Table 1 Scoring system used to define the pathological changes in the lungs.
Score | Area affected | Epithelial degeneration/necrosis | Inflammation |
|---|---|---|---|
0 | None | None | None |
1 | 5−10% | Minimal; scattered cell necrosis/vacuolation affecting 5 to 10% of tissue section | Minimal; scattered inflammatory cells affecting 5−10% of tissue section |
2 | 10−25% | Mild; scattered cell necrosis/vacuolation | Multifocal, few inflammatory cells |
3 | 25−50% | Moderate; multifocal vacuolation or sloughed/necrotic cells | Thin layer of cells (<5 cell layer thick) |
4 | 50−75% | Marked; multifocal/segmental necrosis, epithelial loss/effacement | Thick layer of cells (>5 cell layer thick) |
5 | >75% | Severe; coalescing areas of necrosis, parenchymal effacement | Confluent areas of inflammation |
