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Created page with '*Excessive fluid in the lung *Normally, mechanisms are in place to protect the lung from the entry of circulatory fluid into alveolar spaces (See [[Respiratory System General In…'
*Excessive fluid in the lung
*Normally, mechanisms are in place to protect the lung from the entry of circulatory fluid into alveolar spaces (See [[Respiratory System General Introduction - Pathology#Lungs|functional anatomy]])
*Occurs when exudation of fluid from vessels into interstitium or alveoli exceeds the rate of alveolar or lymph removal
*Generally a sequel to or part of congestion or inflammatory process
*Generally begins as '''interstitial oedema''' characterised by expansion of perivascular and peribronchial and peribronchiolar fascia and distension of interstitial lymphatics
*Only when this interstitial compartment is overwhelmed does fluid flood the airspaces causing '''alveolar oedema'''
*Gross pathology:
**Heavy wet lungs which do not properly collapse
**Subpleural and interstitial tissue distended with fluid
**Foamy fluid oozing from the cut surface and airways
*Micro pathology:
**Pinkish fluid in alveoli and airways in association with air bubbles, and also in dilated lymphatics of the interstitium
**Colour of the fluid enhanced in cases where the endothelium is damaged - more protein present
**In slowly developing cases, macrophages contain haemosiderin
*The major causes of pulmonary oedema are:
**Increased capillary or type I epithelial permeability caused by
***Systemic toxins
***Shock
***Inhaled caustic gases
**Increased capillary hydrostatic pressure ('''cardiogenic oedema''' - left-sided or biventricular heart failure, sympathetic stimulation in acute brain damage)
**Decreased plasma oncotic pressure (hypoalbuminaemia)
**Overloading in excessive fluid therapy
**As part of inflammatory process
[[Category:To Do - Respiratory]]
*Normally, mechanisms are in place to protect the lung from the entry of circulatory fluid into alveolar spaces (See [[Respiratory System General Introduction - Pathology#Lungs|functional anatomy]])
*Occurs when exudation of fluid from vessels into interstitium or alveoli exceeds the rate of alveolar or lymph removal
*Generally a sequel to or part of congestion or inflammatory process
*Generally begins as '''interstitial oedema''' characterised by expansion of perivascular and peribronchial and peribronchiolar fascia and distension of interstitial lymphatics
*Only when this interstitial compartment is overwhelmed does fluid flood the airspaces causing '''alveolar oedema'''
*Gross pathology:
**Heavy wet lungs which do not properly collapse
**Subpleural and interstitial tissue distended with fluid
**Foamy fluid oozing from the cut surface and airways
*Micro pathology:
**Pinkish fluid in alveoli and airways in association with air bubbles, and also in dilated lymphatics of the interstitium
**Colour of the fluid enhanced in cases where the endothelium is damaged - more protein present
**In slowly developing cases, macrophages contain haemosiderin
*The major causes of pulmonary oedema are:
**Increased capillary or type I epithelial permeability caused by
***Systemic toxins
***Shock
***Inhaled caustic gases
**Increased capillary hydrostatic pressure ('''cardiogenic oedema''' - left-sided or biventricular heart failure, sympathetic stimulation in acute brain damage)
**Decreased plasma oncotic pressure (hypoalbuminaemia)
**Overloading in excessive fluid therapy
**As part of inflammatory process
[[Category:To Do - Respiratory]]