38/41: Pathology of the Lung Part 3 and Pneumoconioses - Carnevale Flashcards
what is a restrictive disease briefly?
expansion of lung is hampered by either things external to lung (deformed chest wall, pleural space filled with fluid) or things in the lung (parenchymal = edema, acellular material, granulomas, etc)
heterogenous group of disorders characterized by inflammation and fibrosis of the pulmonary connective tissue, principally the most peripheral and delicate interstitium in the alveolar walls
chronic diffuse interstitial diseases
hallmark of chronic diffuse interstitial diseases
reduced compliance (stiff lungs) –> dyspnea –> hypoxia
how can you clinically distinguish obstructive from restrictive diseases?
FEV1/FVC ratio is not reduced in restrictive disease
decreased total lung capacity
FEV normal
FEV/FVC ratio not reduced
=
intersitial lung disease
Presentation:
dyspnea, hypoxia, end-inspiratory crackles and eventual cyanosis
X-rays: diffuse bilateral infiltrative lesion by nodules, irregular lines, or ground glass shadows (infiltrative)
interstitial lung disease
interstitial lung disease can lead to …
pulmonary HTN or cor pulmonale
end stage = “ honeycomb lung”
non-cardiogenic pulmonary edema aka
acute lung injury ALI
abrupt onset of significant hypoxemia and pulmonary infiltrates in absence of cardiac failure; spectrum
severe ALI with greater hypoxemia
ARDS
what is the histological manifestation in both ARDS and ALI?
diffuse alveolar damage DAD
both are also associated with acute interstitial pneumonia
rapid onset of life-threatening respiratory insufficieny refractory to oxygen therapy caused by DAD
ARDS
most common cause of non-cardiogenic pulmonary edema
damage to capillary and alveolar membranes leads to…
ALI and ARDS
either direct or indirect injuries
bilateral pulmonary infiltrates on chest x-ray and pulmonary capillary wedge pressure less than 18mmHg
ALI/ARDS characteristic
PaOz/FiO2 less than 300 =
PaO2/FiO2 less than 200 =
300 ALI
200 ARDS
ie on 60% O2 the patients Pa)2 is less than 120 mmHg
explain the basic pathogenesis of ARDS
uncontrolled activation of acute inflammatory system; imbalance between proinflammatory and anti-inflammatory mediators. Sequestration and activation of PMN; diffuse damage to alveolar capillary walls
leads to increased vascular permeability and alveolar thickening
loss of diffusion capacity
widespread surfactant abnormalities
two key things seen in early phase of ALi and ARDS in the alveolus
hyaline membrane formation
PMN sequestration and migration into alveolus
adult v. neonate ARDS
adults: diffuse damage to alveolar capillary walls (inflammation gone out of control)
neonates: surfactant issues
what helps ARDS?
NO inhalation
- decreases PA pressure and arterial resistance
three phases of ARDS
acute exudative 0-7 d
proliferative phase 1-3 wk
fibrotic/healing phase 3-4 wk —> possible honeycomb lung
TRALI =
transfusion related ALI
no pre-existing acute lung injury before transfusion - occurs during or within 6 hours of transfusion due to anti-HLA or HNA antibodies
final stage of DID diffuse interstitial disease
end stage fibrotic lung aka honeycomb lung
what cell plays a central role in fibrosis with DID?
macrophage
pulmonary disorder of unknown etiology characterized by diffuse interstitial fibrosis aka cryptogenic fibrosing alveolitis
idiopathic pulmonary fibrosis
lung transplant is the only definitive therapy - diagnosis of exclusion
pathogenesis stages of IPF
early- fibroblastic foci
temporal heterogenity
late - dense fibrosis and honeycomb lung
