactant.  In cardiogenic and non-cardiogenic edema, water, electrolytes, and proteinaceous material fill the alveoli.

Clues:  One airspace disease looks like any another and differentiating them generally needs clinical correlation. Some radiologic hints indicating edema are:

1.      perihilar or batwing symmetry of edema

2.      typical pericardiac and peridiaphragmatic lucent margins (cardiac/renal edema)

3.      enlarged heart and valvular calcifications

4.      chronology: airspace disease which appears rapidly (minutes) and clears rapidly (hours to days)

“Aunt Sophies”:  Any airspace disease

1.      Infections: all the CAP

2.      Tumor: bronchoalveolar cell cancer, lymphoma, metastases

3.      Bleeding: vasculitis  (eg. Goodpasture’s syndrome), coagulopathies, trauma, anticogulants

4.      Aspiration pneumonia and chronic lipid pneumonia

5.      Acute silico-proteinosis, alveolar proteinosis