Table 2

Histological and biochemical alterations in pulmonary and extrapulmonary acute respiratory distress syndrome

	ARDSp	ARDSexp
Alveoli
Alveolar epithelium	↑↑Damage	Damage
Alterated type I and II cell	↑↑Damage	Normal
Alveolar neutrophils	Prevalent	Rare
Apoptotic neutrophils	Prevalent	Rare
Fibrinous exudates	Present	Rare
Alveolar collapse	↑↑Increased	Increased
Local interleukin	Prevalent	Rare
Interstitial space
Interstitial oedema	Absent	High
Collagen fibres	↑↑Increased	Increased
Elastic fibres	Normal	Normal
Capillary endothelium	Normal	↑↑Damage
Blood
Interleukin	Increased	↑↑Increased
TNF-α	Increased	↑↑Increased

ARDSp: pulmonary acute respiratory distress syndrome
ARDSexp: extrapulmonary acute respiratory distress syndrome