Changes

*Micro pathology:  

*Micro pathology:  

**Early cases centred upon the bronchiolar alveolar junction with exudation, which extends into neighbouring alveoli

**Early cases centred upon the bronchiolar alveolar junction with exudation, which extends into neighbouring alveoli

**Exudate contains many [[[[Neutrophils - WikiBlood|Neutrophils]] - WikiBlood|neutrophils]], macrophages and oedema

**Exudate contains many [[Neutrophils - WikiBlood|neutrophils]], macrophages and oedema

**Alveolar capillaries are hyperaemic

**Alveolar capillaries are hyperaemic

**Some haemorrhages in severe cases - later stages contain more cells than fluid

**Some haemorrhages in severe cases - later stages contain more cells than fluid