Table 1.

Scoring grid for histopathologic examination of lung tissue

ParameterScoreInterpretation
Inflammatory cells0No neutrophils, lymphocytes, or eosinophils in alveoli and lung tissue; normal amount of alveolar macrophages
1Slight increase in the number of any inflammatory cell population
2Recruitment of a large number of inflammatory cells
Hemorrhage0No erythrocytes in alveoli
1Few erythrocytes in alveoli
2Numerous erythrocytes
Edema0Absent
1Minimal swelling of alveolar walls
2Widespread swelling of tissue interstitium
Tissue injury0Absent
1Minimal modification in alveolar architecture
2Widespread disorganization of lung tissue, including injuries to organelles
Regeneration0Normal amount of type II pneumocytes and surfactant
1Slight increase in the number of type II pneumocytes and surfactant secretion
2Marked increase in type II pneumocytes and surfactant