List five substances that can fill the alveolar spaces in disease and give examples of situations in which this may occur.

1. Water: CHF, neurogenic edema, ARDS
2. Blood: contusion, vasculitis
3. Pus: bacterial pneumonia, tuberculosis
4. Proteinaceous fluid: alveolar proteinosis
5. Cells: bronchoalveolar cell carcinoma, lymphoma, eosinophils