PATH 3610 Lecture Notes - Lecture 10: Acute Respiratory Distress Syndrome, Infant Respiratory Distress Syndrome, Restrictive Lung Disease
14 May 2018
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Alveolar injury: interstitial pneumonia and the acute respiratory distress syndrome
- alveolar injury: interstitial lung disease
o interstitial pneumonia
o diffuse alveolar damage
- cellular targets in interstitial lung injury
o type I pneumocytes: gas exchange, susceptible to injury, very little cytoplasm to afford gas
exchange
o type II pneumocytes: stem cell (regeneration), production of surfactant that lower surface
tension and prevent collapse of alveolar spaces, metabolism/detoxification, if damage to type I
then type II go under meiosis
- endothelial cells – very thin, lines capillary
- alveolar macrophages
- blood-air interface:
o type I pneumocyte
o basement membrane
o endothelium lining capillary
o thin barrier critical for efficient gas exchange
o effects on compliance
Evolution of alveolar injury
- acute: hyaline membranes and alveolar edema
- subacute: proliferation of type II pneumocytes
- chronic: interstitial fibrosis
Alveolar injury and restrictive lung disease
- obstruct oxygen exchange in alveoli
- reduce pulmonary compliance – stiff and inelastic
- reduce lung capacity – reduced tidal volume
- cat: idiopathic pulmonary fibrosis (IPF)
o interstitial lung disease
o alveolar structure replace by fibrous connective tissue
o progressive reduction in lung compliance and impaired gas exchange → dyspnea
Pneumoconiosis
- inhaling mineral dusts
o coal – carbon particle (anthracosis)
o silica sand (silicosis)
o asbestosis: disease caused by asbestos particles
Acute respiratory Distress Syndrome (ARDS)
- common cause of severe respiratory disease, patients hospitalized for other disease, rapid
progression and life threatening
- 36% mortality
- return to normal lung function in survivors
- interstitial lung disease
- symptoms
o sepsis or endotoxemia
o viral or myscoplasmal infection
o aspiration of vomitus
o trauma
o toxins
- pathogenesis: injury to type I pneumocystes or endothelium cells
- neonatal RDS: hyaline membrane disease
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Document Summary
Alveolar injury: interstitial pneumonia and the acute respiratory distress syndrome. Endothelial cells very thin, lines capillary. Blood-air interface: type i pneumocyte, basement membrane, endothelium lining capillary, thin barrier critical for efficient gas exchange, effects on compliance. Acute: hyaline membranes and alveolar edema subacute: proliferation of type ii pneumocytes chronic: interstitial fibrosis cat: idiopathic pulmonary fibrosis (ipf) Obstruct oxygen exchange in alveoli reduce pulmonary compliance stiff and inelastic reduce lung capacity reduced tidal volume: coal carbon particle (anthracosis, silica sand (silicosis, asbestosis: disease caused by asbestos particles. Pneumoconiosis inhaling mineral dusts interstitial lung disease: alveolar structure replace by fibrous connective tissue, progressive reduction in lung compliance and impaired gas exchange dyspnea. Acute respiratory distress syndrome (ards) common cause of severe respiratory disease, patients hospitalized for other disease, rapid progression and life threatening. 36% mortality return to normal lung function in survivors interstitial lung disease symptoms: sepsis or endotoxemia, viral or myscoplasmal infection, aspiration of vomitus, trauma, toxins.
